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Latest Petrology Stories

Study Shows Extrusive Volcanism Formed Hawaiian Islands
2013-10-07 09:17:25

A recent study changes the understanding of how the Hawaiian Islands formed. Scientists have determined that it is the eruptions of lava on the surface, extrusion, which grow Hawaiian volcanoes, rather than internal emplacement of magma, as was previously thought.

Mud Volcano Island Rises From Sea After Pakistani Earthquake
2013-09-26 14:22:20

A powerful earthquake that struck the southwestern province of Baluchistan, Pakistan Tuesday afternoon, killing hundreds of people, has given rise to a new island off the coast of the country's Gwadar Port.

New Sourcing Technique Detects Obsidian In Seconds
2013-09-10 09:27:02

Obsidian is a naturally occurring volcanic glass with a smooth, hard surface. Obsidian is far sharper than a surgical scalpel when fractured, making it a highly desirable raw material for crafting stone tools for almost all of human history.

Supervolcanic Ash Can Transform Into Lava Miles Away From Eruption
2013-08-28 06:33:27

New research has taken a closer look at how ash produced from supervolcanoes can turn back into lava once it falls back to Earth.

Eruptions Not Always Imminent From Slow Magma
2013-08-20 04:41:19

A new modeling study from the University of Washington reveals reservoirs of silica-rich magma of the sort that causes the most explosive volcanic eruptions can persist for hundreds of thousands of years in the Earth’s upper crust without triggering an eruption.

Improved Eruption Forecasts May Come Via Costa Rican Volcano Study
2013-08-01 07:54:55

A new study, led by Columbia University's Lamont-Doherty Earth Observatory, suggests the 1960's eruption of Costa Rica's largest stratovolcano was triggered by magma rising from the mantle over a few short months, rather than thousands of years or more, as many scientists have thought.

2013-06-17 09:52:57

The noble gases get their collective moniker from their tendency toward snobbishness. The six elements in the family, which includes helium and neon, don't normally bond with other elements and they don't dissolve into minerals the way other gases do. But now, geochemists from Brown University have found a mineral structure with which the nobles deign to fraternize. Researchers led by Colin Jackson, a graduate student in geological sciences, have found noble gases to be highly soluble in...

Pebbles, Sand In Martian River Network Show Signs Of Ancient Water
2013-06-05 09:19:44

The most convincing evidence yet that the frigid deserts of Mars were once a habitable environment crossed by flowing water are presented by pebbles and sand scattered near an ancient Martian river network.


Latest Petrology Reference Libraries

Chaitén
2014-08-28 10:38:21

Chaitén is a volcanic caldera that is located in southern Chile that reaches an elevation of 3,681 feet. It is thought that this volcano once held a rhyolite obsidian lava dome that reached 3,156 in height, but this was destroyed after its most recent eruption in 2008. In the past, this volcano has released grey obsidian, which was used by pre-Columbian cultures to make many objects, some of which have been found 250 miles away from the volcano. Chaitén experienced the beginning of a new...

28_e9750264d5476c85f9be09d17bc6fd51
2005-05-26 12:03:39

Biotite is a common phyllosilicate mineral that contains potassium, magnesium, iron and aluminium. It is sometimes called "iron mica" and is found in granitic rocks, gneisses, and schists. Like other mica minerals, biotite has a highly perfect basal cleavage, its flexible sheets easily flaking off. It has a hardness of 2.5 - 3, a specific gravity of 2.7 - 3.1, is colored greenish to brown or black, and can be transparent to opaque. Biotite is occasionally found in large sheets, especially in...

28_56635877b282726a86b25cf3e98722c2
2005-05-26 11:30:45

Chert is a fine-grained silica-rich cryptocrystalline sedimentary rock that may contain small fossils. It varies greatly in color from white to black, but most often manifests as gray, brown, grayish brown and light green to rusty red; its color is an expression of trace elements present in the rock, and both red and green are most often related to traces of iron (in its oxidized and reduced forms respectively). It outcrops as nodules in limestone, chalk, and dolostone formations as a...

28_42121cee4c09c0898f52263bea588d54
2005-05-26 11:26:59

Chromite, iron magnesium chromium oxide: (Fe,Mg)Cr2O4, is an oxide mineral belonging to the spinel group. Magnesium is always present in variable amounts, also aluminium and iron substitute for chromium. Chromite is found in peridotite and other layered ultramafic intrusive rocks and also found in metamorphic rocks such as serpentinites. Ore deposites of chromite form as early magmatic differentiates. It is commonly associated with olivine, magnetite, serpentine, and corundum. Chromite is...

28_b760796d3dace508242e89fc53d49081
2005-05-26 11:13:08

In geology, a conglomerate is a rock consisting of other stones that have been cemented together. Conglomerates are sedimentary rocks consisting of subangular clasts and are thus differentiated from breccias, which consist of angular clasts. Both conglomerates and breccias are characterized by clasts larger than sand (>2 mm). There are two varieties of conglomerate, defined by texture: paraconglomerates and orthoconglomerates. Paraconglomerates are one of two varieties of conglomerate...

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Word of the Day
dwale
  • The deadly nightshade, Atropa Belladonna, which possesses stupefying or poisonous properties.
  • A sleeping-potion; a soporific.
  • To mutter deliriously.
The word 'dwale' comes from an Old English word meaning 'error, doubt, delusion.'
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