December 2014

Kilauea Volcano Lava Inches Closer to Pahoa Marketplace

Kilauea Volcano Lava Inches Closer to Pahoa Marketplace

Lava from Kilauea Volcano stopped short of hitting Pahoa Marketplace on Christmas day but it has resumed its movement and has moved 15 y...

Cappadocia Fairy Chimneys - Turkey

tourism 8:47 PM

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<a href="http://4.bp.blogspot.com/-VrQpysUcUtM/VKPW00o4f8I/AAAAAAAADas/ZNPZyp7sfYk/s1600/flat%2C550x550%2C075%2Cf.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><span style="font-family: inherit;"><img alt="Cappadocia Fairy Chimneys- Turkey" border="0" height="425" src="https://4.bp.blogspot.com/-VrQpysUcUtM/VKPW00o4f8I/AAAAAAAADas/ZNPZyp7sfYk/s640/flat%2C550x550%2C075%2Cf.jpg" title="" width="640" /></span></a></div>
<span style="font-family: inherit;"><br />
</span> <span style="color: #252525; font-family: inherit;"><span style="background-color: white; line-height: 22.3999996185303px;">Is a historical region in Central Anatolia, largely in the Nevşehir, Kayseri,Aksaray, and Niğde Provinces in Turkey.</span></span><br />
<span style="color: #252525; font-family: inherit;"><span style="background-color: white; line-height: 22.3999996185303px;"></span></span><br />
<span style="color: #252525; font-family: inherit;"><span style="line-height: 22.3999996185303px;">The name “Cappadocia” dates back to Persian times, when the region was called as “katpatukya” meaning “Land of Beautiful Horses”. Since that time Cappadocia has seen the rise and fall of many different civilizations. It is a land of vast plains, rolling hills, rugged mountains and extinct volcanoes. It is a veritable treasure of historical relics from the Chalcolithic era to the Seljuk Turks period. The visitor may seldom travel more then a few miles without encountering some wonderful reminders of Cappadocia's colorful past.</span></span><br />
<span style="color: #252525; font-family: inherit;"><span style="line-height: 22.3999996185303px;"><br />
</span></span> <span style="color: #252525; font-family: inherit;"><span style="line-height: 22.3999996185303px;">In recent times, Cappadocia became famous for its unique landscape of valleys and unusual rock formations, known as "fairy chimneys". The formation of this strange landscape started during the third geological period, when three volcanoes located on the edges of this region began erupting frequently. </span></span><br />
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<span style="color: #252525; font-family: inherit;"><span style="line-height: 22.3999996185303px;">The deposits of volcanoes ash, lava and basalt laid the foundations for today's landscape. Earthquakes and ongoing effects of erosion have contributed to form the valleys and the "fairy chimneys" that can be seen today.</span></span><br />
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="http://2.bp.blogspot.com/-Rdnr5v2SiKY/VKQ2hrbbl_I/AAAAAAAADbQ/E-ssvX4ssOs/s1600/Turkey_Goreme_phallic_fairy_chimneys_4b2de55f788f4f37bb050ba9535fab5f.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img alt="Cappadocia Fairy Chimneys- Turkey" border="0" height="425" src="https://2.bp.blogspot.com/-Rdnr5v2SiKY/VKQ2hrbbl_I/AAAAAAAADbQ/E-ssvX4ssOs/s640/Turkey_Goreme_phallic_fairy_chimneys_4b2de55f788f4f37bb050ba9535fab5f.jpg" title="" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">fairy chimneys</td></tr>
</tbody></table>
<span style="color: #252525; font-family: inherit;"><span style="line-height: 22.3999996185303px;"><br />
</span></span> <span style="color: #252525; font-family: inherit;"><span style="line-height: 22.3999996185303px;">As the rock below the top layer of basalt is extremely soft, it can be easily carved. Communities took advantage of this to make their home in the rock pillars and under the ground. Today, these examples of homes, churches and whole cities abound in Cappadocia.</span></span><br />
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<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="http://2.bp.blogspot.com/-CZWJ_g5J0TI/VKPZ35ZEHoI/AAAAAAAADa4/TK9fcpCZrkU/s1600/Cappadocia_Aktepe_Panorama.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><span style="font-family: inherit;"><img alt="Cappadocia Fairy Chimneys- Turkey" border="0" height="240" src="https://2.bp.blogspot.com/-CZWJ_g5J0TI/VKPZ35ZEHoI/AAAAAAAADa4/TK9fcpCZrkU/s640/Cappadocia_Aktepe_Panorama.JPG" title="" width="640" /></span></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><i><span style="font-family: inherit; font-size: x-small;">A panorama view of Aktepe Hill, a mountain north-east of Göreme in Cappadocia in Central Turkey. </span></i></td></tr>
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<h4>
<span style="font-family: "georgia" , "times new roman" , serif;">GEOLOGICAL FORMATION</span></h4>
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<span style="font-family: inherit;">The surrealistic geological formation of Cappadocia is one of the wonders of the world. It is the result of the natural forces during the intense volcanic activity.</span></div>
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<span style="font-family: inherit;">In addition to the European Alps, the Taurus Mountains of southern Anatolia were formed during the Tertiary period of geological development (65 million to 2 million years ago). During the "Alpine period" of mountain-building, deep fissures and large depressed areas were created. The fracturing process allowed the subsurface magma (rocks in their molten state) to find its way to the surface where it formed the Erciyes, Develi, Melendiz, Kegiboydoran, and Hasan Dag cones.</span></div>
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<span style="font-family: inherit;"><br />
</span></div>
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<span style="font-family: inherit;">After numerous eruptions these cones increased in size and formed a chain of volcanoes running parallel to the Taurus Mountains. Also the volcanic material slowly ran towards the depressed areas and covered the previously formed hills and valleys. This geological activity changed the general landscape of the region, giving it the appearance of a plateau.</span></div>
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<span style="font-family: inherit;"><br />
</span></div>
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</span></div>
<div>
<span style="font-family: inherit;">Wind, climate, mechanical weathering, rain, snow, and rivers caused the erosion giving to Cappadocia its unusual and characteristic rock formations. The Cappadocian climate, with sharp changes of temperature, heavy rains, and melting snow in the spring, plays an important role in the formation of the Cappadocian landscape.</span><br />
<br />
<span style="font-family: inherit;">In addition, mechanical weathering is responsible for fragmentation because rocks expand when heated and break up as they cool. Frozen water in the cracks can also cause fragmentation. However, the most important sources of erosion are rain and rivers. </span><br />
<br />
<span style="font-family: inherit;">Heavy rainfall transformed the smooth surface of the plateau into a complex pattern of gullies that followed preexisting fissures in the rocks. Eroded materials were then removed by the rivers. Sometime streams and rivers made very sharp vertical cuts into the volcanic soil and created isolated pinnacles at the intersection of two or more gullies. Rain and rivers also formed valleys such as Zelve and Goreme.</span></div>
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<a href="http://4.bp.blogspot.com/-MbUvWJBYcpQ/VKPazaa-iII/AAAAAAAADbA/i35_eePtwM8/s1600/1330604013_Cappadocia-Turkey.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><span style="font-family: inherit;"><img alt="Cappadocia Fairy Chimneys- Turkey" border="0" height="459" src="https://4.bp.blogspot.com/-MbUvWJBYcpQ/VKPazaa-iII/AAAAAAAADbA/i35_eePtwM8/s640/1330604013_Cappadocia-Turkey.jpg" title="" width="640" /></span></a></div>
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<span style="font-family: "georgia" , "times new roman" , serif;">see also:</span><br />
<span style="font-family: "georgia" , "times new roman" , serif;"><a href="http://www.geologyin.com/2014/11/the-green-sand-beach-mahana-beach.html">The Green Sand Beach ( Mahana Beach )</a><br />
<a href="http://www.geologyin.com/2014/10/monte-roraima-real-lost-world.html">Monte Roraima "The Real Lost World"</a><br />
<a href="http://www.geologyin.com/2014/06/spectacular-neon-blue-lava-pours-from.html">Spectacular Neon Blue Lava Pours From Indonesia's Kawah Ijen Volcano At Night (PHOTOS)</a></span></div>

Cappadocia Fairy Chimneys - Turkey

Is a historical region in Central Anatolia, largely in the Nevşehir, Kayseri,Aksaray, and Niğde Provinces in Turkey. The name “Capp...

