TY - JOUR
KW - Anatexis
KW - Chinese Altai
KW - Continental stabilization
KW - I-type granitoids
KW - Volcanogenic sediments
AU - Yanqiong Huang
AU - Yingde Jiang
AU - Stephen Collett
AU - Sheng Wang
AU - Kang Xu
AU - Tan Shu
AU - Pengfei Li
AU - Chao Yuan
AB - The mechanism for generation of Silurian-Devonian hornblende-bearing I-type granitoids in the Chinese Altai still remains rather obscure. The possibility that they are derived from the regional anatexis of the Ordovician accretionary wedge, i.e., the Habahe Group, is investigated. The Habahe Group contains a large number of intermediate-to-basic components. These components occur mainly as interlayered volcanogenic bands or admixtures and less commonly as blocks varying in size from several meters to several hundreds of meters. Geochemically, this volcanogenic component is characterized by enrichment of large-ion lithophile elements relative to many of the high-field strength elements and rather radiogenic Nd isotopic signatures (εNd(t): +4.1 to +9.1). Phase equilibrium and trace element modelling indicate that partial melting of the volcanogenic component at an attainable 900–1000 °C can produce 30–35 vol% silicic melts that show a good chemical match, in terms of major element contents and trace element patterns, with those of the local I-type granitoids. Combined with regional available data, we suggest that Silurian-Devonian hornblende-bearing I-type granitoids could be derived from the partial melting of the volcanogenic components of the Habahe Group and previously inferred large input of mantle-derived magma is un-necessary. Regional anatexis of the Ordovician accretionary wedge led to the stabilization of the wedge, which may represent an important mechanism contributing to the formation of vertically stratified continental crust in accretionary orogens in general.
BT - Gondwana Research
DA - 2019/09/10/
DO - 10.1016/j.gr.2019.07.019
N2 - The mechanism for generation of Silurian-Devonian hornblende-bearing I-type granitoids in the Chinese Altai still remains rather obscure. The possibility that they are derived from the regional anatexis of the Ordovician accretionary wedge, i.e., the Habahe Group, is investigated. The Habahe Group contains a large number of intermediate-to-basic components. These components occur mainly as interlayered volcanogenic bands or admixtures and less commonly as blocks varying in size from several meters to several hundreds of meters. Geochemically, this volcanogenic component is characterized by enrichment of large-ion lithophile elements relative to many of the high-field strength elements and rather radiogenic Nd isotopic signatures (εNd(t): +4.1 to +9.1). Phase equilibrium and trace element modelling indicate that partial melting of the volcanogenic component at an attainable 900–1000 °C can produce 30–35 vol% silicic melts that show a good chemical match, in terms of major element contents and trace element patterns, with those of the local I-type granitoids. Combined with regional available data, we suggest that Silurian-Devonian hornblende-bearing I-type granitoids could be derived from the partial melting of the volcanogenic components of the Habahe Group and previously inferred large input of mantle-derived magma is un-necessary. Regional anatexis of the Ordovician accretionary wedge led to the stabilization of the wedge, which may represent an important mechanism contributing to the formation of vertically stratified continental crust in accretionary orogens in general.
PY - 2020
SN - 1342-937X
T2 - Gondwana Research
TI - Magmatic recycling of accretionary wedge: A new perspective on Silurian-Devonian I-type granitoids generation in the Chinese Altai
UR - http://www.sciencedirect.com/science/article/pii/S1342937X19302412
ER -