OH in zoned amphiboles of eclogite from the western Tianshan, NW-China

Su, Wen; Zhang, Ming; Redfern, Simon A. T.; Gao, Jun; Klemd, Reiner

doi:10.1007/s00531-008-0379-z

Cited by 16 publications

(3 citation statements)

References 42 publications

(53 reference statements)

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“…Miller, 1974;Smulikowski & Smulikowski, 1985;Messiga et al, 1991) but were also more recently addressed (e.g. Su et al, 2009;Tagiri et al, 2010;Wilke et al, 2010a). These studies include the aforementioned eclogites from the Saualpe type locality (Miller, 1990).…”

Section: Introductionmentioning

confidence: 99%

Formation of Amphibole and Clinozoisite-Epidote in Eclogite owing to Fluid Infiltration during Exhumation in a Subduction Channel

Massonne¹

2012

Journal of Petrology

129

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Two eclogites, one from the southern Dabie Shan, China, and the other from the western Erzgebirge, Germany, were studied because of amphibole and clinozoisite^epidote formation either as typical porphyroblasts or as oriented fine-grained matrix minerals. A nearly isobaric prograde path was derived for the eclogite from the Erzgebirge, mainly on the basis of garnet zonation and the reconstruction of P^T pseudosections in the system SiO 2 ^TiO 2 Âl 2 O 3 ^MgO^MnO^FeO^CaO^Na 2 O^K 2 O^H 2 O^O 2 . Peak P^T conditions were 2•8 GPa and 6708C. The retrograde path shows significant cooling during pressure release. In contrast, the Dabie Shan eclogite contains sparse Mg-rich garnet cores pointing to a granulite stage. Subsequently, peak-pressure conditions of 3•5^4•0 GPa were reached at 6208C, followed by a retrograde path that was initially nearly isothermal and then similar to that of the Erzgebirge eclogite. Most of the amphibole and clinozoisiteê pidote grew during early retrogression in the pressure interval 1•8^2•3 GPa (Erzgebirge) or 2•4^2•7 GPa (Dabie Shan) owing to infiltration of hydrous fluids amounting to $1wt % and 0•5 wt % H 2 O, respectively. As a result of this hydration omphacite was partially decomposed, but the remaining omphacite demonstrates that infiltration of H 2 O essentially ceased at 1•8 GPa (Erzgebirge) or 2•4 GPa (Dabie Shan). The fluid infiltration and hence the growth of amphibole and clinozoisite^epidote is proposed to have occurred in a deep-seated subduction channel during ascent of eclogitic material. Subsequently, the eclogites were captured between colliding continental plates and further exhumed in an exhumation channel.

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Section: Introductionmentioning

confidence: 99%

Formation of Amphibole and Clinozoisite-Epidote in Eclogite owing to Fluid Infiltration during Exhumation in a Subduction Channel

Massonne¹

2012

Journal of Petrology

129

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“…Deciphering the deformation and metamorphic history of these high-pressure (HP) and ultra-HP (UHP) metamorphic rocks is essential for reconstructing the tectonic evolution of the Tianshan Belt as well as that of the CAOB. A considerable number of mineralogical, petrological, and geochemical data on these HP/ UHP metamorphic rocks have been documented (Gao et al 1995(Gao et al , 1999Tagiri et al 1995;Klemd 2003;Wei et al 2003;Zhang et al 2003 and references therein;Lin and Enami 2006;Li et al 2007;Lü et al 2008;Simonov et al 2008;Su et al 2009). However, their structural characteristics are insufficiently studied (Gao et al 1995;Lin et al 2009).…”

Section: Introductionmentioning

confidence: 99%

Structural and Geochronological Study of High‐Pressure Metamorphic Rocks in the Kekesu Section (Northwestern China): Implications for the Late Paleozoic Tectonics of the Southern Tianshan

Wang

Faure

Shu³

et al. 2010

The Journal of Geology

165

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Blueschist-and eclogite-facies high-to ultrahigh-pressure (HP/UHP) metamorphic rocks occur in the southern Tianshan Belt. Their deformation and metamorphic history is important for understanding the Paleozoic tectonics of the Central Asian Orogenic Belt. Our study focuses on the structural analysis and geochronology of the HP metamorphic rocks and the surrounding rocks in the Kekesu Section in the southern Chinese Tianshan. Geometric and kinematic analyses indicate three ductile deformation events: a top-to-the-north thrusting, a top-to-the-south shearing, and a dextral wrenching. New 40 Ar/ 39 Ar laser probe plateau ages were obtained on white mica from retrograde blueschist ( and Ma; 1j) and greenschist-facies metasediments ( Ma; 1j). These ages are interpreted as 316 ‫ע‬ 2 ‫ע133‬ 1 3 2 3 ‫ע‬ 1 the time of retrograde recrystallization during exhumation of the HP metamorphic rocks. New structural and isotopic data, in conjunction with previous results, suggest that (1) the collision event occurred during the latest Devonian to earliest Carboniferous, resulting in HP/UHP metamorphism and the top-to-the-north thrusting; (2) the postcollisional exhumation of the HP/UHP metamorphic rocks and extensive retrograde metamorphism under greenschistfacies conditions took place in the Mid-Late Carboniferous and are correlated with south-dipping normal faulting; and (3) Permian ductile dextral shearing and associated granitic intrusion and fluid activity severely overprinted the earlier fabrics.

