Petrography and Origin of Krol Sandstones Around Solon, Northwestern Himalaya, India: ABSTRACT

Abstract

The area around Solon (lat. 30° 55^prime; long. 77° 07^prime) in northwestern sub-Himalaya, India, is the type area of the Krol Group (Permo-Carboniferous?). Petrologically the the Krol sandstones may be designated as coarse- to medium-grained sandstone: mature quartz and carbonate-cemented quartz arenite (Folk, 1966). Conspicuous presence of round grains of quartz led earlier workers to conceive of an origin for these sandstones. Petrologic examination of the sandstone End_Page 835------------------------------ shows moderate amounts of different sedimentary rock fragments, no relation between size and roundness, and different degrees of roundness in the same size grade. All these features indicate the possibility of their derivation from preexisting rocks. To resolve the problem of origin of roundness, i.e., eolian versus inherited, size analyses of the rounded and well-rounded grains, assumed to represent the airborne fraction, yield a mean size of 0.466 ^phgr. This value does not correspond to the size of the airborne load, as specified by Bagnold, nor does it correspond to the grain-size characteristics of the bimodal sands that are residuum in the process. Thus the roundness of the Krol sandgrains is not from action but is caused by the derivation of the sand grains fr m preexisting sandstone. In addition to the presence of glauconite, their close association with intraclastic, oolitic, and pelletiferous carbonate rocks indicates a shallow-marine origin for these sandstone beds. End_of_Article - Last_Page 836------------