Metamorphic P-T-t-d evolution of (U)HP metabasites from the South Tianshan accretionary complex (NW China) - Implications for rock deformation during exhumation in a subduction channel

Kód výsledku v IS VaVaI

RIV/67985530:_____/17:00463821 - isvavai.cz

Nalezeny alternativní kódy

RIV/00025798:_____/17:00000008

Výsledek na webu

http://dx.doi.org/10.1016/j.gr.2016.07.007

DOI - Digital Object Identifier

10.1016/j.gr.2016.07.007

Jazyk výsledku

angličtina

Název v původním jazyce

Metamorphic P-T-t-d evolution of (U)HP metabasites from the South Tianshan accretionary complex (NW China) - Implications for rock deformation during exhumation in a subduction channel

Popis výsledku v původním jazyce

The late Carboniferous accretionary system of the South Tianshan orogen (North-Western China) underwent complex structural and polymetamorphic evolution. Combined petrological, geochronological and microstructural analysis of (ultra) high-pressure (UHP) metabasites (eclogites and blueschists) enclosed in metapelites show a relict coarse-grained eclogitic fabric S2 surrounded by a dominant fine-grained eclogite and blueschist facies retrograde fabric S2. The S2 fabric is reworked by upright folds F3 that are responsible for a major shortening of the whole accretionary system. For both the eclogite and blueschist, peak and retrograde P-T conditions have been thermodynamically constrained at 25-26 kbar and 425-500 degrees C and 10-13 kbar and 500-550 degrees C respectively, suggesting a shared exhumation history. The garnet-whole rock-amphibole isochron in the blueschist yielded Lu-Hf and Sm-Nd ages of 326.0+/-2.9 Ma and 318.4+/-3.9 Ma respectively, interpreted to date the prograde to peak metamorphic assemblage. The retrograde path of the eclogite is characterized by heterogeneous omphacite recrystallization into a mylonitic fine-grained matrix and crystallization of blue amphibole. Microstructures in both pristine porphyroclastic and recrystallized fine-grained domains in the eclogite indicate a gradual evolution from constriction-dominated (LNS-type) to flattening-dominated (SNL-type) type of deformation, increase of fabric intensity reflected by gradually growing M-indexes and the development of lattice preferred orientation (LPO) typical for dislocation creep under slightly hydrated conditions. Recrystallization of the matrix in the blueschist is homogeneous, which indicates a matrix dominated channel flow during exhumation. These LPOs evolutions suggest a significant mechanical coupling with the upper plate concomitant with oroclinal bending of the Kazakh orocline.

Název v anglickém jazyce

Metamorphic P-T-t-d evolution of (U)HP metabasites from the South Tianshan accretionary complex (NW China) - Implications for rock deformation during exhumation in a subduction channel

Popis výsledku anglicky

The late Carboniferous accretionary system of the South Tianshan orogen (North-Western China) underwent complex structural and polymetamorphic evolution. Combined petrological, geochronological and microstructural analysis of (ultra) high-pressure (UHP) metabasites (eclogites and blueschists) enclosed in metapelites show a relict coarse-grained eclogitic fabric S2 surrounded by a dominant fine-grained eclogite and blueschist facies retrograde fabric S2. The S2 fabric is reworked by upright folds F3 that are responsible for a major shortening of the whole accretionary system. For both the eclogite and blueschist, peak and retrograde P-T conditions have been thermodynamically constrained at 25-26 kbar and 425-500 degrees C and 10-13 kbar and 500-550 degrees C respectively, suggesting a shared exhumation history. The garnet-whole rock-amphibole isochron in the blueschist yielded Lu-Hf and Sm-Nd ages of 326.0+/-2.9 Ma and 318.4+/-3.9 Ma respectively, interpreted to date the prograde to peak metamorphic assemblage. The retrograde path of the eclogite is characterized by heterogeneous omphacite recrystallization into a mylonitic fine-grained matrix and crystallization of blue amphibole. Microstructures in both pristine porphyroclastic and recrystallized fine-grained domains in the eclogite indicate a gradual evolution from constriction-dominated (LNS-type) to flattening-dominated (SNL-type) type of deformation, increase of fabric intensity reflected by gradually growing M-indexes and the development of lattice preferred orientation (LPO) typical for dislocation creep under slightly hydrated conditions. Recrystallization of the matrix in the blueschist is homogeneous, which indicates a matrix dominated channel flow during exhumation. These LPOs evolutions suggest a significant mechanical coupling with the upper plate concomitant with oroclinal bending of the Kazakh orocline.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10505 - Geology

Projekt

Výsledek vznikl pri realizaci vícero projektů. Více informací v záložce Projekty.

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2017

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Gondwana Research

ISSN

1342-937X

e-ISSN

—

Svazek periodika

47

Číslo periodika v rámci svazku

July

Stát vydavatele periodika

NL - Nizozemsko

Počet stran výsledku

27

Strana od-do

161-187

Kód UT WoS článku

000400971500009

EID výsledku v databázi Scopus

2-s2.0-84994758779