Pleistocene Marine Microfauna in the Bootlegger Cove Clay, Anchorage, Alaska

Abstract

Ostracods and Foraminifera, associated with molluscs, indicate a marine depositional environment for part of the Bootlegger Cove Clay. The definite Arctic and North Atlantic affinities of the microfauna suggest a possible migration through the Bering-Chukchi seaway during the late Pleistocene.

Catalog and initial analyses of geologic data related to Middle to Late Quaternary deposits, Cook Inlet region, Alaska

“…We speculate that conditions in upper Cook Inlet then were similar to present conditions in some of the fjords along the coast of southcentral and southeastern Alaska, except that the waters were more tide dominated. Schmidt (1963) first reported marine foraminifera and ostracods from the shell-rich zone on the south side of Knik Arm near locality ANC-43 (sheet 1). Freshwater microfossils are reported from several BCF zones in the Anchorage area (Schmoll and Yehle, 1986 …”

Geologic map of the Cook Inlet region, Alaska, including parts of the Talkeetna, Talkeetna Mountains, Tyonek, Anchorage, Lake Clark, Kenai, Seward, Iliamna, Seldovia, Mount Katmai, and Afognak 1:250,000-scale quadrangles

“…Miller and Dobrovolny (1959) defined the unit as the Bootlegger Cove Clay and considered the deposit of glaciolacustrine origin, as did Karlstrom (1964) except for one shell-bearing marine horizon. Established as glacioestuarine in origin throughout the exposed formation by Schmidt (1963). Radiocarbon ages of 14,000 to 16,500 years B.P.…”

Cyclic triaxial tests of the Bootlegger Cove Formation, Anchorage, Alaska

“…The Bootlegger Cove Formation is a stratified sequence of clastic sediments that range from clay to boulders which, on the basis of paleontologic evidence (Schmidt, 1963), were deposited in brackish or marine waters. The formation is known to occur at shallow depths beneath most of the western half of metropolitan Anchorage, as well as northward in the Knik Arm area and westward to the Susitna River.…”