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Pyrope
Pyrope is the magnesium-aluminum garnet, a blood-red gem mineral from mantle rocks such as kimberlite, known in the jewelry trade as the classic Bohemian garnet.
Pyrophyllite
Pyrophyllite is a soft hydrous aluminum silicate mineral with the formula Al2Si4O10(OH)2, similar to talc, named in 1829 for exfoliating into fan shapes when heated, and mined chiefly for refractories and ceramics.
Pyroxene
Pyroxene is the name of a group of dark rock-forming chain silicate minerals with formula XYZ₂O₆, abundant in igneous and metamorphic rocks and important in the Earth's upper mantle.
Pyrrhotite
Pyrrhotite is a non-stoichiometric iron sulfide mineral, Fe₁₋ₓS, whose iron vacancies make it magnetic; it is abundant in the crust and common in nickel and copper ores.
Q-vector
A Q-vector is a horizontal vector used in quasigeostrophic meteorology whose divergence appears in the omega equation, forcing synoptic-scale vertical velocity; Q-vector convergence implies ascent.
Qiangtang terrane
The Qiangtang terrane is a continental block in northern central Tibet, bounded by the Jinsha and Bangong-Nujiang suture zones, that drifted north from Gondwana as part of the Cimmerian continent.
Quantitative precipitation estimation
Quantitative precipitation estimation (QPE) converts radar, gauge, and satellite observations into precipitation rates and accumulations used in flash flood warning, hydrologic modeling, and data assimilation.
Quantitative precipitation forecast
A quantitative precipitation forecast (QPF) is a forecast of expected rainfall or snowfall, expressed as liquid water depth, over an area during a specific time window.
Quartz
Quartz, also known as rock crystal, is a crystalline mineral of silicon dioxide, abundant in igneous, metamorphic, and sedimentary rocks, famous for its purple amethyst variety.
Quartzite
Quartzite, also known as metaquartzite, is a hard, quartz-rich metamorphic rock formed when sandstone or chert recrystallizes under regional or thermal metamorphism; the name also covers some well-cemented sandstone.
Quasi-Biennial Oscillation
The quasi-biennial oscillation (QBO) is a quasi-periodic reversal of equatorial stratospheric winds averaging about 28 months, first detected in 1960 and among the most predictable atmospheric cycles.
Quasi-geostrophic theory
Quasi-geostrophic (QG) theory is a simplified system of equations for large-scale midlatitude atmospheric and oceanic flow, developed mainly by J. G. Charney in the late 1940s and still central to weather forecasting.
Quasistatic approximation
The quasistatic approximation is a geophysics modeling simplification that neglects inertial terms in the momentum balance, underpinning poroelastic consolidation, crustal deformation, ice-sheet flow, and atmospheric dynamics.
Quaternary
The Quaternary is the current geological period, covering the past 2.58 million years and defined by glacial cycles, human evolution, and the extinction of large mammals.
Quaternary glaciation
Quaternary glaciation: the ongoing ice age of the last 2.58 million years, marked by 41-kyr then ~100-kyr glacial–interglacial cycles, Northern Hemisphere ice sheets, the Mid-Pleistocene Transition at ~900 ka, and the current Holocene interglacial.
Quaternary Ice Age divisions
The Quaternary Ice Age divisions are the glacial and interglacial subdivisions of the Pleistocene, classically the four Alpine ice ages Günz, Mindel, Riss, and Würm.
Quetrupillan
Quetrupillan (Complejo Volcanico Quetrupillan) is a 2,360 m glacier-covered stratovolcano in Chile's Southern Volcanic Zone, between Villarrica and Lanin, with Holocene trachyte flank vents, last confirmed eruption 255 CE, in Villarrica National Park.
Quicksand
Quicksand, also known as sinking sand, is sand saturated with water so that it flows like a liquid; people sink only to about the waist.
QuikSCAT
QuikSCAT (Quick Scatterometer) was a NASA satellite carrying the SeaWinds scatterometer, which measured ocean surface winds from its launch in 1999 until an antenna failure in 2009.
Quimsachata-Oroscocha
Quimsachata-Oroscocha is a pair of monogenetic volcanoes in the Cusco Region of southern Peru; Quimsachata erupted about 11,500 years ago and Oroscocha about 6,400 years ago.
R/V Falkor
R/V Falkor was an 82.9-meter oceanographic research vessel operated by the Schmidt Ocean Institute from 2012 to 2022, converted from a German fisheries protection vessel and donated to Italy in 2022.
R/V Kaimei
R/V Kaimei (かいめい) is a Japanese seafloor wide-area research vessel built in 2016 and operated by JAMSTEC for broad, integrated surveys of the seafloor and strata beneath it.
R/V Meteor
R/V Meteor is a German multidisciplinary ocean research vessel, the third of three ships named Meteor, built in 1986 and owned by the Federal Republic of Germany.
R/V Mirai
R/V Mirai (みらい, "future") was a Japanese oceanographic research vessel of JAMSTEC, converted from the nuclear ship Mutsu, which completed 268 voyages from 1997 until retirement in 2025.
R/V Neil Armstrong
R/V Neil Armstrong (AGOR-27) is an American Ocean Class research vessel owned by the US Navy and operated by Woods Hole Oceanographic Institution from Woods Hole, Massachusetts.
R/V Polarstern
R/V Polarstern is a German research icebreaker operated by the Alfred Wegener Institute from Bremerhaven since 1982, working alternately in the Antarctic and Arctic and best known for the MOSAiC drift expedition.
R/V Roger Revelle
R/V Roger Revelle is a Global Class oceanographic research vessel owned by the U.S. Navy and operated by Scripps Institution of Oceanography, delivered in 1996 and named for the former Scripps director Roger Revelle.
R/V Sally Ride
R/V Sally Ride is a Navy-owned oceanographic research ship operated by Scripps Institution of Oceanography, delivered in 2016 and named for the first American woman in space.
R/V Sikuliaq
R/V Sikuliaq is a 261-foot, global-class oceanographic research vessel owned by the National Science Foundation and operated by the University of Alaska Fairbanks from Seward.
Race to Zero
Race to Zero was a United Nations-backed campaign, launched in 2020, rallying businesses, cities, investors, and institutions to halve emissions by 2030 and reach net zero by 2050.