Melange
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In geologic contexts mélange is a large scale breccia formed in the accretionary wedge above a subduction zone. The mélange typically consists of a jumble of large blocks of varied lithologies of altered oceanic crustal material and blocks of continental slope sediments in a sheared mudstone matrix. Mélange occurrences are associated with thrust faulted terranes in orogenic belts. The ultramafic ophiolite sequences which have been obducted onto continental crust are typically underlain by a mélange. Examples include the Franciscan Formation of California and the Bay of Islands ophiolite complex in Newfoundland.
The term mélange is French for mixture.
References
- Blatt, Harvey and Robert Tracy (1996), Petrology, 2nd ed., Freeman (pp. 178, 514), ISBN 0-7167-2438-3.
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