Ultra-high pressure metamorphism in western Tianshan, China: Part II. Evidence from magnesite in eclogite

  title={Ultra-high pressure metamorphism in western Tianshan, China: Part II. Evidence from magnesite in eclogite},
  author={Lifei Zhang and David J. Ellis and Samantha Williams and Wenbo Jiang},
  journal={American Mineralogist},
  pages={861 - 866}
Abstract Carbonates of ultrahigh-pressure metamorphic (UHPM) origin were discovered in eclogites from western Tianshan, China. In the eclogites, relict magnesite (XMg = 0.79) occurs as rounded to subidiomorphic inclusions (0.01-0.1 mm) within matrix dolomite, and also as rounded inclusions with thin reaction rims of dolomite in glaucophane. Based on the textural evidence and calculated phase relationship, these eclogites record an early UHPM assemblage overprinted by a blueschist assemblage… 

Figures and Tables from this paper

Ultrahigh-pressure metamorphism in eclogites from the western Tianshan high-pressure belt (Xinjiang, western China)-Comment
Despite the absence of ultrahigh-pressure (UHP) minerals such as coesite and microdiamond, Zhang et al. (2002a, 2002b) claimed to have found unambiguous evidence for UHP metamorphism in eclogites
Compositional zoning in dolomite from lawsonite-bearing eclogite (SW Tianshan, China): Evidence for prograde metamorphism during subduction of oceanic crust
Abstract Dolomite with compositional zoning was discovered in carbonate-lawsonite-bearing eclogites in the Tianshan (ultra-)high-pressure/low-temperature metamorphic belt, northwestern China. The
The early exhumation history of the Western Tianshan UHP metamorphic belt, China: New constraints from titanite U–Pb geochronology and thermobarometry
The Chinese Western Tianshan terrane is a well‐known ultrahigh‐pressure (UHP) metamorphic belt that mainly consists of subducted oceanic crustal materials. While two uplift stages have been
Metamorphism of High/ultrahigh-pressure Pelitic–Felsic Schist in the South Tianshan Orogen, NW China: Phase Equilibria and P–T Path
The South Tianshan high/ultrahigh-pressure (HP^UHP) metamorphic belt, NW China is characterized by extensive pelitic^felsic schists with numerous blocks of eclogite, ultramafic rock and marble.The
Coesite inclusions in garnet from eclogitic rocks in western Tianshan, northwest China: Convincing proof of UHP metamorphism
Abstract Coesite inclusions in garnet have been recognized in eclogitic rocks from western Tianshan, northwest China. The coesite grains exhibit distinct radial cracks in host porphyroblastic garnet;
‘Forbidden zone’ subduction of sediments to 150 km depth— the reaction of dolomite to magnesite + aragonite in the UHPM metapelites from western Tianshan, China
The solid‐state reaction magnesite (MgCO3) + calcite (aragonite) (CaCO3) = dolomite (CaMg(CO3)2) has been identified in metapelites from western Tianshan, China. Petrological studies show that two
Ultrahigh pressure metamorphism and tectonic evolution of southwestern Tianshan orogenic belt, China: a comprehensive review
Abstract Recently, a huge ultrahigh-pressure (UHP) metamorphic belt of oceanic type has been recognized in SW Tianshan, China. Petrological studies show that the UHP metamorphic rocks of SW Tianshan
Jadeite- and dolomite-bearing coesite eclogite from western Tianshan, NW China
Jadeite associated with omphacite has been reported from high-pressure, low-temperature (H P -L T ) rocks worldwide. However, the upper pressure stability of this association is not clear in nature.


Ultrahigh-pressure metamorphism in western Tianshan, China: Part I. Evidence from inclusions of coesite pseudomorphs in garnet and from quartz exsolution lamellae in omphacite in eclogites
Abstract Inclusions of coesite pseudomorphs in garnets have been found in type I eclogites interlayered with mafic blueschists and carbonate eclogites, and quartz exsolution lamellae in omphacites
Ultrahigh-Pressure (60 Kbar) Magnesite-Bearing Garnet Peridotites from Northeastern Jiangsu, China
The very high P/T metamorphic belt in China's Shandong and fiangsu provinces, which has drawn much attention because of its numerous coesite-bearing eclogites, also contains little-studied massifs of
The compositional variation of synthetic sodic amphiboles at high and ultra-high pressures
Abstract Sodic amphiboles in high pressure and ultra-high pressure (UHP) metamorphic rocks are complex solid solutions in the system Na2O–MgO–Al2O3–SiO2–H2O (NMASH) whose compositions vary with
Evidence for carbonate in the mantle
The presence of primary carbonate in kimberlite magmas, which erupt tp the Earth's surface from depths of \[gsims]150 km, carrying with them the rare elemental form of carbon, diamond, is evidence
Petrogenesis of impure dolomitic marble from the Dabie Mountains, central China
Petrogeneses of impure dolomitic marble and enclosed eclogite from the Xinyan area, Dabie ultrahigh‐pressure (UHP) metamorphic terrane, central China were investigated with a special focus on fluid