Seismic Facies Analysis

Oil, Seismic 8:30 PM

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<b>Seismic facies </b>are "mappable, three dimensional seismic units composed of groups of reflections whose parameters differ from those of adjacent facies units”.</div>
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Seismic facies analysis is the description and interpretation of seismic reflection parameters, such as configuration, continuity, amplitude, and frequency, within the stratigraphic framework of a depositional sequence.<br />
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Its purpose is to determine all variations of seismic parameters within third-order sequences and their systems tracts in order to determine lateral lithofacies and fluid type changes. Of these parameters, reflection pattern geometries are perhaps the most useful for calibration with lithofacies interpreted from <b>well logs</b>, <b>cores</b>, and <b>cuttings</b>.</div>
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<span style="font-size: small;"><span style="font-family: "georgia" , "times new roman" , serif;"><span style="font-family: inherit; font-size: medium;"><b>Reflection parameters</b></span></span></span></h3>
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<b>Depositional environment,</b> sediment source, and lithofacies can be interpreted by grouping these parameters into mappable, three-dimensional seismic facies.The table below summarizes the information obtained from each parameter.<br />
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<b>Additional </b>techniques for improving resolution and enhancing interpretations of seismic facies include the following:</div>
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<div>
<ul style="text-align: left;">
<li>Seismic forward modeling</li>
<li>Changing display scale for seismic data</li>
<li>Changing display type for seismic data</li>
<li>Using 3-D seismic displays</li>
</ul>
</div>
</div>
<h3 style="text-align: left;">
<span style="font-family: "georgia" , "times new roman" , serif;"><span style="font-size: small;"><b>Seismic facies mapping</b></span></span></h3>
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<div>
Seismic facies <b>maps </b>show the areal distribution of seismic facies and are useful when making lithofacies interpretations. The most common and useful parameters to be mapped are seismic reflection patterns and isochrons (thickness measured in seconds of two-way time).</div>
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<br /></div>
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<b>The steps below outlines a suggested procedure for mapping seismic facies.</b></div>
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<div>
<ol style="text-align: left;">
<li>Identify sequences that contain potential traps, seal rocks, reservoir rocks, or source rocks.</li>
<li>Make regional seismic reflection pattern maps and isochron maps of those sequences. If possible, make maps of lowstand, transgressive, and highstand systems tracts.</li>
</ol>
<div>
<div>
<span style="font-family: "georgia" , "times new roman" , serif;"><b><span style="color: blue;">Read also:</span></b></span><br />
<a href="http://www.geologyin.com/2014/12/hydrocarbon-traps.html" target="_blank">Hydrocarbon traps</a><br />
<a href="http://www.geologyin.com/2014/08/petroleum-system.html" target="_blank">The Petroleum System</a></div>
</div>
</div>
</div>
</div>
</div>

Seismic Facies Analysis

Seismic facies are "mappable, three dimensional seismic units composed of groups of reflections whose parameters differ from thos...

Re-thinking Southern California earthquake scenarios in Coachella Valley, San Andreas Fault

11:24 PM

Re-thinking Southern California earthquake scenarios in Coachella Valley, San Andreas Fault

New 3D numerical modeling that captures more geometric complexity of an active fault segment in southern California than any other sugge...

Fossils and Their Environments

Fossils 10:01 PM

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<br />
Fossils are the remains or traces of once living organisms. Our introduction to paleontology (the study of fossils), will be limited to those forms that are commonly preserved and geologically useful. <br />
<h3 style="text-align: left;">
<span style="font-size: small;"><span style="font-family: Georgia, "Times New Roman", serif;">For Historical Geology purposes, we will be concerned with two aspects of paleontology: </span></span></h3>
(1) fossils as indicators of relative age (using the Principle of Floral and Faunal Succession. fossils as indicators of environment. All organisms are dependent on their environments for survival. Some organisms, however, can survive only in restricted environments.<br />
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Consequently, we can apply the principle of uniformitarianism to fossils to interpret the environment in which they lived. Modern fish, for example, tend to live in water. Ancient fish, then, probably lived in water as well. We will divide the environments into two basic categories-- the terrestrial (land-based) environment, and the marine (ocean) environment. Because marine fossils are most commonly preserved, the marine environments are shown in figure1.<br />
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Shallow marine bottom-dwelling organisms such as corals represent the benthic environment. Similarly, some species of fish indicate the neritic environment (the shallow seas covering the continental shelves). Other organisms such as radiolarians and some diatoms are characteristic of the oceanic or deep ocean environment. Still other organisms inhabit the ocean in both the neritic and oceanic areas and simply suggest a pelagic environment.<br />
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Marine fossils can be further described in terms of their life habits. These habits are shown in Figure A2.  Corals, for example tend to be attached to the bottom and are thus referred to as benthic (bottom dwelling) sessile (fixed). Lobsters, however, move along the ocean bottom and although still benthic, are also considered vagrant. Swimming and floating organisms are referred to as nektonic and planktonic, respectively. In our example above, some fish might represent the nektonic pelagic environment.<br />
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Fossils and Their Environments

Fossils are the remains or traces of once living organisms. Our introduction to paleontology (the study of fossils), will be limited to ...

