Proterozoic blueschist-bearing mélange in the Anti-Atlas mountains, Morocco

Kevin P. Hefferan; Hassan Admou; Rabia Hilal; Jeffrey A. Karson; Ali Saquaque; Thierry Juteau; M. Marcel Bohn; Scott D. Samson; Jacques M. Kornprobst

doi:10.1016/S0301-9268(02)00109-2

Proterozoic blueschist-bearing mélange in the Anti-Atlas mountains, Morocco

Kevin P. Hefferan, Hassan Admou, Rabia Hilal, Jeffrey A. Karson, Ali Saquaque, Thierry Juteau, M. Marcel Bohn, Scott D. Samson, Jacques M. Kornprobst

Department of Earth & Environmental Sciences

Research output: Contribution to journal › Article › peer-review

62 Scopus citations

Abstract

Blueschists from the Bou Azzer inlier provide compelling evidence for Late Proterozoic subduction in the Anti-Atlas Mountains of Morocco. High-pressure/low-temperature metabasites containing blue amphibole minerals crossite and magnesioriebeckite record pressures in excess of 5 kbar. Together with regional relationships, the geologic setting of the blueschists constrains the polarity of Pan African subduction in this region, which occurred from ∼ 750 to 600 Ma. Blueschist facies rocks crop out in a heterogeneous assemblage of variably deformed and metamorphosed tectonic slices of ophiolitic fragments enclosed in a schistose serpentinite matrix. The mélange belt containing the blueschist facies rocks is intruded by a number of diorite plutons, one of which has yielded a U/Pb radiometric age of 650 Ma. Together with Transaharan Belt to the southeast, the Anti-Atlas suture zone exposed within the Bou Azzer inlier contains among the oldest known blueschist-bearing, ophiolitic mélanges in the world.

Original language	English (US)
Pages (from-to)	179-194
Number of pages	16
Journal	Precambrian Research
Volume	118
Issue number	3-4
DOIs	https://doi.org/10.1016/S0301-9268(02)00109-2
State	Published - Nov 25 2002

Keywords

Anti-Atlas Mountains
Blueschist
Neoproterozoic
Ophiolites
Pan African orogeny

ASJC Scopus subject areas

Geology
Geochemistry and Petrology

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10.1016/S0301-9268(02)00109-2

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title = "Proterozoic blueschist-bearing m{\'e}lange in the Anti-Atlas mountains, Morocco",

abstract = "Blueschists from the Bou Azzer inlier provide compelling evidence for Late Proterozoic subduction in the Anti-Atlas Mountains of Morocco. High-pressure/low-temperature metabasites containing blue amphibole minerals crossite and magnesioriebeckite record pressures in excess of 5 kbar. Together with regional relationships, the geologic setting of the blueschists constrains the polarity of Pan African subduction in this region, which occurred from ∼ 750 to 600 Ma. Blueschist facies rocks crop out in a heterogeneous assemblage of variably deformed and metamorphosed tectonic slices of ophiolitic fragments enclosed in a schistose serpentinite matrix. The m{\'e}lange belt containing the blueschist facies rocks is intruded by a number of diorite plutons, one of which has yielded a U/Pb radiometric age of 650 Ma. Together with Transaharan Belt to the southeast, the Anti-Atlas suture zone exposed within the Bou Azzer inlier contains among the oldest known blueschist-bearing, ophiolitic m{\'e}langes in the world.",

keywords = "Anti-Atlas Mountains, Blueschist, Neoproterozoic, Ophiolites, Pan African orogeny",

author = "Hefferan, {Kevin P.} and Hassan Admou and Rabia Hilal and Karson, {Jeffrey A.} and Ali Saquaque and Thierry Juteau and Bohn, {M. Marcel} and Samson, {Scott D.} and Kornprobst, {Jacques M.}",

note = "Funding Information: National Geographic Society Committee for Research and Exploration Grant (No. 6994-01) and the University of Wisconsin-Stevens Point UPDC Grant generously provided financial support for this project. Thoughtful reviews by R. Caby, K. Attoh and A. Kr{\"o}ner greatly improved this manuscript and are much appreciated. Special thanks to Tami Trinoskey, and to Reminex for providing logistical support in the field. Thierry Juteau and M. Marcel Bohn assisted in the microprobe analyses and their efforts are greatly appreciated. ",

year = "2002",

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doi = "10.1016/S0301-9268(02)00109-2",

language = "English (US)",

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T1 - Proterozoic blueschist-bearing mélange in the Anti-Atlas mountains, Morocco

AU - Hefferan, Kevin P.

AU - Admou, Hassan

AU - Hilal, Rabia

AU - Karson, Jeffrey A.

AU - Saquaque, Ali

AU - Juteau, Thierry

AU - Bohn, M. Marcel

AU - Samson, Scott D.

AU - Kornprobst, Jacques M.

N1 - Funding Information: National Geographic Society Committee for Research and Exploration Grant (No. 6994-01) and the University of Wisconsin-Stevens Point UPDC Grant generously provided financial support for this project. Thoughtful reviews by R. Caby, K. Attoh and A. Kröner greatly improved this manuscript and are much appreciated. Special thanks to Tami Trinoskey, and to Reminex for providing logistical support in the field. Thierry Juteau and M. Marcel Bohn assisted in the microprobe analyses and their efforts are greatly appreciated.

PY - 2002/11/25

Y1 - 2002/11/25

N2 - Blueschists from the Bou Azzer inlier provide compelling evidence for Late Proterozoic subduction in the Anti-Atlas Mountains of Morocco. High-pressure/low-temperature metabasites containing blue amphibole minerals crossite and magnesioriebeckite record pressures in excess of 5 kbar. Together with regional relationships, the geologic setting of the blueschists constrains the polarity of Pan African subduction in this region, which occurred from ∼ 750 to 600 Ma. Blueschist facies rocks crop out in a heterogeneous assemblage of variably deformed and metamorphosed tectonic slices of ophiolitic fragments enclosed in a schistose serpentinite matrix. The mélange belt containing the blueschist facies rocks is intruded by a number of diorite plutons, one of which has yielded a U/Pb radiometric age of 650 Ma. Together with Transaharan Belt to the southeast, the Anti-Atlas suture zone exposed within the Bou Azzer inlier contains among the oldest known blueschist-bearing, ophiolitic mélanges in the world.

AB - Blueschists from the Bou Azzer inlier provide compelling evidence for Late Proterozoic subduction in the Anti-Atlas Mountains of Morocco. High-pressure/low-temperature metabasites containing blue amphibole minerals crossite and magnesioriebeckite record pressures in excess of 5 kbar. Together with regional relationships, the geologic setting of the blueschists constrains the polarity of Pan African subduction in this region, which occurred from ∼ 750 to 600 Ma. Blueschist facies rocks crop out in a heterogeneous assemblage of variably deformed and metamorphosed tectonic slices of ophiolitic fragments enclosed in a schistose serpentinite matrix. The mélange belt containing the blueschist facies rocks is intruded by a number of diorite plutons, one of which has yielded a U/Pb radiometric age of 650 Ma. Together with Transaharan Belt to the southeast, the Anti-Atlas suture zone exposed within the Bou Azzer inlier contains among the oldest known blueschist-bearing, ophiolitic mélanges in the world.

KW - Anti-Atlas Mountains

KW - Blueschist

KW - Neoproterozoic

KW - Ophiolites

KW - Pan African orogeny

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JF - Precambrian Research

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ER -

Proterozoic blueschist-bearing mélange in the Anti-Atlas mountains, Morocco

Abstract

Keywords

ASJC Scopus subject areas

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