JMDMT #714 Microfossils of Cyanobacteria in Carbonaceous Meteorites

The James M. DuPont Meteorite Collection - products of igneous rocks. The montmorillonite minerals are known to occur both in soils and sediments and in rocks altered by hot hydrothermal solutions. Layer sihcate minerals occur under a rather wide range of temperatures. Magnetite is present in many igneous rocks (which crystallized from molten silicates), and in sediments. Epsomite is known to crystallize from (low temperature) mineral water; it is often found in limestone caves. Sulphur may be the result of either volcanic activity, of the decomposition of H2S in thermal springs or of bacterial action in rocks and Recent sediments. On the other hand, phase equilibria studies,"'*' have demonstrated that certain, characteristic high temperature minerals, absent in Orgueil, beg'n to form above 450 to 500°