Mineral Resources On-Line Spatial Data
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Geologic units containing 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
- 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.
- 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 Jayko (unpublished data, 1985) in Curry and southern Coos Counties
- 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.