TY - JOUR
T1 - Structure and petrology of the Altan Uul ophiolite: new evidence for a Late Carboniferous suture in the Gobi Altai, southern Mongolia
AU - Rippington, Stephen
AU - Cunningham, Dickson
AU - England, Richard
PY - 2008
Y1 - 2008
N2 - Altan Uul and Nemegt Uul are mountain ranges in southern Mongolia contg. polydeformed Mid- to Late Palaeozoic sedimentary, volcanic and metamorphic rocks uplifted at a restraining bend along the Gobi-Tien Shan left-lateral strike-slip fault system. Altan and Nemegt Uul contain part of an intra-oceanic island arc that was active during the Carboniferous. Thrust-bound sequences of highly fractured pillow basalt, cumulate gabbro, peridotite, serpentinite and jasperoid occur directly north of the arc rocks in at least three discrete belts and are interpreted to be fragments of an ophiolite. Metamorphosed marine sediments that have undergone intense contractional strain lie north of, and structurally below, the ophiolitic rocks. The gabbros within the ophiolitic sequences have undergone prograde metamorphic reactions consistent with an ocean-floor environment, and trace element analyses are similar to those from cumulate gabbros of the Oman ophiolite. Combined field and petrol. evidence suggests that there is an east-west-trending south-dipping Late Carboniferous suture in Altan and Nemegt Uul that may be regionally correlated in the southern Gobi Altai region. This proposed suture represents a new and important tectonic boundary between tectonostratigraphic terranes in southern Mongolia, requiring modification of existing models of Late Palaeozoic terrane accretion in the Central Asian Orogenic Belt. [on SciFinder (R)]
AB - Altan Uul and Nemegt Uul are mountain ranges in southern Mongolia contg. polydeformed Mid- to Late Palaeozoic sedimentary, volcanic and metamorphic rocks uplifted at a restraining bend along the Gobi-Tien Shan left-lateral strike-slip fault system. Altan and Nemegt Uul contain part of an intra-oceanic island arc that was active during the Carboniferous. Thrust-bound sequences of highly fractured pillow basalt, cumulate gabbro, peridotite, serpentinite and jasperoid occur directly north of the arc rocks in at least three discrete belts and are interpreted to be fragments of an ophiolite. Metamorphosed marine sediments that have undergone intense contractional strain lie north of, and structurally below, the ophiolitic rocks. The gabbros within the ophiolitic sequences have undergone prograde metamorphic reactions consistent with an ocean-floor environment, and trace element analyses are similar to those from cumulate gabbros of the Oman ophiolite. Combined field and petrol. evidence suggests that there is an east-west-trending south-dipping Late Carboniferous suture in Altan and Nemegt Uul that may be regionally correlated in the southern Gobi Altai region. This proposed suture represents a new and important tectonic boundary between tectonostratigraphic terranes in southern Mongolia, requiring modification of existing models of Late Palaeozoic terrane accretion in the Central Asian Orogenic Belt. [on SciFinder (R)]
UR - http://www.scopus.com/inward/record.url?scp=44349150517&partnerID=8YFLogxK
UR - http://dx.doi.org/10.1144/0016-76492007-091
U2 - 10.1144/0016-76492007-091
DO - 10.1144/0016-76492007-091
M3 - Article
SN - 0016-7649
VL - 165
SP - 711
EP - 723
JO - Journal of the Geological Society
JF - Journal of the Geological Society
IS - 3
ER -