Whitestripe Marble of southeast Alaska

Unit symbol: Trwm
Age range Triassic? (252.2 to 201.3 Ma)
Lithology: Sedimentary
Group name: Marble and limestone of Wrangellia
A long narrow belt of nonfossiliferous, massive to thick-bedded, white to light-gray, fine-grained marble. Composed of nearly pure calcite, but locally contains accessory chlorite, sericite, graphite, quartz, albite, and pyrite (Johnson and Karl, 1985). Plafker and others (1976) and Jones and others (1977) correlate the Whitestripe Marble with the Chitistone Limestone (unit Trcnk) in the Wrangell Mountains and therefore considered it to be a part of the Wrangellia terrane along with the Goon Dip Greenstone (unit Trn). Unit was assigned a Triassic(?) age by Loney and others (1975) on the basis of a fossil found in float. Unit also includes the informally defined marble of Nakwasina Sound (unit Trm of Karl and others, 2015), which consists of light-gray, medium- to thin-bedded metalimestone, which is locally fossiliferous and retains primary bedding structures as well as massive to banded white marble, locally interlayered with volcanic rocks. Unit ranges up to tens of meters in thickness and is associated with volcanic and volcaniclastic rocks mapped in Nakwasina Sound (unit Trvs)

Source map information

Source map Johnson, B.R., and Karl, S.M., 1985, Geologic map of western Chichagof and Yakobi Islands, southeastern Alaska: U.S. Geological Survey Miscellaneous Investigations Series Map I-1506, pamphlet, 15 p., 1 sheet, scale 1:125,000.
Symbol Trw
Unit name Whitestripe Marble
Description A long narrow belt of unfossiliferous, massive to thick bedded, white to light gray, fine grained marble. Composed of nearly pure calcite, but locally contains accessory chlorite, sericite, graphite, quartz, albite, and pyrite. Plafker and others (1976) and Jones and others (1977) correlate the Whitestripe Marble with the Chitistone Limestone in the Wrangell Mountains. The marble is considered to be a part of Wrangellia along with the Goon Dip Greenstone by Jones and others (1977).
Lithology Metamorphic

Correlated geologic units

Label Trw
Description Whitestripe Marble
Geologic age Triassic
Geologic setting Sedimentary, carbonate
Lithology Form Importance
Marble < Metacarbonate < Metasedimentary < Metamorphic Major
Greenstone < Metaigneous < Metamorphic Minor