Paleocene Sandstones Research Articles

Origin and Classification of Cretaceous, Paleocene, and Eocene Sandstones of Western Venezuela

In western Venezuela the tectonics, facies, and paleogeography of the Cretaceous, Paleocene, and Eocene are relatively well known. A study of the sandstones of these series affords a good case history to test some of the modern concepts in sandstone petrography such as tectonic control of sandstone properties and textural and mineralogical maturity. In this case sandstone mineralogy and mineralogical maturity are functions of source area petrography, weathering, and erosion. Textural maturity on the other hand is related to environments in the depositional basin. No fixed relation between tectofacies and depositional environments seems to be present. Consequently sandstone properties do not appear to depend to any great extent on the tectofacies in the basin. The observat ons suggest caution in applying to the field of sandstone genetics and sandstone classification general concepts as for example the idea of tectonic control of sandstone petrography.

Mineralogy of Late Upper Cretaceous, Paleocene, and Eocene Sandstones of Los Banos District, West Border of San Joaquin Valley, California

The mineral composition of 192 outcrop and core samples from sandstones of late Upper Cretaceous, Paleocene, and Eocene age in the Los Banos district are tabulated. The mineral composition appears to afford few data for differentiating and correlating late Upper Cretaceous and Paleocene sandstones of the Los Banos district. The Eocene Domengine formation in the southern part of the area shows a marked increase in glaucophane as compared with the Paleocene and late Upper Cretaceous sandstones. The mineral suites are interpreted as indicating derivation from eastern and western sources, glaucophane being the most reliable indicator of a western source. Kaolinite, possibly of the anauxite type, occurs in white sands of Ione type in the Martinez (?) formation of possible Pale cene age, in outcrop sections and in a subsurface sand.