| OCR Text |
Show Quartz Extinction Types In all four thin the most abundant. and. ps sections, quartz with straight extinction is Undulose extinction is the next most abundant, small percentage is composite a.nd a serrdcomposite. If we accept the conclusions of Blatt and Christie 577) no useable provence information (1968, results·. However, sembledge is indicative of This fits the Folk which from a it is or but may definitely possible that high grade metamorphic we source that such too much an as source area. eraphas Ls to minority according in the are from these be obtained metamorphic give count and estimated conglomerate pebble Of course, are 71) suggests igneous an megascopic data, igneous.rocks, p. can (1963, to the percentages in the tilloid. looking at material derived tha. t included much recrJStallized quartz, but proof of this idea. is lacking. Size Distribution thin·sections, In two of the to 1/4-rrlllimeter fraction (see the size mode is in the In the other fraction. the cumUlative curves, and the Inclusive two, figure it is 16). 1/8th in the silt Sorting is poor, Graphic Standard Deviation (Folk, 1968, p. 46) ranges within the interval from 1.0 to 2.0. Sandstone Composition point Fork Formation (see rather than the Sample five counts of three sandstones in the Mineral table 1) indicate that variability is the rule exception. was taken from a sandstone lens in tilloid (unit I . |