Photographs in the Geological works

Fieldwork, Geologist 9:36 PM

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<a href="http://1.bp.blogspot.com/-VX30N7tvbiU/VKGell4d6aI/AAAAAAAADV0/egBEygDUnhc/s1600/Berthoud-6121.jpg" imageanchor="1"><img alt="Photographs in the Geological works" border="0" height="266" src="https://1.bp.blogspot.com/-VX30N7tvbiU/VKGell4d6aI/AAAAAAAADV0/egBEygDUnhc/s1600/Berthoud-6121.jpg" title="Photographs in the Geological works" width="400" /></a></div>
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<span style="font-family: inherit;">Photographs are a key
part of most geological fieldwork. They can serve as an aide memoire , be used
for image analysis to document changes in an exposure over time and are also
essential to illustrate key geological features in a report, talk or publication. </span><br />
<br />
<span style="font-family: inherit;">As <a href="http://www.geologyin.com/2014/11/the-field-notebook.html" target="_blank"><span style="color: black;">outlined</span><b><span style="color: red;"> </span>in this Section</b></a>. it is very important in the field not only to
take a photograph but also to make field notes and sketches, because a
photograph is not a replacement for a field sketch. A field sketch records how
you have divided up the succession, provides a key to further notes and shows
some geological interpretation. The photographs taken should be recorded in
your field notebook and electronic information on the geological features and
location added either through the camera or image processing software.</span></div>
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<span style="font-family: inherit;"><br /></span></div>
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<span style="font-family: inherit;"><br /></span></div>
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<span style="font-family: inherit;">The
detailed advantages and disadvantages of the wide range of cameras available on
the market are outside of the scope of this book, so here we provide some
general comments. Digital single - lens reflex (SLR) cameras provide the most
amount of flexibility for a range of lighting conditions and types of photograph;
they also generally have better lenses. However, many compact cameras give
excellent results and have the added advantage that they are small and light.
As with Personal Digital Assistants (PDAs), etc. check if the screen is visible
under strong lighting conditions. This is essential when the camera does not
have a view finder. </span><br />
<br />
<div class="separator" style="clear: both; text-align: center;">
<a href="http://2.bp.blogspot.com/-83rPRyUnAR4/VKGbkSKL2RI/AAAAAAAADVg/UEhAdUsXyGw/s1600/Untitledxx.jpg" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" height="160" src="https://2.bp.blogspot.com/-83rPRyUnAR4/VKGbkSKL2RI/AAAAAAAADVg/UEhAdUsXyGw/s1600/Untitledxx.jpg" width="200" /></a></div>
<span style="font-family: inherit;">If the camera does have a view finder but is not an SLR,
the view finder does not usually give an exact representation of the frame of
the photograph so you may need to work out exactly what that is if you wish to
frame your subject exactly. Even with digital SLRs the view is not exactly the
same. Cameras with good reviews for outdoor and scenic use will probably give
the best geological field photographs. A good macro lens setting is
advantageous if you are going to take a lot of close up photographs. In
addition cameras that are sensitive to a wide range of lighting conditions
allow maximum flexibility. There is almost no limit to the number of
photographs you can take with a digital camera, provided that is you have
enough memory and battery capacity for the camera. This means you can take
many more photographs than you will eventually use.<o:p></o:p></span></div>
<div class="MsoNormal" style="margin-bottom: 0.0001pt;">
<h4 style="text-align: left;">
<span style="font-family: Georgia, "Times New Roman", serif;"><span style="font-family: inherit;">The following
tips may help give you a set of photographs that cover all eventualities.<o:p></o:p></span></span></h4>
</div>
<div class="MsoNormal" style="margin-bottom: 0.0001pt;">
</div>
<ul style="text-align: left;">
<li><span style="font-family: inherit;">Make the first
photograph at a locality a general view; this will remind you of where the
photographs that follow on were taken.</span></li>
<li><span style="font-family: inherit;">Take both
general views and close - up views of different features.</span></li>
<li><span style="font-family: inherit;">Take note of
the lighting conditions. The best view under sunny conditions is often with the
sun behind you, so this may mean returning to a locality at a different time of
day to get the best lighting. Cloudy conditions provide a more even light, but
sunny conditions can show some geological features better.</span></li>
<li><span style="font-family: inherit;">If the
lighting conditions are poor or variable take several shots with different
settings. Note <div class="separator" style="clear: both; text-align: center;">
<a href="http://1.bp.blogspot.com/-Xu98EMmlWls/VKGcO-K2zOI/AAAAAAAADVo/6nmXupG3V5A/s1600/cccc.jpg" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" height="320" src="https://1.bp.blogspot.com/-Xu98EMmlWls/VKGcO-K2zOI/AAAAAAAADVo/6nmXupG3V5A/s1600/cccc.jpg" width="188" /></a></div>
that underexposed digital photographs can be processed later to
achieve a good image whereas overexposed photographs do not record all of the information.
In Figure  , (b) is better than (a).<br /><div class="MsoNormal" style="margin-bottom: 0.0001pt;">
<span style="font-family: inherit;"><span style="font-size: 9pt;">(a)
Auto setting. (b) After </span><span style="font-size: 9pt;">using
a white balance card to </span><span style="font-size: 9pt;">adjust
the balance for the lighting </span><span style="font-size: 9pt;">conditions
(seek advice from </span><span style="font-size: 9pt;">professional
photographer/ </span><span style="font-size: 9pt; line-height: 115%;">photographic shop).</span></span></div>
</span></li>
<li><span style="font-family: inherit;">If you are
using the photograph for image analysis ensure that it does not have any edge
distortion, for instance that produced by using a wide - angle setting, or
taking photos with the lens set to 50 mm or longer focal length. You will also
need to take account of white balance under different lighting conditions.</span></li>
<li><span style="font-family: inherit;">Under low
lighting conditions a tripod is useful; if you do not have a tripod with you try
setting the camera up on a rock and using the self-timer or a remote shutter
release.</span></li>
<li><span style="font-family: inherit;">If you are
working where weather conditions are bad consider purchasing a waterproof
camera case of the type used by divers for underwater photography.</span></li>
<li><span style="font-family: inherit;">If you are taking
a lot of photographs, for instance of shell beds or fi ne - scale detail, take
the photographs in stratigraphic order to avoid confusion and consider marking
the rocks in some manner, for instance with a marker pen, correction fluid or a
tile scribe, so you know how the different photographs relate to each other.</span></li>
<li><span style="font-family: inherit;">In most
instances it is best if you stand perpendicular to the object being
photographed.</span></li>
<li><span style="font-family: inherit;">You can use
the white pages of a notebook to reflect light into the shadowed portions of
exposures, especially under  overhangs.</span></li>
<li><span style="font-family: inherit;">Include a
scale or make a note of the size of the area being photographed. Depending on
the subject of the photograph this could be anything from another person to a
ruler, camera lens cap, coin or penknife. For small – scale photographs a finger
is also useful and one of the advantages of this is that you will not
inadvertently leave it behind! Ideally with medium and small objects use a
metric scale rather than an object such as a lens cap or coin because these
have variable dimensions. In addition the scale should preferably be of a
neutral colour (grey) so that it will not unduly affect photographic exposure. Alternatively
draw a scale on the cover of your notebook with a bold marker pen.</span></li>
<li><span style="font-family: inherit;">When taking a
photograph of an area you have sketched consider including the field notebook
page in one corner of one of the photographs as a means of cross referencing between
the photographs and your field notebook (assuming the field of view is
appropriate).</span></li>
<li><span style="font-family: inherit;">Assuming you
are using a digital camera check, using the camera display screen, the exposure
and as far as possible that the focus is OK before you leave the locality so
that you can take another photograph if necessary.</span></li>
</ul>
<div>
<a href="http://www.geologyin.com/search/label/Fieldwork" target="_blank"><b><span style="color: blue;">Read more about the geological fieldwork Here</span></b></a></div>
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Photographs in the Geological works

Photographs are a key part of most geological fieldwork. They can serve as an aide memoire , be used for image analysis to document c...

Facies And Facies Sequences

sedimentary, Stratigraphy 11:07 AM

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<h4 style="text-align: left;">
<span style="font-family: Georgia, "Times New Roman", serif;"> Facies</span></h4>
<div style="text-align: left;">
A facies is a body of rock with specific characteristics. It is properly defined on the basis of color, bedding, composition, texture, fossils, and sedimentary structures. However, the term “facies” is also used in many other senses. </div>
<div style="text-align: left;">
<br /></div>
<div style="text-align: left;">
It is used as a strict observational sense of a rock product (sandstone facies), in a genetic sense for the products of a process by which a rock is thought to have formed (turbidite facies), in an environmental sense for the environment in which a rock is thought to have formed (fluvial facies), and as a tecto-facies (post-orogenic facies). All these uses are acceptable, as long as you remember which concept is being used.</div>
<div style="text-align: left;">
<br /></div>
<div style="text-align: left;">
<span style="font-family: "georgia" , "times new roman" , serif;">Facies distributions and changes are dependant on a number of interrelated influences, which include:</span></div>
<ul style="text-align: left;">
<li>Sedimentary Processes</li>
<li>Sediment supply</li>
<li>Climate</li>
<li>Tectonics</li>
<li>Sea Level changes</li>
<li>Biological Activity</li>
<li>Water Chemistry</li>
<li>Volcanism</li>
</ul>
<div style="text-align: left;">
<br /></div>
<div style="text-align: left;">
<br /></div>
<div style="text-align: left;">
<br /></div>
<span style="font-family: Georgia, "Times New Roman", serif;"><br /></span><h4>
<span style="font-family: Georgia, "Times New Roman", serif;"> Facies Sequence</span></h4>
<div style="text-align: left;">
A facies sequence is a series of facies that pass gradually from one into another. A sequence can have an abrupt or erosive boundary, or be bounded by a hiatus, as indicated by a rootlet bed, reworking, or early diagenesis.</div>
<div style="text-align: left;">
<br /></div>
<div style="text-align: left;">
Clastic environments have two important types of sequences. In one, there is a coarsening upward sequence that develops above a sharp or erosional base; a second type is the fining upward sequence. This is important in interpretation of depositional environments, because grain size is normally a measure of the hydraulic power at the time of deposition and a coarsening upward sequence indicates an increase in flow power. </div>
<div style="text-align: left;">
<br /></div>
<div style="text-align: left;">
This may be due to shallowing as a delta, shoreline, or river crevasse builds out into deeper water, or to progradation of a submarine fan. Fining upward sequences can be formed by a migrating point bar in a river or by filling of an abandoned channel.</div>
<h4 style="text-align: left;">
<span style="font-family: Georgia, "Times New Roman", serif;"> Walther's Law</span></h4>
<div style="text-align: left;">
Walther's Law states that “the various deposits of the same facies area and, similarly, the sum of the rocks of different facies areas were formed beside each other in space, but in a crustal profile we see them lying on top of each other...it is a basic statement of far-reaching significance that only those facies and facies areas can be superimposed, without a break, that can be observed beside each other at the present time.”</div>
<div style="text-align: left;">
<br /></div>
<div style="text-align: left;">
This is interpreted to mean that facies occurring in a conformable vertical sequence were formed in aerially adjacent environments and the facies in vertical contact must be the product of neighboring environments.</div>
<h4 style="text-align: left;">
<span style="font-family: Georgia, "Times New Roman", serif;">See also:</span></h4>
<div style="text-align: left;">
<span style="font-family: Georgia, "Times New Roman", serif;"><a href="http://www.geologyin.com/2015/09/sequence-stratigraphy.html" target="_blank">Types of Unconformities </a></span></div>
<div style="text-align: left;">
<span style="font-family: Georgia, "Times New Roman", serif;"><a href="http://www.geologyin.com/2015/09/sequence-stratigraphy.html" target="_blank">Sequence Stratigraphy</a></span></div>
</div>

Facies And Facies Sequences

Facies And Facies Sequences Facies A facies is a body of rock with specific characteristics. It is properly defined on the basis...

