Geologic units containing blueschist

Mineral Resources On-Line Spatial Data

Blueschist

A schistose metamorphic rock with a blue color owing to the presence of sodic amphibole, glaucophane, or crossite, and commonly mottled bluish-gray lawsonite; characteristic of metamorphism in areas of unusually low thermal gradient, such as subduction zones

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California

Franciscan schist (Early Cretaceous): Blueschist and semi-schist of Franciscan complex
Mesozoic volcanic rocks, unit 1 (Coast Ranges) (Jurassic to Cretaceous): Undivided Mesozoic volcanic and metavolcanic rocks. Andesite and rhyolite flow rocks, greenstone, volcanic breccia and other pyroclastic rocks; in part strongly metamorphosed. Includes volcanic rocks of Franciscan Complex: basaltic pillow lava, diabase, greenstone, and minor pyroclastic rocks
Schist of various types and ages, unit 8 (Condrey Mountain) (Jurassic(?)): Schists of various types; mostly Paleozoic or Mesozoic age; some Precambrian.
Tertiary-Cretaceous Coastal Belt Rocks (Late Cretaceous to Pliocene): Sandstone, shale and minor conglomerate in coastal belt of northwestern California; included by some in Franciscan Complex. Previously considered Cretaceous, but now known to contain early Tertiary microfossils in places.

Oregon

Otter Point Formation of Dott (1971) and related rocks (Upper Jurassic) (Late Jurassic): Highly sheared graywacke, mudstone, siltstone, and shale with lenses and pods of sheared greenstone, limestone, chert, blueschist, and serpentine. Identified as melange by some investigators
Sedimentary rocks of Dothan Formation and related rocks (Lower Cretaceous and Upper Jurassic) (Late Jurassic to Late Cretaceous): Sandstone, conglomerate, graywacke, rhythmically banded chert lenses. Includes western Dothan and Otter Point Formations of M.C. Blake, Jr. and AS. Jayko (unpublished data, 1985) in Curry and southern Coos Counties

Washington

Pre-Upper Jurassic metamorphic rocks of the low-grade zone (Early Cretaceous metamorphism (Jurassic protolith)): Greenschist of central Whatcom and Skagit Counties.
Pre-Upper Jurassic metamorphic rocks of the low-grade zone (Jurassic): Greenschist, phyllite, and slate; includes some limestone, quartzose phyllite, schistose metaconglomerate, breccia, and basic igneous rocks. Includes schist locally.