Figure 8. Photographs of middle Miocene sedimentary units in the Carlin basin. A: Thin andesite flow units underlain by ca. 15.1 Ma, ash-rich strata (white); sediments of the upper epiclastic unit (not shown) overlie the andesite. Faulting and tilting occurred after basin sedimentation. Photo taken looking north along the west side of the Adobe Range. B: Sand, pebbles, and cobbles in braided stream and channel deposits of the basal epiclastic member; hammer for scale. Photo taken east of the Cottonwood Gulch area in the northwestern part of the basin. C: Soft-sediment deformation in the ash-rich unit along the west side of the Adobe Range. The deformed bed is 1 m thick. D: Alternating fluvial, epiclastic sand beds and lacustrine ash-rich beds of the mixed epiclastic and ash-rich unit. The thick ash bed being sampled was deposited at 16.3 Ma. The underlying sand bed fills a 2-m–deep channel just to the right of the photo. Photo taken along upper Susie Creek in the northeastern part of the basin. E: Contact between the ash-rich unit (white) and the upper epiclastic unit (tan) along Interstate 80 west of Carlin. A tephra in the ash-rich unit near where the photo was taken produced a 14.7 Ma correlation age. The contact is conformable and, where exposed, sharp. F: The upper epiclastic unit (f) and a local zone of the underlying ash-rich unit (a, arrow), both of which overlie weathered and oxidized Paleozoic sedimentary rocks and the Gold Quarry gold deposit in the left side of the photo. The dashed white line delineates the sediment-bedrock contact. Photo taken looking north in the Gold Quarry mine on the west side of the Carlin basin.