The Terminology of a Fold

folds, Tectonic, Terminology 8:58 PM

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<br />
<b>Amplitude</b> Half the height of the structure measured from crest to trough<br />
<br />
<b>Arc length </b>The distance between two hinges of the same orientation measured over the folded surface<br />
<br />
<b>Axial surface </b>The surface containing the hinge lines from consecutive folded surfaces<br />
<br />
<b>Crest</b> The topographically highest point of a fold, which need not coincide with the fold hinge<br />
<br />
<b>Cross section</b> A vertical plane through a fold<br />
<br />
<b>Culmination</b> High point of the hinge line in a noncylindrical fold<br />
<br />
<b>Cylindrical fold </b>Fold in which a straight hinge line parallels the fold axis; in other words, the folded surface wraps partway around a cylinder<br />
<br />
<b>Depression</b> Low point of the hinge line in a noncylindrical fold<br />
<br />
<b>Fold axis</b> Fold generator in cylindrical folds<br />
<br />
<b>Hinge</b> The region of greatest curvature in a fold<br />
<br />
<b>Hinge line</b> The line of greatest curvature<br />
<br />
<b>Inflection point</b> The position in a limb where the sense of curvature changes<br />
<br />
<b>Limb </b>Less curved portion of a fold<br />
<br />
<b>Noncylindrical fold</b> Fold with a curved hinge line<br />
<br />
<b>Profile plane</b> The surface perpendicular to the hinge line<br />
<br />
<b>Trough</b> The topographically lowest point of a fold, which need not coincide with the fold hinge<br />
<br />
<b>Wavelength</b> The distance between two hinges of the same orientation<br />
<br />
<a href="http://www.geologyin.com/2015/02/types-of-folds-with-photos.html" target="_blank"><span style="font-size: large;">Types of folds with Photos</span></a><br />
<br /></div>

The Terminology of a Fold

Amplitude Half the height of the structure measured from crest to trough Arc length The distance between two hinges of the same orie...

Magmatic processes

Magma, volcano 8:27 PM

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<br />
<div class="MsoNormal">
A quick review of the steps needed to make a magmatic rock…</div>
<h1 style="mso-list: l1 level1 lfo1; text-indent: 0cm;">
<span style="font-size: large;">I.<span style="font-stretch: normal; font-weight: normal;">     
</span><span dir="LTR"></span>Melting</span></h1>
<ul style="margin-top: 0cm;" type="disc">
<li class="MsoNormal">Is
     always partial (5-50 %), there is therefore a solid residuum (95-50 %).<o:p></o:p></li>
<li class="MsoNormal">Melting
     of the mantle generates basalt or andsites; melting of the crust generates
     granites.</li>
</ul>
<div class="MsoNormal">
Melt needs to be extracted from the partially molten system.</div>
<h1 style="mso-list: l1 level1 lfo1; text-indent: 0cm;">
<span style="font-size: large;">II.<span style="font-stretch: normal; font-weight: normal;"> 
</span><span dir="LTR"></span>Magma evolution: fractional
crystallization</span></h1>
<div class="MsoNormal">
As the system cools down, the magma evolves in the
“solid+liquid” field, between solidus and liquidus.<o:p></o:p></div>
<div class="MsoNormal">
<br /></div>
<ul style="margin-top: 0cm;" type="disc">
<li class="MsoNormal"><st1:city w:st="on">Crystals</st1:city> are
     progressively formed, and can settle down at the bottom of the “magma
     chamber”.<o:p></o:p></li>
<li class="MsoNormal">The
     remaining magma chemically evolves. Its evolution is a “mirror” image of
     the crystals removed: typically towards SiO2-rich, mafic poor composition.<o:p></o:p></li>
<li class="MsoNormal">Studying
     the exact shape of the liquid evolution trends allows to discuss which
     minerals where removed from the liquid.<o:p></o:p></li>
</ul>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
Three main trends of evolution:<o:p></o:p></div>
<ul style="margin-top: 0cm;" type="disc">
<li class="MsoNormal">Basalts
     evolve towards high-SiO2.<o:p></o:p></li>
<ul style="margin-top: 0cm;" type="circle">
<li class="MsoNormal">Undersaturated
      basalts remain so, and move in the undersaturated field, towards olivine-
      or nepheline-normative rocks (i.e., alkali series).<o:p></o:p></li>
<li class="MsoNormal">Saturated
      basalts remain so and evolve towards quartz-normative rocks
      (basalts-andesite-dacite-rhyolite, aka BADR series) (sub-alkaline
      series).<o:p></o:p></li>
</ul>
<li class="MsoNormal">Granites
     are already SiO2 rich… and remain so (little or no evolution)</li>
</ul>
<h1 style="mso-list: l1 level1 lfo1; text-indent: 0cm;">
<span style="font-size: large;">III.<span style="font-stretch: normal; font-weight: normal;">    </span><span dir="LTR"></span>Magma transfert and emplacement</span></h1>
<div class="MsoNormal">
Magma moves upwards through the crust; mafic magmas can be
seen to move through dyke swarms. The equivalent for granitic magma is not
seen.</div>
<h2 style="mso-list: l1 level2 lfo1; text-indent: 0cm;">
<span style="font-size: small;">A.<span style="font-stretch: normal; font-weight: normal;">  
</span><span dir="LTR"></span>Plutons and batholiths</span></h2>
<div class="MsoNormal">
If the magmas emplace at depth (typically, crustal magmas),
they fill small pockets = plutons, with rocks slowly crystallizing at depth.
Plutons are typically found as clusters of several to many intrusions
(batholiths), corresponding to successive magma inputs, typically during a
small time period.</div>
<h2 style="mso-list: l1 level2 lfo1; text-indent: 0cm;">
<span style="font-size: small;">B.<span style="font-stretch: normal; font-weight: normal;">  
</span><span dir="LTR"></span>Volcanoes</span></h2>
<div class="MsoNormal">
If the magma reaches surface (more common for mantle-derived
rocks), they erupt as volcanoes. The roots of the volcanoes are also dykes (but
localized below the actual volcanic vent).</div>
<h1 style="mso-list: l1 level1 lfo1; text-indent: 0cm;">
<span style="font-size: large;">IV.<span style="font-stretch: normal; font-weight: normal;">   </span>Cooling and sub-solidus
evolution</span></h1>
<div class="MsoNormal">
As the magma finally cools, it evolves from its liquidus at
900° (granites) to 1200° (basalts) down temperature towards cooler conditions:
the solid magmatic rocks starts its life in the amphibolite facies (typically)
and cools down to greenschist, therefore making (retrograde) metamorphic
evolution possible.</div>
</div>

Magmatic processes

A quick review of the steps needed to make a magmatic rock… I. Melting Is always partial (5-50 %), there is therefore a...

