Limestone

Unit symbol: Pls
Age range Permian (298.9 to 252.2 Ma)
Lithology: Sedimentary
Group name: Limestone and calcareous clastic rocks
Only known exposure is 40 m of thin- to thick-bedded, medium-grained, crystalline, tan to gray limestone that contains thin interbeds of chert, located on a small islet (100 by 200 m) at entrance to Puale Bay on Alaska Peninsula. Hanson (1957) reported age of late mid-Permian (early Guadalupian) for these rocks on the basis of poorly preserved and silicified coral, brachiopod, and foraminifer fossils. No contacts are exposed, although the highly contorted beds dip about 40° NW., which places them structurally beneath Triassic rocks that are located on other islands about 1 km away

Source map information

Source map Detterman, R.L., Case, J.E., Wilson, F.H., and Yount, M.E., 1987, Geologic map of the Ugashik, Bristol Bay, and western part of Karluk quadrangle, Alaska: U.S. Geological Survey Miscellaneous Investigations Series Map I-1685, 1 sheet, scale 1:250,000.
Symbol Pls
Unit name Limestone
Description Consists of 40 m of massive, light-gray, crystalline limestone containing thin interbeds of chert, located on a small islet (100 by 200 m) at entrance to Puale Bay. No contacts are exposed, although highly contorted beds dip about 40° northwest, which places them structurally beneath Triassic rocks that are located on other islands about 1 km away
Lithology Sedimentary

Correlated geologic units

Label Pls
Description Unnamed Permian limestone
Geologic age Permian
Geologic setting Sedimentary, carbonate
Lithology Form Importance
Limestone < Carbonate < Sedimentary Tuffaceous Major
Chert < Chemical < Sedimentary Bed Incidental