Latest Petrology Stories
Materials deep inside Earth have unexpected atomic properties that might force earth scientists to revise their models of Earth's internal processes, a team of researchers has discovered.The researchers recreated in the lab the materials, crushing pressures and infernal temperatures they believe exist in the lowermost mantle, nearly 2,900 kilometers (1,800 miles) below Earth's surface. They report in the journal Nature Geoscience the materials exhibit rare and unexpected atomic properties...
Diamonds from Brazil have provided the answers to a question that Earth scientists have been trying to understand for many years: how is oceanic crust that has been subducted deep into the Earth recycled back into volcanic rocks? A team of researchers, led by the University of Bristol, working alongside colleagues at the STFC Daresbury Laboratory, have gained a deeper insight into how the Earth recycles itself in the deep earth tectonic cycle way beyond the depths that can be accessed by...
By Steinhoefel, Grit Hegner, Ernst; Oliver, Grahame J H Abstract: Major- and trace-element data and Nd isotope compositions for granitoid samples from the Grampian Highlands in Scotland show a systematic evolution in the composition of their sources in the course of the Caledonian Orogeny. Granitoids of 511- 451 Ma, related to the collision of the Midland Valley island arc with the Grampian terrane, show S-type affinity and fractionated REE patterns with minor Eu anomalies and low initial...
A linear string of mud pots and mud volcanoes suggest surface evidence for a southern extension of the San Andreas Fault that runs through the Salton Sea, according to a paper published in the August issue of the Bulletin of the Seismological Society of America (BSSA).Researchers David K. Lynch and Kenneth W. Hudnut of USGS report the results of a comprehensive survey of mud pots in the area immediately east of the southeastern-most portion of the Salton Sea in Imperial County, Calif. Using...
Aura Silver Resources Inc. (TSX VENTURE: AUU) (the "Company" or "Aura Silver") is pleased to announce Fugro Airborne Surveys is currently flying a GEOTEM(R) survey over the recently staked Greyhound Claim Group located in Nunavut, just north of the Hamlet of Baker Lake. Newly recorded claims, staked in the spring of 2008 more than double Aura's Greyhound land package (now totaling 23,000 hectares). The claims cover a relatively unexplored Archean greenstone belt and are wholly-owned by Aura...
Queensland Minerals Ltd. (TSX VENTURE: QML) (the "Company") announces a correction to its July 15, 2008 news release entitled "Queensland Minerals Update on Exploration Program Encouraging results from the Dingo Peak Copper-Gold discovery in North Queensland, Australia". A table detailing assay results of the Dingo Peak drillhole DHDD07 was inadvertently omitted from the release. Today's release reproduced the Dingo Peak portion of the July 15 news release with the assay results (see Table...
Sarissa Resources, Inc. ("the Company") (PINKSHEETS: SRSR) is pleased to announce the assay results from chip samples taken from the adit into the main D Zone deposit carried out in June, 2008, on its 100% owned Nemegosenda carbonatite project located in Northern Ontario. The results from all 15 samples taken and assayed confirm the presence of niobium mineralization, tantalum mineralization and rare earth elements ("REE") mineralization within the deposit. The samples were taken over a...
By Rakovan, John The very first Word to the Wise column dealt with the term pegmatite (Rakovan 2003). This was especially fitting because pegmatites are one of the most important rock types or geologic environments for the production of beautiful and interesting mineral specimens. A qualitative assessment of this can be made through a simple review of mineral journals, where one finds that tourmaline, aquamarine (often referred to as t&a), and other pegmatite minerals comprise a large...
Pro-Or (TSX VENTURE: POI) wishes to announce that exploration on its Quebec James Bay area Menarik property resumed on June 6, 2008. The resumption of exploration comes after the filing of a NI 43-101-compliant report prepared using the results from its Fall 2006 work program and the integration of previous work compilation datas. This compilation helped in defining four (4) types of mineralisation on the Menarik property. The property contains stratiform chromitites formations, massive...
Golden Chalice Resources Inc. (TSX-V: GCR) (PINKSHEETS: GCRIF) is pleased to announce that drilling on the Langmuir Nickel discovery continues to intersect high grade nickel mineralization. Also of great importance is that assay results from deep drilling confirm the presence of the same rocks and style of nickel mineralization as the Langmuir discovery. These results suggest the potential for one or multiple nickel mineralized zones in addition to the discovery. This is the first time...
Latest Petrology Reference Libraries
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...
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...
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...
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...
Diorite is a grey to dark grey intermediate intrusive igneous rock composed principally of plagioclase feldspar (typically andesine), hornblende, and/or pyroxene. Varieties deficient in hornblende and other dark minerals are called leucodiorite. It is often described as "salt and pepper" when composed largely of light-colored minerals randomly interspersed with dark minerals. When olivine and more iron-rich augite are present, the rock grades into ferrodiorite, which is transitional to...
![Chemistry of Martian Rock \"Esperance\"](/media/gallery/mars-exploration-rover-opportunity/thumbs/thumbs_pia17075.jpg "Chemistry of Martian Rock \\"Esperance\\"")