Two Brilliant Tourmalines on Cleavelandite Blades

Minerals 1:59 PM

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<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;"><tbody><tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-jqKWKYfkwcY/V8WZbO9DSGI/AAAAAAAAJf8/sGQAA-g1HCUvhYjEN0GzauZFcYzGWgsagCLcB/s1600/Gorgeous%2Bspecimen%2Bfeaturing%2Btwo%2Bbrilliant%2BTourmalines%2Bon%2BCleavelandite%2Bblades%2521.jpg" style="margin-left: auto; margin-right: auto;"><img alt="Two Brilliant Tourmalines on Cleavelandite Blades" border="0" height="398" src="https://1.bp.blogspot.com/-jqKWKYfkwcY/V8WZbO9DSGI/AAAAAAAAJf8/sGQAA-g1HCUvhYjEN0GzauZFcYzGWgsagCLcB/w400-h398/Gorgeous%2Bspecimen%2Bfeaturing%2Btwo%2Bbrilliant%2BTourmalines%2Bon%2BCleavelandite%2Bblades%2521.jpg" title="Two Brilliant Tourmalines on Cleavelandite Blades" width="400" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;">  <b><span style="font-family: "georgia" , "times new roman" , serif;">The Mineral Gallery, Inc.</span></b></td></tr></tbody></table><div class="separator" style="clear: both; text-align: center;">
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</div>
<b><span style="font-family: "georgia" , "times new roman" , serif;">Gorgeous specimen featuring two brilliant Tourmalines on Cleavelandite blades!</span></b><br />
<br />
The largest Tourmaline is mostly red but changes over to a greenish color just below where it touches the Cleavelandite. The termination at top is perfect and the sides are incredibly glassy and lustrous! The surface striations leap out at you as you roll the specimen from side to side. The smaller companion Tourmaline to the left is a mix of red and green coloration but also has a full termination. This is one of the prettiest California Tourmaline combos that I've seen recently and there is no damage to the tips.<br />
<br />
<b><span style="font-family: "georgia" , "times new roman" , serif;">From </span></b>the Himalaya Mine, Mesa Grande District, San Diego County, California.<br /><br />
Ex. Martin Zinn, K. Ward Mineral Collections<br />
<br /><br /></div>

Two Brilliant Tourmalines on Cleavelandite Blades

The Mineral Gallery, Inc. Gorgeous specimen featuring two brilliant Tourmalines on Cleavelandite blades! The largest Tourmaline i...

Origin of moon's 'ocean of storms' revealed

moon, News 9:36 PM

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<tr><td style="text-align: center;"><img border="0" src="http://1.bp.blogspot.com/-pbL8Go8ULkk/VJ7559MzfoI/AAAAAAAADUQ/N6vTSrzdOMQ/s1600/141001133024-large.jpg" height="320" style="margin-left: auto; margin-right: auto;" width="320" /></td></tr>
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<i style="background-color: #eeeeee;">A topographic map of the Moon (low elevations in purple, high in red) shows extensive lava flows in Oceanus Procellarum. New data from the GRAIL spacecraft suggests the region was formed by ancient volcanic activity, not by a large impactor as had long been suspected. The image was rendered by Jay Dickson from Brown University with data from NASA's Lunar Reconnaissance Orbiter and Lunar Orbiting Laster Altimeter.</i></div>
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<a href="http://1.bp.blogspot.com/-pbL8Go8ULkk/VJ7559MzfoI/AAAAAAAADUQ/N6vTSrzdOMQ/s1600/141001133024-large.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><span style="font-family: inherit;"></span></a></div>
<span style="font-family: inherit;"><br /></span>
<span style="font-family: inherit;"><br /></span>
<span style="font-family: inherit;"><br /></span>
<div style="background-color: white; color: #070809; line-height: 15.6000003814697px; padding: 5px 0px;">
<span style="font-family: inherit;">The new study, based on data from NASA's GRAIL mission, found a series of linear gravitational anomalies forming a giant rectangle, nearly 1,600 miles across, running beneath the Procellarum region. Those anomalies appear to be the remnants of ancient rifts in the Moon's crust, say the authors of the new study. The rifts provided a vast "magma plumbing system" that flooded the region with volcanic lava between 3 and 4 billion years ago. That giant flux of lava solidified to form the dark basalts we see from Earth.</span></div>
<div style="background-color: white; color: #070809; line-height: 15.6000003814697px; padding: 5px 0px;">
<span style="font-family: inherit;">It's the shape of the underlying gravity anomalies that cast doubt on impact hypothesis, said Jim Head, the Louis and Elizabeth Scherck Distinguished Professor of Geological Sciences at Brown and one of the authors of the new paper.</span></div>
<div style="background-color: white; color: #070809; line-height: 15.6000003814697px; padding: 5px 0px;">
<span style="font-family: inherit;">"Instead of a central circular gravity anomaly like all other impact basins, at Procellarum we see these linear features forming this huge rectangle," Head said. "This shape argues strongly for an internal origin and suggests internal forces."</span></div>
<div style="background-color: white; color: #070809; line-height: 15.6000003814697px; padding: 5px 0px;">
<span style="font-family: inherit;">The research team, led by Jeffrey Andrews-Hanna of the Colorado School of Mines, suggests a new hypothesis for just what those internal forces may have been. The process, the researchers believe, was driven by the geochemical composition of the Moon's crust in the Procellarum region.</span></div>
<div style="background-color: white; color: #070809; line-height: 15.6000003814697px; padding: 5px 0px;">
<span style="font-family: inherit;">Early in its history, the Moon is believed to have been entirely covered in molten magma, which slowly cooled to form the crust. However, the Procellarum region is known to have a high concentration of uranium, thorium, and potassium -- radioactive elements that produce heat. The researchers believe those elements may have caused Procellarum to cool and solidify after the rest of the crust had already cooled. When Procellarum did finally cool, it shrank and pulled away from the surrounding crust, forming the giant rifts seen in the new data. Magma flowed into those rifts and flooded the region.</span></div>
<div style="background-color: white; color: #070809; line-height: 15.6000003814697px; padding: 5px 0px;">
<span style="font-family: inherit;">"We think this is a really good, testable alternative to the impact basin theory," said Head. "Everything we see suggests that internal forces were critical in the formation of Procellarum."</span></div>
<div style="background-color: white; color: #070809; line-height: 15.6000003814697px; padding: 5px 0px;">
<strong><span style="font-family: inherit;">New mission, old debate</span></strong></div>
<div style="background-color: white; color: #070809; line-height: 15.6000003814697px; padding: 5px 0px;">
<span style="font-family: inherit;">The familiar face of the Moon's near side is dominated by the lunar maria, the dark patches etched across the surface. Most of the large circular features -- like Mare Serenitatis (Sea of Serenity) and Mare Imbrium (Sea of Rains) -- have been shown to be impact basins that later filled with volcanic lava, which eventually cooled to form the dark basalts. Samples gathered during the Apollo missions, and data gathered by subsequent unmanned missions, helped to confirm that idea.</span></div>
<div style="background-color: white; color: #070809; line-height: 15.6000003814697px; padding: 5px 0px;">
<span style="font-family: inherit;">But the origin of Oceanus Procellarum remained up in the air, largely because it simply doesn't look like the known basins. It is shaped a bit like a horseshoe, while the other basins are round. Procellarum also lacks surrounding mountains and radial grooves scoured by impact ejecta, both telltale signs of an impact basin.</span></div>
<div style="background-color: white; color: #070809; line-height: 15.6000003814697px; padding: 5px 0px;">
<span style="font-family: inherit;">Still, the idea that Procellarum was indeed formed by an impact surfaced in the mid-1970s. Proponents of the impact theory argued that Procellarum looked different simply because it was much older than the other basins. Because of its age, the telltale mountains and grooves had been eroded away, and debris had partially filled the basin's midsection, giving it the horseshoe shape.</span></div>
<div style="background-color: white; color: #070809; line-height: 15.6000003814697px; padding: 5px 0px;">
<span style="font-family: inherit;">Finally settling the debate required a mission like GRAIL, Head said. The mission is led by Maria Zuber, who earned her Ph.D. at Brown and is now vice president of research at MIT. The twin GRAIL spacecraft, which orbited the Moon in 2012, made detailed maps of the Moon's gravity. Those maps have revealed important details about the Moon's subsurface crust.</span></div>
<div style="background-color: white; color: #070809; line-height: 15.6000003814697px; padding: 5px 0px;">
<span style="font-family: inherit;">"It's like putting the crust under an X-ray," Head said. "We can go into the subsurface and see what's there. And when you're looking at what could be very old features, that's what you have to do because signatures at the surface become degraded over time."</span></div>
<div style="background-color: white; color: #070809; line-height: 15.6000003814697px; padding: 5px 0px;">
<span style="font-family: inherit;">Apollo 15 Commander David R. Scott, a visiting professor in the Department of Earth, Environmental, and Planetary Sciences at Brown, explored the Hadley-Apennine region at the edge of the Imbrium basin in 1971. "Orbiting the Moon following our surface exploration, it was very clear that Oceanus Procellarum differed in many ways from the circular maria in terms of its volcanic and tectonic activity," said Scott, who was not involved in this latest research. "After so many years of puzzling over this, GRAIL has now provided the data to show why it is so distinctly different."</span></div>
<div style="background-color: white; color: #070809; line-height: 15.6000003814697px; padding: 5px 0px;">
<span style="font-family: inherit;">Head said the results from this study show the remarkable extent to which internal processes can alter the surface of a planetary body. The data generated here will be helpful in understanding the evolution of other planets and moons, and aid in the continuing exploration of our own Moon.</span></div>
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Origin of moon's 'ocean of storms' revealed

A topographic map of the Moon (low elevations in purple, high in red) shows extensive lava flows in Oceanus Procellarum. New data from t...

