Julie A Dumoulin, Ph.D.

A composite Mesozoic geological history for the Gondwana margins to the Eastern Tethys Ocean can be assembled from stratigraphic successions on the Australian and Himalayan margins and from drill sites of Ocean Drilling Program Legs 122 and 123. During the Triassic, this region drifted northwards, entering tropical paleolatitudes during the Late Triassic-Early Jurassic, then returned to mid-latitu

The Resurrection Peninsula forms the east side of Resurrection Bay (fig. 3). Relief ranges from 437 m (1,434 ft) at the southern end of the peninsula to more than 1,463 m (4,800 ft) opposite the head of the bay. All rock units composing the informally named Resurrection Peninsula ophiolite of Nelson and others (1987) are visible or accessible by boat."Ophiolite" has been a geologic term since 1827

No abstract available.

Lithofacies changes in coeval upper Paleozoic rocks have been used to unravel the tectonic history of northern Alaska (for example, Mayfield and others, 1983). Conodont biostratigraphy and detailed petrologic studies are now revealing facies differences in lower Paleozoic rocks that can also be used to constrain their tectono-sedimentary framework (Dumoulin and Harris, 1987). A basic element of ba

Carbonate rocks characterized by locally abundant stromatolites and coated grains have been found at several localities in the Baird Mountains and Ambler River quadrangles (fig. 1). These rocks are part of a belt of metasedimentary and metaigneous rocks that constitutes the southwestern flank of the Brooks Range; all are included in the parautochthon (Schwatka sequence) of Mayfield and others (198

The contact between the Upper Cretaceous Valdez Group and the Paleocene and Eocene Orca Group has been inferred to be the boundary between the Chugach and the Prince William tectonostratigraphic terranes. Sandstone petrographic data from the Prince William Sound area show no compositional discontinuity across this contact. These data are best explained by considering the Valdez and Orca Groups to

The Resurrection Peninsula forms the east side of Resurrection Bay (Fig. 1). The city of Seward is located at the head of the bay and can be reached from Anchorage by highway (127 mi;204 km). Relief ranges from 1,434 ft (437 m) at the southern end of the peninsula to more than 4,800 ft (1,463 m) 17 mi (28 km) to the north. All rock units composing the informally named Resurrection Peninsula ophiol

Lower Paleozoic carbonate rocks in the Baird Mountains quadrangle form a relatively thin, chiefly shallow-water succession that has been thrust-faulted and metamorphosed to blueschist and greenschist facies. Although this succession was thought to be mostly Devonian until recently, a large part of it is in fact pre-Silurian in age.Middle and Upper Cambrian rocks - the first confirmed in the wester

No abstract available.

No abstract available.

Extensive seacliff exposures of marble, metadolostone, and schist occur on the north shore of Seward Peninsula in the Kotzebue A-1 and A-2 Quadrangles (fig. 12). Some of the exposed units have no analogs when compared to rocks mapped to the south in the Bendeleben and Solomon Quadrangles. Others are similar to units exposed to the south, but they differ in metamorphic grade and minor, though signi

The Orca Group is a widespread, thick, complexly deformed accretionary sequence of flysch and tholeiitic basalt in the Prince William Sound area (Winkler, 1976; Winkler and Plafker, 1981) (fig. 49). Despite a number of extensive field studies of the Orca Group, reliable data on the age of the unit have been elusive. On the basis of sparse paleontologic and radiometric data, the sequence was regard