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Late Pleistocene
The Late Pleistocene, also known as the Upper Pleistocene or Tarantian, is the final division of the Pleistocene Epoch, from 129,000 to 11,700 years ago.
Late veneer
The late veneer is chondritic meteoritic material that geochemical models add to Earth's mantle after core formation, explaining why highly siderophile elements like platinum remain abundant there.
Lateral connectivity
Lateral connectivity is the water-mediated exchange of water, energy, materials, and organisms between a river channel and its floodplain, one of three dimensions of river connectivity.
Laterite
Laterite, or lateritic soil, is a highly weathered tropical soil or rock rich in iron and aluminum oxides, a major source of nickel and a traditional building brick.
Latite
Latite is a volcanic rock made of roughly equal alkali feldspar and sodic plagioclase with little or no quartz, making it the extrusive equivalent of monzonite.
Latitude
Latitude is the geographic coordinate specifying a point's north–south position on Earth as an angle from 0° at the Equator to 90° at the poles, running east–west as parallels.
Laura Slivinski
Laura Slivinski is an American applied mathematician at NOAA's Physical Sciences Laboratory in Boulder, Colorado, known for co-leading the 20th Century Reanalysis version 3 weather reconstruction.
Laura Tobin
Laura Tobin is an English broadcast meteorologist who trained with the Met Office and has presented the weather on ITV's Good Morning Britain since 2014.
Laurentia
Laurentia, the North American craton, is the ancient geological core of North America, assembled by 1.7 billion years ago and including Greenland and northwest Scotland until the Late Cretaceous.
Lava
Lava, also known as volcanic lava, is molten rock erupted onto a planet's surface, called magma underground, that cools into igneous rock, forming flow types such as pāhoehoe and ʻaʻā.
Lava dome
A lava dome, also called a volcanic dome, is a steep-sided mound formed when viscous lava piles up over its vent instead of flowing away.
Lava lake
A lava lake is a persistent body of molten lava at the top of a volcano's magma column, kept molten by convection for years to decades.
Lava tube
A lava tube, also known as a lava tunnel or pyroduct, is a cave formed when lava's surface hardens into a roof and the molten interior drains away.
Lead line (nautical)
A lead line, also called a sounding line, is a marked rope with a lead weight used for centuries to measure water depth and sample the seabed.
Leaf litter breakdown
Leaf litter breakdown is the decomposition of dead leaves in streams and rivers through leaching, microbial conditioning, and fragmentation, a key energy source for aquatic food webs.
Leak detection and repair
Leak detection and repair (LDAR) is a regulatory practice in which oil and gas facilities are surveyed for methane leaks, typically with infrared cameras, and leaks are repaired within mandated deadlines.
Leaking underground storage tank program
The leaking underground storage tank (LUST) program is the US federal and state program for cleaning up petroleum and hazardous releases from underground storage tanks.
Least-squares migration
Least-squares migration (LSM) is a seismic imaging method that iteratively inverts a forward modeling operator to produce images with fewer artifacts, truer amplitudes, and higher resolution than conventional migration.
Lee cyclogenesis
Lee cyclogenesis, also called orographic cyclogenesis, is the development of a cyclone on the downwind side of a mountain range, such as the Alps or Rockies.
Lee wave
A lee wave is a quasi-stationary atmospheric gravity wave that forms on the downwind side of a mountain range, often visible as stationary lenticular clouds.
Lee-Lueng Fu
Lee-Lueng Fu is a Taiwanese-American physical oceanographer at NASA's Jet Propulsion Laboratory who led satellite altimetry missions measuring sea level, including TOPEX/Poseidon and SWOT, and was elected to the National Academy of Engineering in 2008.
Leeville
Leeville is a shaft-accessed underground gold mine on the Carlin Trend in northern Nevada, near Elko. It was Newmont's first Nevada underground mine reached by shaft, producing ore from 2006.
Length of day variations
Length of day variations are millisecond changes in the Earth's actual rotation relative to the standard 86,400-second day, driven by tides, atmospheric winds, the liquid core, and climate change.
Lepidocrocite
Lepidocrocite is an iron oxide hydroxide mineral, FeO(OH), dimorphous with goethite, that forms as a secondary oxidation product in soils, ore deposits, and rust layers on carbon steel.
Lepidolite
Lepidolite is a lithium-rich mica mineral, usually pink, red, or purple, that occurs almost exclusively in lithium-enriched granitic pegmatites and serves as a minor ore of lithium.
Lessivage
Lessivage, also called argilluviation, is the transfer of fine clay particles, chiefly under 2 μm, from a soil's eluviated E-horizon to a deeper B-horizon, producing the clay-enriched horizons of Luvisols.
Level of free convection
The level of free convection (LFC) is the altitude at which a lifted parcel of air first becomes warmer than its environment and can rise on its own buoyancy.
Lhasa terrane
The Lhasa terrane is a continental fragment that makes up southern Tibet and was the last crustal block to accrete to Eurasia before India collided with it.
Lidar bathymetry
Lidar bathymetry is a remote sensing method that maps shallow seafloor depth by firing green laser pulses from aircraft, reaching roughly 50 m in clear coastal water.
Lifted condensation level
The lifted condensation level (LCL) is the altitude at which a rising unsaturated air parcel cools to saturation and condensation begins, used to estimate convective cloud bases.