Multichronometric evidence for an in situ origin of the ultrahigh pressure metamorphic terrane of Dabieshan, China
Journal
Journal of Geology
Journal Volume
109
Journal Issue
5
Pages
633-646
Date Issued
2001
Author(s)
Abstract
U‐Pb zircon data on gneisses indicate a Late Proterozoic protolith at ∼700 Ma at Bixiling and a Late Archean to Early Proterozoic for the Shuanghe sheet within the ultrahigh‐pressure metamorphic terrane of Dabieshan (China). U‐Pb zircon and Sm‐Nd dates on the gneisses of the Shuanghe sheet constrain a metamorphic peak at ∼230 Ma. Rb‐Sr and 40Ar‐39Ar analyses of phengite from five gneisses in the Bixiling Complex yield ages at 198–212 Ma, overlapping the 190–220‐Ma age on eclogites. The host gneisses record a similar metamorphic evolution as the coesite‐bearing eclogites since both the peak and the retrograde evolution were contemporaneous. This argues for an in situ tectonic relationship.
SDGs
Type
journal article