Minerals allogenic

Chamosite appears to be the finest grained and most abundant mineral in this group. It occurs in lateritic clay deposits (Brindley, 1951), both as oolites and matrix in sedimentary ironstones (Hallimond, 1925), in hydrothermal deposits (Ruotsala et al., 1964), in shales (Drcnnan, 1963), in Recent shallow-marine deposits (Porrenga, 1966) and in estuarine sediments (Rohrlich et al., 1969). It is probable that chamosite is more abundant than commonly realized however, Drennan (1963) has pointed out that it is extremely unstable in a leached and oxidized environment and is not likely to persist as an allogenic mineral. 

Classification based on idealized compositional components in the sediment organic (elements bound to organic matter) sorbed (elements sorbed to particle surfaces) Fe-Mn oxide (elements bound to or within oxides), lattice (= mineral-bound, elements contained within the structure of allogenic rock-forming mineral). 

Allogenic Sediment component(s) formed outside the lake specifically refers to rock, mineral, and organic particles that were derived form pre-existing materials, eroded and transported to the depositional site. 

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