Deep earth

Characteristics of Deep - Earth Anhydrous Fluids Learnings from Archean Au Deposits... 

Fig. 1. Anhydrous fluids, oxidized and reduced, are intrinsic to mineral systems, originating in the deep-Earth.

Williams, Q. Hemley, R.J. 2001. Hydrogen in the deep Earth. Annual Reviews Earth Planetary Science, 29, 365-418. 

Gold, T. and Soter, S. (1980). The deep-earth-gas hypothesis. Scientific American 242,154-161. 

Radon occurs in deep earth gases. Many products are emitted continuous-... 

This was the central belief of alchemy. If metals may indeed be interconverted one to another in the deep earth, perhaps the alchemist could find a way to accelerate the process artificially and make gold from baser metals. But how was this done ... 

Microorganisms have been found growing at depths of 2.8-4.2 km beneath the land surface (Pedersen 1993 Fyfe 1996 Kerr 1997). Microbes at 4.2 km grow at a temperature of 110°C. Temperature, rather than pressure, is probably the most important growth-limiting factor for deep-earth microbes (Pedersen 1993 Fyfe 1996). Organic biopolymers and complex cellular structures tend to be destroyed at elevated temperatures, and apparently elevated metabolism and cellular repair activity does not compensate for the rates at which critical bonds are broken hence, cells cannot repair thermal damage beyond a point. 

Stoffler D. (1997) Minerals in the deep Earth a message from the asteroid belt. Science 278, 1576-1577. 

Porcehi D., Cassen P., Woolum D., and Wasserburg G. J. (1998) Acquisition and early losses of rare gases from the deep Earth. In Origin of the Earth and Moon, LPI Contribution No. 597. Lunar and Planetary Institute, Houston, pp. 35-36. 

Porcehi D., Cassen P., and Woolum D. (2001) Deep Earth rare gases initial inventories, capture from the solar nebula and losses during Moon formation. Earth Planet. Set Lett 193,... 

CaSiOs perovskite has enormous storage potential for lithophile elements. Its ability to host uranium and thorium make it an especially important phase to understand with respect to long-term storage of these heat-producing elements in the deep Earth. 

Knittle E. and Williams Q. (1995) Static compression of c-EeSi and an evaluation of reduced silicon as a deep Earth constituent. Geophys. Res. Lett. 22, 445-448. 

Lay T., Williams Q., and Garnero E. J. (1998) The coremantle boundary layer and deep Earth dynamics. Nature 392, 461-468. 

It is critical to clarify the fluid flow picture during HP-LT metamorphism since subduction of sediment and hydrothermally altered oceanic crust and mantle is the primary means by which reactive volatiles including H2O and CO2 are returned to the deep Earth, ultimately giving rise to arc magma genesis at —100-150 km depth... 

An outstanding question is how much of the mantle still maintains high volatile concentrations. This involves resolution of the nature of the high He/" He OIB-source region. Most models equate this with undepleted, undegassed mantle, although some models invoke depletion mechanisms. However, none of these has matched the end-member components seen in OIB lithophile isotope correlations. It remains to be demonstrated that a primitive component is present and so can dominate the helium and neon isotope signatures in OIB. The heavy-noble-gas characteristics in OIB must still be documented. It is not known to what extent major volatiles are stored in the deep Earth and associated with these noble gas components. 

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