Calcareous microfossils from the Upper Triassic of northeastern New Mexico
— Kenneth K. Kietzke


The Chinle and Sloan Canyon formations of northeastern New Mexico have yielded a small fauna of calcareous microfossils including Stellatochara, Altochara, Spirorbis, Darwinula and Limnocytheriinae, genus and species indeterminate. These fossils are the first such fossils reported and illustrated from these formations. The fossils indicate aquatic environments low in turbidity and high in dissolved carbonate. The associated sedimentology suggests the upper shale member of the Chinle Formation was dominated by channelabandoned "oxbow" lakes, while the Redonda Member of the Chinle and the Sloan Canyon Formation were more lacustrine. The association of Darwinula, Spirorbis and various charophytes is typical of late Paleozoic freshwater environments suggesting the freshwater Triassic ecosystem was not significantly disrupted by the terminal Paleozoic extinction event.

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Recommended Citation:

  1. Kietzke, Kenneth K., 1987, Calcareous microfossils from the Upper Triassic of northeastern New Mexico, in: Northeastern New Mexico, Lucas, S. G.; Hunt, A. P., New Mexico Geological Society, Guidebook, 38th Field Conference, pp. 119-126.

[see guidebook]