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“…A common mineralogical feature of exhumed (ultra)high pressure ((U)HP) metabasic eclogite is the occurrence of epidote and/or clinozoisite poikiloblasts associated with compositionally zoned amphibole, the latter typically containing a substantial sodic component (Smulikowski & Smulikowski, ; Messiga et al ., ; Zack et al ., ; Garciá‐Casco et al ., ; Massonne & Kopp, ; Su et al ., ; Wilke et al ., ). These are present in many subduction‐related (U)HP terranes that form during continental collision, although the petrographic significance of this mineralogical pairing is debated (Massonne, ).…”

Section: Introductionmentioning

confidence: 99%

Phase equilibria modelling of retrograde amphibole and clinozoisite in mafic eclogite from the Tso Morari massif, northwest India: constraining the P–T–M(H₂O) conditions of exhumation

Palin

St-Onge

Waters

et al. 2014

Journal Metamorphic Geology

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Phase equilibria modelling of post‐peak metamorphic mineral assemblages in (ultra)high‐P mafic eclogite from the Tso Morari massif, Ladakh Himalaya, northwest India, has provided new insights into the potential behaviour and source of metamorphic fluid during exhumation, and constrained the P–T conditions of hydration. A series of P–M(H2O) pseudosections constructed in the Na2O–CaO–K2O–FeO–MgO–Al2O3–SiO2–H2O–TiO2–O (NCKFMASHTO) system show that a number of petrographically distinct hydration episodes occurred during exhumation from peak P–T conditions (~640 °C, 27–28 kbar), resulting in the formation of abundant compositionally zoned amphibole and minor clinozoisite poikiloblasts at the expense of a peak assemblage dominated by garnet and omphacite. Initial hydration is interpreted to have occurred as a result of the destabilization of talc following isothermal decompression to ~23 kbar, which led to the formation of barroisite–winchite amphibole core domains. An episode of fluid infiltration from an external source at ~19 kbar, with or without syn‐decompressional cooling to ~560 °C, resulted in further barroisitic–winchitic amphibole growth, followed by the formation of clinozoisite poikiloblasts. Continued buoyancy‐driven exhumation to the base of the lower crust is constrained to have taken place with no additional fluid input. A final hydration event is characterized by the formation of magnesiohornblende rims on the barroisite–winchite cores, with the former interpreted to have formed during later prograde overprinting in the middle crust associated with the final stages of exhumation. Notably, the vast majority of externally sourced H2O, comprising just over half of the current bulk rock fluid content, was added during this later hydration event. In a middle crustal setting, this is interpreted as the result of devolatilization reactions occurring in migmatitic host orthogneiss and/or metasedimentary units, or following the crystallization of partial melt.

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OH in zoned amphiboles of eclogite from the western Tianshan, NW-China

Cited by 16 publications

References 42 publications

Formation of Amphibole and Clinozoisite-Epidote in Eclogite owing to Fluid Infiltration during Exhumation in a Subduction Channel

Formation of Amphibole and Clinozoisite-Epidote in Eclogite owing to Fluid Infiltration during Exhumation in a Subduction Channel

Structural and Geochronological Study of High‐Pressure Metamorphic Rocks in the Kekesu Section (Northwestern China): Implications for the Late Paleozoic Tectonics of the Southern Tianshan

Phase equilibria modelling of retrograde amphibole and clinozoisite in mafic eclogite from the Tso Morari massif, northwest India: constraining the P–T–M(H₂O) conditions of exhumation

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OH in zoned amphiboles of eclogite from the western Tianshan, NW-China

Cited by 16 publications

References 42 publications

Formation of Amphibole and Clinozoisite-Epidote in Eclogite owing to Fluid Infiltration during Exhumation in a Subduction Channel

Formation of Amphibole and Clinozoisite-Epidote in Eclogite owing to Fluid Infiltration during Exhumation in a Subduction Channel

Structural and Geochronological Study of High‐Pressure Metamorphic Rocks in the Kekesu Section (Northwestern China): Implications for the Late Paleozoic Tectonics of the Southern Tianshan

Phase equilibria modelling of retrograde amphibole and clinozoisite in mafic eclogite from the Tso Morari massif, northwest India: constraining the P–T–M(H2O) conditions of exhumation

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Phase equilibria modelling of retrograde amphibole and clinozoisite in mafic eclogite from the Tso Morari massif, northwest India: constraining the P–T–M(H₂O) conditions of exhumation