Geologic Time Scale: Major Eons, Eras, Periods and Epochs

Chronostratigraphic, Earth History, edu, Geology 9:05 PM

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<span style="font-family: "georgia" , "times new roman" , serif;">The geologic time scale is an essential tool for understanding the history of Earth and the evolution of life. In this article , explore the principal eons, eras, periods, and epochs that help us track major events in geologic history.</span></div>
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<span style="font-family: "georgia" , "times new roman" , serif;">The Geologic Time Scale</span></h4>
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How do we know when the dinosaurs died out? How do we know when birds first appeared on Earth or when humans evolved? What about the beginning of life itself? How was our planet formed and populated by living things over time?<br />
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To answer these questions, geologists use a special timeline called the Geologic Time Scale. It's a record of the earth's geologic history as scientists have come to understand it by studying the layers in rock. The geologic time scale is broken up into larger and smaller subdivisions, which help us get a better sense of how historical events fit together. So, in this lesson, we're going to learn how the time scale was created and how its major subdivisions fit together to tell the story of Earth's history.</div>
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<span style="font-family: "georgia" , "times new roman" , serif;">Study of Strata</span></h4>
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People have been studying earth and rock formations for a very long time. In the 19th century, geologists took a closer look at the layers that they saw in sedimentary rocks. They noticed that the rock tended to lie in horizontal sections that had different colors, textures, and fossils inside. The top rock layer might have been limestone containing lots of snail fossils. </div>
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The next layer may have been chunky conglomerate rock, while the next was a layer of shale and fish fossils. Geologists called these layers of different rock types strata. They studied rock strata all around the world in order to figure out major events in geologic history. Over time, geologists and other scientists put all that information together to make the geologic time scale.</div>
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<span style="font-family: "georgia" , "times new roman" , serif;">Timeline Divisions</span></h4>
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Before we learn the parts of the geologic time scale, let's first talk about how we measure time in our own daily lives. For instance, how do you measure the time it takes to get ready for work or school? Do you measure it in minutes? Hours? Seconds? Days? Chances are you probably measure in minutes. Minutes are fine for measuring daily chores, like driving to an appointment, fixing dinner, or doing the laundry. </div>
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But what if you're talking about a bigger chore, like training for a marathon? You probably plan out your preparation on the scale of days, hours, weeks, and months. We measure our age in terms of years. We measure generations in terms of decades. And when we look at human history, we talk about it in terms of hundreds and thousands of years.<br />
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Obviously, it doesn't make sense to talk about everything on the same time scale. That's why we've broken up our time. Years are made up of months, months are made up of weeks, weeks are made up of days, and so on. Geologists use the very same strategy to talk about the history of the earth. They break up geologic time into larger and smaller chunks, so that major events are easier to talk about. Okay, now let's go ahead and check out the major divisions of the geologic time scale.<br />
Eons and Eras<br />
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The first principal subdivision is called the eon. An eon, the largest division of the geologic time scale, spans hundreds to thousands of millions of years. Geologists generally agree that there are two major eons: the Precambrian eon and the Phanerozoic eon. The Precambrian goes from the formation of the earth to the time when multicellular organisms first appeared - that's a really long time - from 4,500 million years ago to just about 543 million years ago. Then begins the Phanerozoic eon, which continues up to today.<br />
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Eons are made up of eras, divisions that span time periods of tens to hundreds of millions of years. The three major eras are the Paleozoic, the Mesozoic, and the Cenozoic. The Cenozoic era is the one we are in today. It began 65 million years ago, right about the time that the dinosaurs went extinct.<br />
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Keep in mind that these three eras are all grouped within the Phanerozoic eon. Remember that other eon, the Precambrian eon? Well, that one doesn't get to have any eras inside it. We don't have a lot of information about it, so we leave it as one big chunk in geologic history.</div>
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<span style="font-family: "georgia" , "times new roman" , serif;">Period and Epoch</span></h4>
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Period is one of several subdivisions of geologic time enabling cross-referencing of rocks and geologic events from place to place.<br />
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These periods form elements of a hierarchy of divisions into which geologists have split the earth's history.<br />
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An Epoch is a subdivision of the geologic timescale that is longer than an age and shorter than a period. We are currently living in the Holocene Epoch of the Quaternary Period. Rock layers deposited during an epoch are called a series. Series are subdivisions of the stratigraphic column that, like epochs, are subdivisions of the geologic timescale. Like other geochronological divisions, epochs are normally separated by significant changes in the rock layers they correspond to.<br />
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Epochs are most commonly used for the younger Cenozoic Era, where a greater collection of fossils has been found and paleontologists have more detailed knowledge of the events that occurred during those times. They are less commonly referred to for the other eras and eons, since less fossil evidence exists that allows us to form a clearer view of those time periods.</div>
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<span style="font-family: Georgia, "Times New Roman", serif;"><a href="https://www.geologyin.com/2016/12/10-interesting-facts-about-geological.html" target="_blank">10 Interesting Facts About the Geological Time Scale</a></span></div>
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Geologic Time Scale: Major Eons, Eras, Periods and Epochs

Geologic Time Scale: Major Eons, Eras, Periods and Epochs The geologic time scale is an essential tool for understanding the history o...

