Abstract

Study of a number of Permian-Triassic sections in the Kap Stosch region in the summer of 1967 has provided a number of new observations. First, the Permian-Triassic sections southwest of Kap Stosch are of homogeneous shale, silty shale, and siltstone facies. None of the rock units are highly indurated, but all are markedly “soft.” Solifluction has so badly affected all outcrops that meaningful stratigraphic sections are next to impossible to obtain. The lowest Triassic beds in these regions do contain thin (1-5 cm) hard bands consisting of coquinas of ammonoids (Glyptophiceras and Otoceras) and containing fragments of productids, bryozoans, and other fossils of “Permian” affinities.

Southeast of Kap Stosch (e.g., between Rivers 6 and 14) the lowest Triassic strata encompassing the Glyptophiceras Zone are about 200 m thick. They are predominantly arkosic sandstone and conglomerate. A number of horizons yield fragmentary and whole specimens of productid brachiopods, fragments of crinoid stems, bryozoans and other fossils in coarse sandstone and conglomerate matrix, occurring as much as 100 m above the base of the Triassic sequence.

These strata, containing mixed associations, by their thickness, sedimentary structures, and composition, clearly indicate very rapid rates of deposition. These environmental considerations lead to the conclusion that the “Permian” faunal elements almost certainly did not actually live and form part of the benthos during earliest Triassic time. The underlying Permian formations are of diverse facies among which richly-fossiliferous biohermal banks are present elsewhere. Some of these banks weather easily, yielding nearly perfectly preserved fossils free of matrix. We consider it most probable that some of the Permian faunal elements in the lowest Triassic formations have been brought into that environment as argillaceous boulders, that once coming to rest, dissolved, leaving well-preserved fossils that were rapidly buried in the coarse sediment and in a free state were transported very little. The majority of fossils, however, were washed out of soft rocks and were badly broken during transportation.

We conclude that the Permian-Triassic sequence in the area encompasses a break equivalent to at least the Dzhulfian Stage.