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river water, major constituents

river water, major constituents  

The average composition of river water is very different from that of sea water. The pH varies greatly from areas of high organic activity, e.g. the equatorial rain forests, to zones of little ...
Amazonian

Amazonian  

A division of areological time, lasting from 1.80 Gy to the present in the Hartmann–Tanaka Model and 3.55 Gy to the present in the Neukum–Wise Model, and divided into three epochs: Lower Amazonian ...
nanoplankton

nanoplankton  

Marine planktonic organisms 2.0–20 μm in size.
sea state

sea state  

A system for the classification of average wave height, with a scale that ranges from 0 to 9.wave height (m)statedefinition00calm, glassy0–0.11calm, ...
femtoplankton

femtoplankton  

Marine planktonic organisms, 0.02–0.2μm in size, about which little is known.
chrysocolla

chrysocolla  

A hydrated silicate of copper, with the formula CuSiO2.2H2O; sp. gr. 2.0; hardness variable; greenish-blue; variable lustre; normally forms from the weathering of copper-rich mineral deposits, and ...
kaersutite

kaersutite  

A member of the alkali amphiboles with the composition (Na,K)Ca2(Mg,Fe)4Ti[Si6Al2O22](OH)2 in a group which includes katophorite Na(Na,Ca)(Mg,Fe2+)4Fe3+[Si7AlO22] (OH)2 and oxyhornblende NaCa2(Mg,Fe, ...
water velocity

water velocity  

The velocity (v m/s) of sound waves in water is dependent on temperature (T °C) and salinity (S parts per thousand), and can be calculated for any depth (Z) using the formula v = 1449 + 4.6T - ...
International Gravity Formula

International Gravity Formula  

Formula used to determine the gravitational acceleration at a given latitude (gϕ) for a model of the Earth that comprises a rotating, oblate spheroid. gϕ= g0(1 + α sin2 ϕ + β sin2 ϕ), where g0 is the ...
stilpnomelane

stilpnomelane  

A phyllosilicate (sheet silicate) similar to biotite with the formula (K,Na,Ca)0–1.4 (Fe2+,Fe3+,Mg,Al,Mn)5.9–8.2 [Si8O20] (OH)4(OH,F)3.6–8.5; sp. gr. 2.59–2.96; hardness 3.0–4.0; properties similar ...
glaucophane

glaucophane  

An important alkali amphibole of composition Na2(Mg3Al2)[Si8O22](OH)2, and end-member of the glaucophane–riebeckite (Na2(Fe2+3Fe3+2)[Si8O22](OH)2 series; sp. gr. 3.0; hardness 6.0; blue, ...
ΔT method

ΔT method  

In seismic investigations, a method of velocity analysis associated with the normal moveout correction (ΔT), which enables the root-mean-square velocity (vrms) to be calculated down to a particular ...
westward drift

westward drift  

The apparent westward motion of features of the geomagnetic field (mostly the non-dipole component) with time, estimated to be about 0.2° of longitude per year during the last 100 years.
Kaena

Kaena  

A reversed polarity subchron which occurs at about 2.87 ± 0.03 Ma within the Gauss normal polarity chron.
reflection coefficient

reflection coefficient  

1 (R) The ratio of the amplitude of a reflected ray (A1) to that of the incoming ray (A0), such that R = A1A0. In the case of a normally incident ray, R can be expressed in terms of the acoustic ...
flakiness index

flakiness index  

The specification for stone for bituminous surfacing, applied to aggregate coarser than 6.5 mm. It is expressed as the percentage by weight of particles (in a sample of more than 200) whose smallest ...
Schwassmann–Wachmann 3

Schwassmann–Wachmann 3  

A comet with an orbital period of 5.35 years; perihelion date 2 June 2006; perihelion distance 0.933 AU.
thermal infrared

thermal infrared  

Infrared radiation which has a wavelength between 3.0 μm and 100 μm. At normal environmental temperatures objects emit infrared between these wavelengths; hotter objects, such as fires, emit infrared ...
gravity unit

gravity unit  

Not an official SI unit, but one commonly used to measure gravitational acceleration. One gravity unit is equal to 10-6 m/s2, or 0.1 mgal.
K-index

K-index  

In geomagnetism, the maximum values for the horizontal intensity (H) and the declination (tan-1 X/Y), each on a range 0 to 9, for a three-hourly interval.

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