Taxonomy term

usgs

Comment: National Geological Surveys: The past, present and future

The oldest national geological survey (Britain’s) is 183 years old; the youngest (China’s) is 19. Yet all the surveys share commonalities. A symposium last June in Vancouver, British Columbia, examined where surveys have been and where they’re going.

06 Dec 2018

Mineral Resource of the Month: Phosphate

Phosphate rock refers to unprocessed ore and beneficiated concentrates that contain some form of apatite, a group of calcium phosphate minerals. Apatite in phosphate rock is the primary source for phosphorus in phosphate fertilizers. More than 80 percent of the world’s current production of phosphate rock is mined from sedimentary deposits, which were formed by the deposition of phosphate-rich materials in marine regions. Most of the rest comes from igneous deposits of carbonatites and silica-deficient intrusions. The grade of phosphate rock is classified by the phosphorus pentoxide content.

23 Oct 2018

Down to Earth With: Volcanologist Scott Rowland

When Scott Rowland returned to his home on Oahu after earning a bachelor’s degree in geology at Oregon State University, intent on heading to graduate school, he was torn between studying volcanoes or groundwater. Ultimately, he chose to study Hawaii’s basalt lavas as a graduate student at the University of Hawaii at Manoa.

14 Aug 2018

Mineral Resource of the Month: Tin

The main source of tin is cassiterite (SnO2), a tin oxide mineral; cassiterite has been the primary source of tin throughout history. Most of the world’s identified tin resources occur as placer deposits, a large number of which are located along the Southeast Asian tin belt. The remaining resources occur as hydrothermal hard-rock veins. In the United States, tin deposits are rare; there are no known extensive tin placer deposits and the few hard-rock deposits are currently not economically exploitable.

12 Aug 2018

Mineral Resource of the Month: Chromium

Although chromium is a metal, it does not occur naturally in metallic form. Chromium can be found in many minerals, but the only economically significant chromium-bearing mineral is chromite. Chromite has been mined from four different deposit types: stratiform chromite, podiform chromite, placer chromite, and laterite deposits. Most of the world’s resources, however, are located in stratiform chromite deposits, such as the Bushveld Complex in South Africa. The economic potential of chromite resources depends on the thickness and continuity of the deposit and on the grade of the ore. Many of the major stratiform chromite deposits also contain economic levels of platinum, palladium, rhodium, osmium, iridium and ruthenium.

13 Jun 2018

Mineral Resource of the Month: Sulfur

Sulfur is one of the few elements found in elemental form in nature and has been used in elemental form since ancient times. It forms near volcanic vents and fumaroles, and small quantities of native sulfur form during the weathering of sulfate and sulfide minerals. However, the largest concentrations of sulfur are found associated with sulfide ore mineral deposits and with evaporative minerals in salt domes. As the 16th-most abundant element in Earth’s crust, sulfur is plentiful and can be found around the world.

 
12 Apr 2018

Mineral Resource of the Month: Titanium

Titanium is the ninth-most abundant element in Earth’s crust and is found in nearly all rocks and sediments, although it is not found as a pure metal in nature. It has a strong affinity for oxygen, typically forming oxide minerals — the most important being ilmenite and rutile. Processing of ilmenite and rutile in shoreline (beach) and fluvial (river and stream) heavy mineral sand deposits — found along many continental margins — provides most of the world’s titanium supply. Most of the remaining supply comes from two large hard rock deposits that contain ilmenite.

 
05 Feb 2018

Mineral Resource of the Month: Zinc

Zinc is a ubiquitous element occurring in many rocks in Earth’s crust and as a trace constituent in the oceans and the atmosphere. Zinc is commonly found in mineral deposits along with other base metals, such as copper and lead, and is produced mainly from three types of deposits: sedimentary exhalative, Mississippi Valley type, and volcanogenic massive sulfide. Sphalerite, a zinc sulfide mineral, is the primary ore mineral for zinc and has been the source for most of the world’s production.

 

04 Dec 2017

Troubled waters: Lead lurking in U.S. water supplies

In 2014, Flint, Mich., started drawing its drinking water from the highly corrosive Flint River, which leached lead from old pipes, exposing the population to lead poisoning. Such aging infrastructure exists in towns across the nation, leaving many to wonder if what happened in Flint could happen to them. The answer in many cases is yes.
30 Oct 2017

Mineral Resource of the Month: Strontium

Two strontium-bearing minerals, celestite (strontium sulfate, SrSO4) and strontianite (strontium carbonate, SrCO3), contain strontium in sufficient quantities to make recovery practical. Celestite occurs much more frequently and is the primary source of the world’s supply of strontium. Celestite occurs as crystals and as massive or fibrous aggregates in sedimentary rocks. It often displays a delicate blue color owing to the presence of impurities. Celestite can occur in bedded evaporite deposits in conjunction with gypsum, anhydrite and halite. It can also occur in cavities within carbonate rocks where it is precipitated from strontium-bearing groundwaters or brines.

 
02 Oct 2017

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