Radiolarite
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Radiolarite is a siliceous, comparatively hard, fine-grained, chert-like, and homogeneous sedimentary rock that is composed predominantly of the microscopic remains of radiolarians. This term is also
Outcrop of Franciscan radiolarian chert in San Francisco, California
Radiolarian chert outcrop near Cambria, California. Individual beds range from about 2 to 5 cm thick
Radiolarite (Jurassic) from the Alps.
Whetstone limestone from the Ammergau Alps, Upper Bavaria with round radiolarian remains (thin section). The abrasive effect of the whetstones results from the even distribution of the hard radiolarian skeletons in the soft limestone matrix.
Ophiolite
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An ophiolite is a section of Earth's oceanic crust and the underlying upper mantle that has been uplifted and exposed, and often emplaced onto continental crustal rocks.
Ordovician ophiolite in Gros Morne National Park, Newfoundland
Chromitic serpentinite, Bay of Islands Ophiolite, Lewis Hills, Newfoundland
Chromitite ore with chromite (black) & talc and/or antigorite (whitish). Shetland Ophiolite Complex, ~425-500 Ma. Shetland Islands, North Sea, UK
A simplified structure of an ophiolite suite: axial magma chamber pelagic sediments pillow basalts sheeted basaltic dykes intrusive, layered gabbro dunite/peridotite cumulates