Magma plumbing found buried below moon's largest dark spot

Magma, moon, News 12:41 PM

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<span style="font-family: inherit; font-size: x-small;"><i style="background-color: #eeeeee;">Buried rift features, detected through gravity mapping, are seen superimposed on a full moon.</i></span></div>
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Scientists have found a nearly square peg underneath a round hole—on the moon. Several kilometers below Oceanus Procellarum, the largest dark spot on the moon’s near side, scientists have discovered a giant rectangle thought to be the remnants of a geological plumbing system that spilled lava across the moon about 3.5 billion years ago. The features are similar to rift valleys on Earth—regions where the crust is cooling, contracting, and ripping apart. Their existence shows that the moon, early in its history, experienced tectonic and volcanic activity normally associated with much bigger planets.<br />
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“We’re realizing that the early moon was a much more dynamic place than we thought,” says Jeffrey Andrews-Hanna, a planetary scientist at the Colorado School of Mines in Golden and lead author of a new study of the Procellarum’s geology. The discovery also casts doubt on the decades-old theory that the circular Procellarum region is a basin, or giant crater, created when a large asteroid slammed into the moon. “We don’t expect a basin rim to have corners,” Andrews-Hanna says.<br />
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The work is based on data gathered by GRAIL (Gravity Recovery and Interior Laboratory), a pair of NASA spacecraft that orbited the moon in 2012. Sensitive to tiny variations in the gravitational tug of the moon, GRAIL mapped density variations below the surface (because regions of higher density produce slightly higher gravitational forces). Below known impact basins, GRAIL found the expected ringlike patterns, but underneath the Procellarum region, the mysterious rectangle emerged. “It was a striking pattern that demanded an explanation,” Andrews-Hanna says.<br />
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Scientists already know that the Procellarum region is rich in radioactive elements that billions of years ago would have produced excess heat. The study team theorizes that as this region cooled, the rock would have cracked in geometrical patterns, like honeycomb patterns seen on Earth in basalt formations, but on a much larger scale. In a study published today in Nature, the researchers propose that these cracks eventually grew into rift valleys, where magma from the moon’s mantle welled up and pushed apart blocks of crust. Lava spilled out and paved over the Oceanus Procellarum, creating the dark spot that is seen today. The extra weight of this dense material would have caused the whole region to sink slightly and form the topographic low that has made the Procellarum seem like a basin.<br />
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With the discovery, the moon joins Earth, Mars, and Venus as solar system bodies with mapped examples of rifting. There are also similar features near the south pole of Enceladus, the moon of Saturn that is spewing water into space from cracks in an ice shell.<br />
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Andrews-Hanna and colleagues have made a good case, says Herbert Frey, a planetary scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, even though the newly described features are surprising. The moon is not big enough to have the same strong convective cooling process that Earth has in its interior, he explains, and ordinarily convection is one of the main mechanisms thought to lead to large-scale rifting. So just what caused the rifting remains unclear. “It just means the moon continues to surprise us,” he says. Frey adds that a remaining mystery is why the rectangular features were found only beneath Oceanus Procellarum. Even if the rifting is explained by the excess radioactive elements, there is still no definitive explanation for why only the near side of the moon ended up enriched.<br />
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The discovery could also be a death knell for the impact theory for Oceanus Procellarum, an idea first put forth in the early 1970s. A basin there would have been the largest on the moon—larger than the South Pole–Aitken Basin—and second in the solar system only to the Borealis Basin on Mars, which covers the planet’s entire northern hemisphere.<br />
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Ryosuke Nakamura, a researcher at the National Institute of Advanced Industrial Science and Technology in Tsukuba, Japan, is still not convinced that an impact can be ruled out. In 2012, he and his colleagues published a paper in Nature Geoscience that found compositional evidence for an impact within Procellarum—a type of pyroxene mineral that is found in other, known impact basins such as South Pole–Aitken and is associated with the melting or excavation of mantle rock from an asteroid impact.<br />
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In response to the current study, Nakamura says that the features in the southwestern corner of the Procellarum region look to be circular rather than rectangular, and still consistent with an impact. But Frey, who has long been skeptical of the impact theory, says that the features are as clear as day, and not what you’d expect underneath a basin. “That looks like a rectangle to me.”<br />
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Magma plumbing found buried below moon's largest dark spot

Buried rift features, detected through gravity mapping, are seen superimposed on a full moon. Scientists have found a nearly squ...

Mantle plumes crack continents

Earth News 9:45 PM

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<span style="background-color: #eeeeee;"><i>In some parts of the Earth, material rises upwards like a column from the boundary layer of Earth's core and the lower mantle to just below Earth's crust hundreds of kilometres above.</i></span></div>
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<strong><span style="font-family: inherit;">Are mantle plumes responsible for the African rift system?</span></strong></div>
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<span style="font-family: inherit;">Geologists believe that plumes are not just responsible for creating volcanoes outside of tectonically active areas -- they can also break up continents. The scientists offer the Danakil Depression (the lowlands in the Ethiopia-Eritrea-Djibouti triangle) as an example of this. This "triple junction" is extremely tectonically and volcanically active. Geologists believe that the so-called Afar plume is rising up below it and has created a rift system that forks into the Red Sea, the Gulf of Aden and Africa's Great Rift Valley. However, the sheer length of time required, geologically speaking, for this process to take place, means that nobody is able to confirm or disprove with absolute certainty that the force of a plume causes continental breakup.</span></div>
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<strong><span style="font-family: inherit;">Simulations becoming more realistic</span></strong></div>
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<span style="font-family: inherit;">Evgueni Burov, a Professor at the University of Paris VI, and Taras Gerya, Professor of Geophysics at ETH Zurich, have now taken a step closer to solving this geological mystery with a new computer model. Their paper has recently been published in the journal <em>Nature</em>. The two researchers conducted numerical experiments to reproduce the Earth's surface in high-resolution 3D.</span></div>
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<span style="font-family: inherit;">These simulations show that the rising flow of material is strong enough to cause continental breakup if the tectonic plate is under (weak) tensile stress. "The force exerted by a plume on a plate is actually too weak to break it up," says Gerya. In experiments using simple models, the researchers allowed the plumes to hit an unstressed plate, which did not cause it to break, but merely formed a round hump. However, when the geophysicists modelled the same process with a plate under weak tensile stress, it broke apart, forming a crevice and rift system like the ones found around the world.</span></div>
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<span style="font-family: inherit;">"The process can be compared to a taut piece of plastic film. Weak, pointed force is enough to tear the film, but if the film is not pulled taut, it is extremely difficult to tear." This mechanism has already been proposed in the past as a possible model for explaining continental breakup, but had never been outlined in plausible terms before now.</span></div>
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<strong><span style="font-family: inherit;">First high-resolution simulations</span></strong></div>
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<span style="font-family: inherit;">"We are the first to create such a high-resolution model which demonstrates how a plume interacts with a plate under tensile stress," says Gerya. Fast and powerful computers and stable algorithms programmed by the scientists themselves were required for the simulations. The researchers benefited from technical advances made and experience accumulated by the ETH professor in this field over the past ten years.</span></div>
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<span style="font-family: inherit;">In the model, the deformations are created quickly from a geological point of view. Rift systems several kilometres deep and more than a thousand kilometres long can form after "just" two million years. The processes are therefore up to ten times faster than tectonic processes such as subduction and 50 times faster than the Alpine orogeny, for example.</span></div>
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<strong><span style="font-family: inherit;">Disputed idea</span></strong></div>
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<span style="font-family: inherit;">The idea of mantle plumes is widely disputed, with some researchers denying that they even exist. "I think it is much more likely that they do exist," says Gerya. As is often the case in geology, especially when researching Earth's interior, such processes and phenomena like the existence of plumes cannot be observed directly. Furthermore, the periods over which geological processes take place are far too long for humans to experience first-hand. "So far, we have only been able to observe the effects that plumes have on the Earth's surface and on the propagation of seismic waves in the Earth's interior."</span></div>
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<span style="font-family: inherit;">The scientists are therefore reliant on good, realistic models that show the processes in a geological time lapse. How realistic the calculated simulations are depends on the parameters used. The plume-plate interaction model incorporated physical laws, the characteristics of materials in the Earth's crust and mantle, and temperature and pressure conditions. "We know the rules, but humans generally lack the intuition to identify how they interact on geological timescales."</span></div>
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The above story is based on <a href="http://www.eurekalert.org/pub_releases/2014-09/ez-mpc090414.php" rel="nofollow" style="color: #004276; outline-offset: 0.2em; outline: red dotted 0.2em !important; text-decoration: none;" target="_blank">materials</a> provided by <a class="blue" href="http://www.ethz.ch/index_EN" rel="nofollow" style="color: #7e7ea9; outline-offset: 0.2em; outline: red dotted 0.2em !important; text-decoration: none;" target="_blank"><strong>ETH Zurich</strong></a>. <em>Note: Materials may be edited for content and length.</em></div>
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Mantle plumes crack continents

In some parts of the Earth, material rises upwards like a column from the boundary layer of Earth's core and the lower mantle to jus...

