HP–UHP Metamorphism and Tectonic Evolution of Orogenic Belts
High pressure (HP) and ultrahigh pressure (UHP) metamorphic rocks play a key role in understanding the tectonic evolution of orogenic belts. They have typically experienced complex changes during subduction and exhumation processes arising from recrystallization, deformation, fluid–rock interactions and even partial melting, and may therefore carry valuable records of evolving geodynamic systems in an orogenic belt. This special publication addresses the current work on HP–UHP metamorphism and its relation to the tectonic evolution of orogenic belts.
This special publication contains fifteen papers covering the important orogenic belts of the Himalaya, Dabie–Sulu, Tian Shan, North Qaidam and others that have been grouped into three parts: (I) new developments in the determination of metamorphic pressure–temperature (PT) conditions and their timing, (II) overview papers of well-known HP–UHP metamorphic belts and (III) research papers for some newly discovered HP–UHP belts.
Thermal structure of the Dabie eclogite-bearing terrane revealed from the results of Ti-in-zircon thermometry
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Published:January 01, 2019
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CiteCitation
Jingbo Liu, Lingmin Zhang, Nanfei Cheng, Yijie Gao, Liewen Xie, 2019. "Thermal structure of the Dabie eclogite-bearing terrane revealed from the results of Ti-in-zircon thermometry", HP–UHP Metamorphism and Tectonic Evolution of Orogenic Belts, Lifei Zhang, Zeming Zhang, Hans-Peter Schertl, Chunjing Wei
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Abstract
Investigation of thermal structure is critical to the interpretation of regional geological structure. This study sampled 12 gneissic outcrops along an approximately 35 km-long profile striking north–south in the Dabie eclogite-bearing terrane. Nanoscale secondary-ion mass spectrometry (Nano-SIMS) was used to analyse the Ti content of zircons from the rocks, and a Ti-in-zircon thermometer was adopted to measure the metamorphic temperatures of formation. Zircons contain three or four different cathodoluminescent (CL) zones, which correspondingly yield significant metamorphic temperature estimates. The metamorphic temperatures decrease along the formation sequence of zircon zones, suggesting that zircon zones formed along an exhumation pressure–temperature (P–T) path. The peak metamorphic temperatures recorded in zircons from gneissic samples range from 500 to 800°C and appear to be comparable with the results from the eclogites enclosed in corresponding gneisses. The determined peak metamorphic temperatures yield large temperature differences from 50 to 200°C between neighbouring petrological units or samples, which occur within distances of 1–4 km. The distinct temperature differences suggest that the Dabie eclogite-bearing terrane consists of a stack of seven or eight tectonometamorphic slices along the profile.
- Asia
- cathodoluminescence
- China
- crystal growth
- crystal structure
- crystal zoning
- Dabie Mountains
- eclogite
- equilibrium
- Far East
- geologic thermometry
- ion probe data
- isotope ratios
- mass spectra
- metals
- metamorphic rocks
- metamorphism
- mineral assemblages
- mineral composition
- morphology
- nesosilicates
- orthosilicates
- P-T conditions
- pressure
- protoliths
- regional
- samples
- silicates
- spectra
- tectonics
- temperature
- terranes
- Th/U
- thermal regime
- titanium
- U/Pb
- zircon
- zircon group