ALASKA PALEONTOLOGICAL DATABASE – A VERSITAL TOOL FOR GEOLOGISTS IN FIELD MAPPING AND TERRANE ANALYSIS

The Alaska Paleontological Database (www.alaskafossil.com) is a versatile web application containing detailed information on fossils and fossil localities throughout Alaska. The data is derived from thousands of unpublished, internal USGS fossil reports (known as E&R reports), published paleontological and geological reports, as well as unpublished oil and mining company reports. The database establishes coherent relationship and linkages among disparate data, providing an easy to use interface for data search and retrieval. One can search for data via multiple criteria such as location, collector, author of a report/reference, geological age, formation, taxon, etc.

Mapping applications include concurrent compilation of numerous fossil localities for geological mapping in the Craig and Taylor Mountains quadrangles of southern Alaska. Analysis of Alaskan terrane faunas from various intervals ranging in age from Ordovician through Middle Jurassic show that the database is extremely useful in distinguishing or linking various terranes. Examples most notable are shown for the Upper Triassic. Accreted terranes of southern Alaska (Wrangellia, Alexander, Farewell, Chulitna, and Peninsular) as well as cratonic east-central Alaska (its farthest north occurrence on the North American craton) all contain the middle to late Norian hydrozoan Heterastridium. Its distribution suggests warm tropical to subtropical settings for these areas, while the Arctic Alaska terrane of northern Alaska completely lacks this faunal element, as well as other warm water indicators such as scleractinian corals, indicating a relatively high (cool-water) paleolatitude setting for the latter. The distributional patterns of Late Triassic gastropods, indicate that some southern Alaskan terranes, such as Wrangellia and Alexander terranes, were separated by a significant enough distance that some gastropod groups, notably those characterized by direct development, share no common elements, whilst other groups such as certain neritimorph taxa characterized by a long-lived planktotrophic larval stage, are present in both terranes.