Max Meadows Fault Breccia

The fault breccia along the Max Meadows overthrust in the Draper Mountain area, Virginia, consists of three cataclastic zones: an upper autoclastic breccia composed of large, angular blocks and smaller tabular fragments of quartz sericite phyllite; a lower autoclastic zone consisting of angular blocks and fractured masses of Elbrook limestone and dolomite; and an intervening zone of crush conglomerate composed chiefly of rounded fragments of limestone, dolomite, and phyllite. Contacts of the upper and lower breccias with contiguous wall rocks are gradational. Crush conglomerate, which grades into the autoclastic breccias above and below, was formed by mingling, crushing, and rolling out of parts of the autoclastic breccias. The crush-conglomerate zone contains fragments of several types of rocks which are not found in the adjacent autoclastic breccias. These must have been acquired down the original dip of the Max Meadows fault surface where it cuts Lower Cambrian and pre-Cambrian rocks. Parts of the Max Meadows fault breccia have been squeezed into fractures of the rocks on both sides of the fault zone and occur in the form of dikes of crush conglomerate. Of the several modes of origin discussed, only strictly tectonic processes could have produced the breccias and crush conglomerate occurring along or near the Max Meadows fault in this area.