Page 150 - Petrology of Sedimentary Rocks

The source area of calclithites must have had rugged relief, and the deposits are
laid down in alluvial fans and river channels (like the tectonic arkoses). Contempora-
neous faulting within a carbonate basin may produce marine calclithites and some
calclithites are turbidites (McBride). Maturity is variable, and conglomerates are very
frequent; in fact it appears that most calclithites are conglomerates. Consequently
deposits accumulate as large prisms and decrease rapidly outward in thickness. Most
calclithites (probably all) are cemented with calcite. They often contain rounded
quartz grains, fragments of angular chert, sandstone, or shales, and of course are
characterized by reworked fossils. Upon deeper erosion, basement rock may contribute
feldspar or MRF’s, and the rocks pass into arkoses or graywackes. Chert-arenites and
calclithites form under similar tectonic conditions, and the difference between them
may be partly due to climate and relief.

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