Palynostratigraphy of the subsurface eagle mills formation (Triassic) from a well in east‐central texas, U.S.A.

Abstract

Abstract Well cuttings from the 8300–9500 ft (= 2530–2896 m) levels of the Hinton No. 1 Snider well in Falls County, east‐central Texas, were studied palynologically. The cuttings were prevailingly gray to reddish‐brown shales, and most samples were productive of palynomorphs. The undoubted indigenous palynoflora of the rock indicates late Carnian (Late Triassic) age for the Eagle Mills Formation, representing sedimentation in a Newark‐Basins‐style rift basin. The flora of most of the sampled interval was dominated by monosaccate and bisaccate conifer pollen and spores supporting late Carnian age. These forms also indicate relatively dry climatic conditions. Above 8650 ft the palynoflora is dominated by Corollina (al. Classopollis) pollen, and spores, indicating terminal Triassic to Early Jurassic age. However, the upper levels contain abundant dinoflagellates and spores and pollen of Jurassic to Late Cretaceous age, which clearly came from up‐well caving. It is therefore probable that the post‐Carnian in...