Gas leaks from faulty wells linked to contamination in some groundwater

climate, Groundwater, News 9:34 PM

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<i style="background-color: #eeeeee;">As researchers study hydraulic fracturing, a team led by Thomas Darrah at The Ohio State University has identified a key source of groundwater contamination  caused by faulty well casings.</i></div>
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<span style="font-family: inherit;">A team led by a researcher at The Ohio State University and composed of researchers at Duke, Stanford, Dartmouth, and the University of Rochester devised a new method of geochemical forensics to trace how methane migrates under the earth. The study identified eight clusters of contaminated drinking-water wells in Pennsylvania and Texas.</span></div>
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<span style="font-family: inherit;">Most important among their findings, published this week in the <em>Proceedings of the National Academy of Sciences</em>, is that neither horizontal drilling nor hydraulic fracturing of shale deposits seems to have caused any of the natural gas contamination.</span></div>
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<span style="font-family: inherit;">"There is no question that in many instances elevated levels of natural gas are naturally occurring, but in a subset of cases, there is also clear evidence that there were human causes for the contamination," said study leader Thomas Darrah, assistant professor of earth sciences at Ohio State. "However our data suggests that where contamination occurs, it was caused by poor casing and cementing in the wells," Darrah said.</span></div>
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<span style="font-family: inherit;">In hydraulic fracturing, water is pumped underground to break up shale at a depth far below the water table, he explained. The long vertical pipes that carry the resulting gas upward are encircled in cement to keep the natural gas from leaking out along the well. The study suggests that natural gas that has leaked into aquifers is the result of failures in the cement used in the well.</span></div>
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<span style="font-family: inherit;">"Many of the leaks probably occur when natural gas travels up the outside of the borehole, potentially even thousands of feet, and is released directly into drinking-water aquifers" said Robert Poreda, professor of geochemistry at the University of Rochester.</span></div>
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<span style="font-family: inherit;">"These results appear to rule out the migration of methane up into drinking water aquifers from depth because of horizontal drilling or hydraulic fracturing, as some people feared," said Avner Vengosh, professor of geochemistry and water quality at Duke.</span></div>
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<span style="font-family: inherit;">"This is relatively good news because it means that most of the issues we have identified can potentially be avoided by future improvements in well integrity," Darrah said.</span></div>
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<span style="font-family: inherit;">"In some cases homeowner's water has been harmed by drilling," said Robert B. Jackson, professor of environmental and earth sciences at Stanford and Duke. "In Texas, we even saw two homes go from clean to contaminated after our sampling began."</span></div>
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<span style="font-family: inherit;">The method that the researchers used to track the source of methane contamination relies on the basic physics of the noble gases (which happen to leak out along with the methane). Noble gases such as helium and neon are so called because they don't react much with other chemicals, although they mix with natural gas and can be transported with it.</span></div>
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<span style="font-family: inherit;">That means that when they are released underground, they can flow long distances without getting waylaid by microbial activity or chemical reactions along the way. The only important variable is the atomic mass, which determines how the ratios of noble gases change as they tag along with migrating natural gas. These properties allow the researchers to determine the source of fugitive methane and the mechanism by which it was transported into drinking water aquifers.</span></div>
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<span style="font-family: inherit;">The researchers were able to distinguish between the signatures of naturally occurring methane and stray gas contamination from shale gas drill sites overlying the Marcellus shale in Pennsylvania and the Barnett shale in Texas.</span></div>
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<span style="font-family: inherit;">The researchers sampled water from the sites in 2012 and 2013. Sampling sites included wells where contamination had been debated previously; wells known to have naturally high level of methane and salts, which tend to co-occur in areas overlying shale gas deposits; and wells located both within and beyond a one-kilometer distance from drill sites.</span></div>
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<span style="font-family: inherit;">As hydraulic fracturing starts to develop around the globe, including countries South Africa, Argentina, China, Poland, Scotland, and Ireland, Darrah and his colleagues are continuing their work in the United States and internationally. And, since the method that the researchers employed relies on the basic physics of the noble gases, it can be employed anywhere. Their hope is that their findings can help highlight the necessity to improve well integrity.</span></div>
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The above story is based on <a href="http://news.osu.edu/news/2014/09/15/gas-leaks-from-faulty-wells-linked-to-contamination-in-some-groundwater/" rel="nofollow" style="color: #004276; outline-offset: 0.2em; outline: red dotted 0.2em !important; text-decoration: none;" target="_blank">materials</a> provided by <a class="blue" href="http://www.osu.edu/" rel="nofollow" style="color: #7e7ea9; outline-offset: 0.2em; outline: red dotted 0.2em !important; text-decoration: none;" target="_blank"><strong>Ohio State University</strong></a>. The original article was written by Pam Frost Gorder. <em>Note: Materials may be edited for content and length.</em></div>
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Gas leaks from faulty wells linked to contamination in some groundwater

As researchers study hydraulic fracturing, a team led by Thomas Darrah at The Ohio State University has identified a key source of groun...

Turbulence in molten core helps amplify Earth's magnetic field

Earth News, Geology 9:24 PM

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<span style="background-color: #eeeeee; font-family: inherit; font-size: xx-small;">Image of the 'Derviche Tourneur Sodium' experiment. The outer stainless steel sphere (in the center of the image) contains a smaller inner sphere (or core) made of copper. 40 liters of liquid sodium are enclosed between the two spheres. The ratio of the radii of the two spheres is identical to that between the Earth's inner core and the core-mantle boundary. By analogy, the sodium therefore represents the liquid outer core.</span></div>
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<i>Researchers have shown that turbulence, random motion that takes place in the molten metal in the Earth's core, makes a contribution to our planet's magnetic field. To obtain this result, they modeled the Earth's outer core using liquid sodium enclosed between two rotating concentric metal spheres. Like many planets and most stars, the Earth produces its own magnetic field by dynamo action, i.e. because of the motion of an electrically conducting fluid-in this case, a mixture of molten iron and nickel.</i><br />
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<span style="font-family: inherit;">Like many planets and most stars, Earth produces its own magnetic field by dynamo action, i.e. because of the motion of an electrically conducting fluid-in this case, a mixture of molten iron and nickel. This ocean of liquid metal, the outer core, surrounds the inner core, which is made of solid metal. It is set in motion by the convection caused by the cooling of the core. The resulting flow is particularly complex: in addition to movement of fluid over long distances, which is well understood and generates a magnetic field, there are also turbulent fluctuations, involving erratic, random motion over short distances. Although turbulence also exists in the atmosphere and the oceans, the turbulence in Earth's core is different, since it is under the combined influence of Earth's rotation and of a strong magnetic field. It is not currently possible to reproduce this distinctive turbulence either by laboratory experiments or by computer simulations<sub><sup>.</sup></sub><sup>2</sup> Until now, it was therefore impossible for geophysicists to determine its role with regard to the magnetic field.</span></div>
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<span style="font-family: inherit;">In order to better understand the interactions between turbulence and the magnetic field, researchers at the Institut des Sciences de la Terre, in Grenoble, used the Derviche Tourneur Sodium experiment, begun in 2005. In this miniature model of Earth's core, 40 litres of liquid sodium (an electrically conducting fluid) is enclosed in the space between two concentric spheres. What makes this model unique is that a magnet in the center of the inner sphere provides a strong magnetic field, while the rotation of this core drives the flow of the conducting liquid very effectively. Under these conditions, the liquid sodium is subjected to a strong magnetic field and to fast rotation, as would be expected in Earth's core, and undergoes both large-scale motion and random fluctuations.</span></div>
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<span style="font-family: inherit;">Sensors placed around the outer sphere and inside the sodium were used to map the magnetic field, while ultrasound beams measured the rate of flow of the fluid using the Doppler effect. The data enabled the researchers to show that turbulent motion increases the fluid's ability to conduct electricity and therefore amplifies the magnetic field, rather than reducing it as earlier experiments had appeared to show. This phenomenon, observed for the first time in the laboratory, was confirmed by numerical simulations.</span></div>
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<span style="font-family: inherit;">The findings also apply to planets with a magnetic field and to stars. The discovery of this new component of the magnetic field may explain why in the case of Venus, Earth's 'twin' planet, the liquid metal core does not produce a magnetic field. Closer to home, a better understanding of these turbulent fluctuations could help us to understand magnetic field reversals.</span></div>
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<span style="font-family: inherit;">(1) Refers to the members of the Sufi order, the whirling dervishes ('derviches tourneurs' in French), who perform a whirling dance.</span></div>
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<span style="font-family: inherit;">(2) A complete numerical simulation of the motions taking place in the outer core would make it necessary to cover a wide range of scales with a very small time step, which is out of reach with current capabilities.</span></div>
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<span style="font-family: inherit; font-size: x-small;"><u><i>The above story is based on <a href="http://www2.cnrs.fr/en/2485.htm" rel="nofollow" style="color: #004276; outline-offset: 0.2em; outline: red dotted 0.2em !important; text-decoration: none;" target="_blank">materials</a> provided by <a class="blue" href="http://www.cnrs.fr/index.php" rel="nofollow" style="color: #7e7ea9; outline-offset: 0.2em; outline: red dotted 0.2em !important; text-decoration: none;" target="_blank"><strong>CNRS</strong></a>. Note: Materials may be edited for content and length.</i></u></span></div>
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Turbulence in molten core helps amplify Earth's magnetic field

Image of the 'Derviche Tourneur Sodium' experiment. The outer stainless steel sphere (in the center of the image) contains a sma...

Geology In