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Lower Cretaceous limestones, especially those of the Edwards Group, are seen in road cuts along Interstate Highway 10 west of San Antonio. Near Kerrville (Exit 508) and Junction, "shoaling-upward cycles ... include subtidal, highly burrowed facies passing up into higher energy intertidal grainstones. This sequence is capped by supratidal, commonly stratiform dolomite with gypsum nodule molds, local de-dolomite and erosional truncation. These cycles are typically meter-scale, and the dolomites can reasonably be interpreted as products of penecontemporaneous sabkha processes." Brian E. Lock, and Jamsie L. Roberts, "Sedimentological Features Within the Edwards Group of West-Central Texas," Gulf Coast Association of Geological Societies Transactions, Vol. XLIX 1999, p. 310. |
 Click for Larger View. Group takes closer look at shoaling upward cycles in I-10 road cut. (KB)  Click for Larger View. Stratiform dolomite (dark lithology), well defined beds, mile 501, north side of west bound I-10 lanes. (BW) | ||
 Click for Larger View. Solution joint. (BW)  Click for Larger View. Stromatolite (arrow) and chert nodules (below). (BW) | ||
 Click for Larger View. Closer view of chert nodules above. (KB)  Click for Larger View. Trace fossils. (BW) | ||
 Click for Larger View. Chert layer (black). (BW)  Click for Larger View. Parallel laminations in grainstone, bioturbation, disrupted bedding. (BW) | ||
 Click for Larger View. Herringbone x-beds in grainstone. (BW)  Click for Larger View. Parasequence boundary. (BW) |
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