Ohio Range Research Articles

Trace Fossils from the Permian Polarstar Formation Sentinel Mountains, Antarctica

During austral summer 1966-67, the writer spent several weeks engaged in geological exploration and collection of samples, in the Sentinel Mountain region of Antarctica. The original plan had been to search for ribbed fossil conchostracans (leaiids) in the Glossopteris beds of the Polarstar formation (Craddock et al., 1965). It was thought that, if present, such leaiids would permit correlation with the leaiid zone in the Ohio Range (Doumani and Tasch, 1965; Tasch, 1968). Preliminary and limited sampling, however, did not yield any leaiid or other conchostracan fossils. Bulk sampling that alone could prove conclusive, was found to be impossible without heliocopter support, due to terrain difficulties. Despite this, collections were made in other parts of the Polarstar Formation and at other exposures along the slopes of Polarstar Peak. At least one trace fossil (Cochlichnus) from these collections may have affinities with the species of the same genus found in the Ohio Range (Tasch, 1968). If so, the suspected correlation between the Sentinel Mountain and Ohio Range Permian beds would have this additional piece of evidence in its favor. Since Permian fossils (exclusive of the Glossopteris flora) from the Antarctic, are sparse, and Paleozoic trace fossils from Antarctica, though mentioned, (McElroy et al., 1967; Craddock, see next section; Webb, 1963; Allen, 1962) are rarely described, the present paper is written in an effort to begin to fill this gap. It is also the intention to indicate the potential value of Paleozoic trace fossils for regional correlation in the Antarctic.

A Permian Trace Fossil from the Antarctic Ohio Range

A floodplain siltstone of the Permian Mt. Glossopteris Formation (Mercer Ridge, Ohio Range, Antarctica) contained a new vermiform trace fossil (trail). Cochlichnus antarcticus n. sp. is described and figured. This find establishes a second trace fossil zone that is higher in the formation than the basal invertebrate spoor fossils (trails, burrows) reported by Long.

Movement Directions in Late Paleozoic Glacial Rocks of the Horlick and Pensacola Mountains, Antarctica

Striae and associated structures beneath and within the Buckeye Tillite in the Ohio Range of the Horlick Mountains show that Permian(?) glaciers moved toward the west-southwest. Striae in the Wisconsin Range of the Horlicks display similar orientation, but the sense of movement could not be determined. Paleoglaciers in the Neptune Range and the Cordiner Peaks of the Pensacola Mountains moved toward the south-southwest with some dispersion. Paleocurrents flowed parallel to ice motion in the Ohio Range and in the Pensacolas, but they also flowed toward the north-northeast in the Pensacolas.

Leaiid Conchostracan Zone in Antarctica and Its Gondwana Equivalents

Two species of conchostracans (class Crustacea) occur in the coal measures of the Ohio Range, associated with a typical Glossopteris flora. New Leaia and Cyzicus (Lioestheria) species occur in a restricted zone near the top of the stratigraphic section. The biofacies represents a swampy environment and deposition in short-lived ponds of still water under variable weather cycles. The zone compares closely with the leaiid zones in South Africa, South America, and Australia, and is assigned to the Middle-Upper Permian, specifically, Lower Beaufort age.

A GLOSSOPTERIS FLORA FROM THE OHIO RANGE, ANTARCTICA

Cridland, Arthur A. (Ohio State U., Columbus.) A Glossopteris flora from the Ohio Range, Antarctica. Amer. Jour. Bot. 50(2): 186–195. Illus. 1963.—Leaves of Glossopteris indica are the commonest fossils in the Mount Glossopteris Formation on Mount Schopf. Other fossils present are: Glossopteris ampla, G. anguslifolia, G. damudica, G. browniana, detached scales, sporangia of Arberiella containing bisaccate pollen grains, seeds of Samaropsis (principally S. longii), and some obscure fossils. These remains, and associated animal fossils, suggest that the Mount Glossopteris Formation is Permian. The plants evidently grew in a seasonal but favorable climate. These growth conditions indirectly support paleomagnetic calculations which indicate that in Late Permian time, Mount Schopf lay near latitude 50°S.