Gabbro, southwest Alaska

Unit symbol: Tgbw
Age range Tertiary, Paleogene? (66 to 56 Ma)
Lithology: Igneous - Plutonic
Group name: Gabbroic rocks in southern Alaska
Unit occurs as small plutons in the McGrath, Lime Hills, Lake Clark, and Tyonek quadrangles. Dark-colored hornblende and pyroxene-hornblende fine- to medium-grained gabbro (McGrath quadrangle: Bundtzen and others, 1997a; Lime Hills quadrangle: Gamble and others, 2013) or hornblende and biotite-bearing olivine gabbronorite (Lake Clark quadrangle: Nelson and others, 1983)

Source map information

Source map Haeussler, P.J., 2007, Unpublished data.
Symbol Tlpg
Unit name Leucogabbro
Description Leucogabbro, probably Paleocene
Lithology Igneous

Correlated geologic units

Label Tgl
Description Hornblende and pyroxene-hornblende gabbro, southwest Alaska
Geologic age Paleocene
Geologic setting Intrusive
Lithology Form Importance
Gabbro < Gabbroic < Plutonic < Igneous Pluton Major
Peridotite < Ultramafic < Plutonic < Igneous Incidental
Pyroxenite < Ultramafic < Plutonic < Igneous Incidental