3He is a so-called primordial isotope. It was made in the Big Bang and incorporated into Earth during its initial accretion and in the subsequent long-term acquisition of “late veneer” material. 3He is not produced in any large quantities by radiogenic decay, and is thus not being added to Earth’s inventory at a significant rate. Nevertheless, a small amount is constantly being added to the surface of the Earth by interplanetary dust particles [Anderson, 1993] and by cosmic rays. This so-called “cosmogenic” 3He may be important in rocks that have lain at the surface of the Earth for long periods. | Figure 1: Industrial helium is mostly 4He and is mined from helium mines |
R/HeliumNetwork: Powered by the Helium Blockchain, The People’s Network allows anyone to earn a new cryptocurrency, HNT, by building out a massive Press J to jump to the feed. Press question mark to learn the rest of the keyboard shortcuts. Denoted by the symbol R, the value of the gas constant is: R = 8.314472 (15) J K-1 mol-1 The two digits in parentheses indicate the uncertainty (standard deviation) in the last two digits of the value. Movement of particles (atoms, molecules, or ions) in the gas phase.
R Constant Of Helium
4He is a product of alpha decay of U and Th, and accumulates over time. This accumulation is most rapid in rocks that are rich in U+Th, but may be very slow in rocks that contain little U+Th. The U+Th content of mantle rocks and recycled material varies by 3 or 4 orders of magnitude and the opportunity therefore arises to develop large variations in 3He/4He ratios.
R Of Helium
The Earth is constantly degassing, which transports helium from the crust and mantle into the oceans and atmosphere. Because it is such a light atom, helium escapes from Earth and is thereby continually lost from the atmosphere. The approximate lifetime of helium in the atmosphere is ~ 1 to 2 Myr.
Three Uses Of Helium
The absolute abundance of helium in rocks is difficult to interpret since helium is so mobile. Thus, the 3He/4He ratio (R) is usually used as a proxy for 3He content. R is generally expressed as a multiple of the present-day atmospheric 3He/4He ratio, Ra, which is 1.38 x 10-6.
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