Geology and mineralogy

Bet Meir or Amminadav Formation

The Bet Meir or Amminadav Formation is a disputed name for Early Cenomanian platey limestones at the 'Ein Yabrud quarries in the West Bank, Palestine.

Oct 20, 2026

Bezymianny

Bezymianny (Безымянный), an andesitic stratovolcano (2,882 m) in Kamchatka's Klyuchevskoy group, Russia; considered extinct until its catastrophic 1956 directed-blast eruption, now continuously rebuilding its lava dome with frequent explosive eruptions.

Bingham Canyon Mine

The Bingham Canyon Mine, known locally as the Kennecott Copper Mine, is a giant open-pit copper mine near Salt Lake City, Utah, and the largest man-made excavation on earth.

Biocrust

A biocrust, short for biological soil crust, is a community of cyanobacteria, lichens, mosses, and other organisms binding the top millimeters of soil, especially in drylands.

Bioerosion

Bioerosion is the removal of hard substrate such as rock, limestone, and coral carbonate by the direct action of organisms, through boring, grazing, etching, and dissolution.

Biostratigraphy

Biostratigraphy, also called biocorrelation, is the branch of stratigraphy that organizes rock strata by their fossil content into units called biozones, chiefly to correlate rocks of the same age.

Biotite

Biotite, also known as black mica, is the group name for dark, iron-rich mica minerals occurring widely in igneous and metamorphic rocks such as granite and gneiss.

Bioturbation

Bioturbation is the reworking of soils and sediments by living organisms through particle mixing and bioirrigation, a process Charles Darwin first quantified in his 1881 study of earthworms.

Biozone

A biozone is a body of strata defined by its fossil content, the fundamental unit of biostratigraphy, rooted in William Smith's law of faunal succession.

Birimian Greenstone Belt

The Birimian Greenstone Belt is a set of 2.2 to 2.0 billion-year-old rock belts in West Africa, named after the Birim River in Ghana and rich in gold.

Birnessite

Birnessite is a hydrous layered manganese oxide mineral, first described in 1956 from Birness, Aberdeenshire, Scotland, and common in soils, desert varnish, and marine manganese nodules.

Birthstone

A birthstone is a gemstone assigned to a person's month of birth, worn as jewelry or given as a gift; the modern American list was standardized in 1912.

Black shale

Black shale is a dark mudrock rich in organic matter and pyrite, defined by more than 1% total organic carbon, that can generate oil and natural gas.

Blagodatnoye

Blagodatnoye is a large open-pit gold mine in the Severo-Yeniseisk district of Krasnoyarsk Territory, Russia, operated by PJSC Polyus. Commissioned in July 2010, it is Polyus' third largest mine.

Blancan

The Blancan is a North American land mammal age spanning most of the Pliocene, named for Mt. Blanco, Texas, and defined by the first appearance of voles.

Oct 20, 2026

Blanco, Cerro

Cerro Blanco (Robledo) is a 4,670 m Holocene caldera in Catamarca, Argentina, source of the Central Andes' largest Holocene eruption (~4.2 ka, >100 km3 tephra), now slowly subsiding with an active blind geothermal field.

Blueschist facies

The blueschist facies, introduced by Pentti Eskola in 1920 as the glaucophane-schist facies, describes low-temperature, high-pressure metamorphism in subduction zones, producing blue schists rich in glaucophane and lawsonite.

Bluestone

Bluestone is the trade name in the dimension stone industry for blue-gray, fine-grained igneous rock of basaltic composition, quarried in Victoria, Australia since the 1830s for buildings, kerbs, and laneways.

Bobcaygeon Formation

The Bobcaygeon Formation is a Middle Ordovician limestone formation in southern Ontario, defined by B.A. Liberty in 1969 and named after the town of Bobcaygeon.

Boddington Gold Mine

The Boddington Gold Mine is a large open-pit gold and copper mine near Boddington, Western Australia, operated by Newmont and one of Australia's largest gold producers.

Bog iron

Bog iron, also called bog iron ore, is impure iron oxyhydroxide deposit formed in bogs and swamps, historically the main iron ore of Northern Europe.

Bora-Bericha-Tullu Moye

Bora-Bericha-Tullu Moye (BBTM) is an active silicic volcanic complex of three edifices and nested calderas in the central Main Ethiopian Rift, Ethiopia, last erupting about 1900 CE, with geothermal development and over 27 explosive eruptions in 100,000 years.

Borden Mine (Ontario)

Borden Mine is an underground gold mine near Chapleau in northern Ontario, Canada, which reached commercial production in October 2019 as Canada's first underground mine mostly powered by battery-electric vehicles.

Bornite

Bornite is a copper iron sulfide mineral, Cu5FeS4, and an important ore of copper, best known for the iridescent blue and purple tarnish called "peacock ore."

Oct 20, 2026

Boset

Boset (Boset-Bericha, Boseti) is a twin stratovolcano complex (Gudda and Bericha) in the northern Main Ethiopian Rift, 17 x 20 km, summit 2,447 m, caldera formed after ~120 ka, with Holocene explosive eruptions including the ~600-year-old Boset Pumice.

Bottino

Bottino (Miniera del Bottino) is a historic lead-silver mine at Stazzema in the Apuane Alps, Tuscany, Italy. Worked from the Middle Ages, reopened by Cosimo I de' Medici in 1542, industrially developed in the 19th century, and definitively closed in 1969.

Boulder field

Boulder field: a geomorphic term for boulder-covered landforms of glacial or periglacial origin, including block fields (felsenmeer), glacial till, and talus slopes; mostly Pleistocene relicts, 50,000–10,000 years old, that can persist through multiple glacial cycles.