The Bird Spring Shelf in southeastern California, along with coeval turbidite basins to the west, records a complex history of late Paleozoic sedimentation, sea-level changes, and deformation along the western North American continental margin. We herein establish detailed correlations between deposits of the shelf and the flanking basins, which we then use to reconstruct the depositional history, paleogeography, and deformational history, including Early Permian emplacement of the regionally significant Last Chance allochthon. These correlations are based on fusulinid faunas, which are numerous both on the shelf and in the adjoining basins. Study of 69 fusulinid species representing all major fusulinid-bearing Pennsylvanian and Lower Permian limestone outcrops of the Bird Spring Shelf in southeastern California, including ten new species of the genera Triticites , Leptotriticites , Stewartina , Pseudochusenella , and Cuniculinella , forms the basis for our correlations. We group these species into six fusulinid zones that we correlate with fusulinid-bearing strata in east-central and southern Nevada, Kansas, and West Texas, and we propose some regional correlations not previously suggested. In addition, we utilize recent conodont data from these areas to correlate our Early Permian fusulinid zones with the standard Global Permian Stages, strengthening their chronostratigraphic value. Our detailed correlations between the fusulinid-bearing rocks of the Bird Spring Shelf and deep-water deposits to the northwest reveal relationships between the history of shelf sedimentation and evolution of basins closer to the continental margin. In Virgilian to early Asselian (early Wolfcampian) time (Fusulinid Zones 1 and 2), the Bird Spring Shelf was flanked on the west by the deep-water Keeler Basin in which calcareous turbidites derived from the shelf were deposited. In early Sakmarian (early middle Wolfcampian) time (Fusulinid Zone 3), the Keeler Basin deposits were uplifted and transported eastward on the Last Chance thrust. By middle Sakmarian (middle middle Wolfcampian) time (within Fusulinid Zone 4), emplacement of the Last Chance allochthon was complete, and subsidence caused by thrust loading had resulted in development of a new turbidite basin (Darwin Basin) along the former western part of the Bird Spring Shelf. At the same time, farther east into the craton, paralic facies began prograding westward, so that the youngest fusulinid-bearing limestones on the shelf in this area become progressively younger to the west. Eventually, in Artinskian to Kungurian (late Wolfcampian to Leonardian) time (Fusulinid Zones 5 and 6), deposition of fusulinid-bearing limestone on the shelf was restricted to a marginal belt between the prograding paralic facies to the east and the Darwin Basin to the west. Development of the Keeler Basin in Pennsylvanian to earliest Permian time was approximately coeval with collision between South America-Africa (Gondwana) and North America (Laurentia) on the Ouachita-Marathon orogenic belt. This basin developed inboard of a northwest-trending, sinistral fault zone that truncated the continental margin. Later, in the Early Permian, the Last Chance allochthon, which was part of a northeast-trending belt of deformation that extended into northeastern Nevada, was emplaced. This orogenic belt probably was driven by convergence at the continental margin to the northwest. This work adds significant detail to existing interpretations of the late Paleozoic as a time of major tectonic instability on the continental margin of southeastern California as it changed from a relatively passive margin that had characterized most of the Paleozoic to an active convergent margin that would characterize the Mesozoic.

In Antarctica, late Paleozoic glacigenic strata occur throughout the Transantarctic, Ellsworth, and Pensacola Mountains and in the Shackleton and Heimefront Ranges. The most laterally and stratigraphic continuous exposures occur in the central Transantarctic and Darwin Mountains. These strata were deposited within two topographically expressed basins. The larger of the two basins was a trough-shaped basin that extended between the present locations of the Darwin and Amundsen Glaciers. Basement highs surrounded the basins and formed uplands onto which preglacial, glacial, and postglacial strata onlapped. An examination of late Paleozoic glacigenic units in the Darwin Mountains and the central Transantarctic Mountains reveals that Permian glacio marine sediments were deposited within the basins, and that subglacial diamictites and proximal glaciomarine sediments were deposited along basin margins. This is in marked contrast to earlier reports that identified glacigenic strata in the Transantarctic Mountains as the deposits of a terrestrial glacial system. On some highs, the occurrence of paleosols overlain by postglacial strata suggests that ice-free areas occurred locally along basin margins. A correlation of fossil spores and pollen with Australian palynomorph zones suggests that the Antarctic glacigenic strata are restricted to the Lower Permian. These findings suggest that glaciation was less widespread (temporally and spatially) than previously hypothesized. It is thus unlikely that a single, massive ice sheet covered Antarctica continuously at any time during the Carboniferous and Permian.