Tianjiao Sang , Fuping Pei , Jiaqi Liu , Zhiwei Wang , Bingqian Ding , Jingyang Wei , Zicheng Guan
{"title":"中亚造山带东部两个不同的早古生代俯冲带：俯冲再循环和弧演化的证据","authors":"Tianjiao Sang , Fuping Pei , Jiaqi Liu , Zhiwei Wang , Bingqian Ding , Jingyang Wei , Zicheng Guan","doi":"10.1016/j.gr.2024.06.021","DOIUrl":null,"url":null,"abstract":"<div><p>This paper presents zircon U–Pb dating and Hf isotopic, and whole-rock geochemical and Sr–Nd isotopic data for early Paleozoic igneous rocks as well as zircon U–Pb dating for the sedimentary rocks of the Songnen Massif within the eastern Central Asian Orogenic Belt (CAOB), aiming to reveal arc magma evolution process. The zircon U–Pb dating results of the siltstone of the Xiaojingou Formation yielded 450 Ma, 471 Ma, 502 Ma, 773 Ma, 818 Ma and 949 Ma age peaks, as well as multi-episodic Paleo-proterozoic ages (2486-1612 Ma), implying its deposition time is younger than ∼ 450 Ma. The zircon U–Pb dating results reveal that the Songnen Massif exists three episodes of volcanic rocks of the middle Cambrian (502 Ma), Middle Ordovician (453-449 Ma) and the Silurian (435-420 Ma). The middle Cambrian basalts are low-K tholeiitic to calc-alkaline series, weakly depleted ε<sub>Hf</sub>(t) and ε<sub>Nd</sub>(t) values. They were derived from the weakly depleted mantle metasomatized by slab fluid in an immature island arc setting. The Middle Ordovician to Silurian volcanic rocks show SiO<sub>2</sub> of 49.4–58.1 wt%, plotting into high-K calc-alkaline series, which are also featured by higher Th/Nd and (Hf/Sm)<sub>PM</sub> ratios, together with moderate depleted ε<sub>Nd</sub>(t) values, suggesting their derivation of the depleted mantle wedge metasomatized by sediment-derived melt. In contrast, coeval early Paleozoic volcanic rocks in the eastern Xing’an Massif with the MORB-like ε<sub>Nd</sub>(t) values are characterized by an origin of the depleted mantle wedge and the distinct interaction of oceanic crust melt and mantle peridotite. Combined with the variation of calculated crust thickness, we suggested that there was a continental arc in the eastern Songnen Massif, which developed from immaturity to maturity during middle Cambrian to Silurian, while the early Paleozoic island arc in the eastern Xing’an Massif is characterized by ocean ridge subduction process.</p></div>","PeriodicalId":12761,"journal":{"name":"Gondwana Research","volume":"134 ","pages":"Pages 326-346"},"PeriodicalIF":7.2000,"publicationDate":"2024-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Two distinct early Paleozoic subduction zones in the eastern Central Asian Orogenic Belt: Evidence of subduction recycling and arc evolution\",\"authors\":\"Tianjiao Sang , Fuping Pei , Jiaqi Liu , Zhiwei Wang , Bingqian Ding , Jingyang Wei , Zicheng Guan\",\"doi\":\"10.1016/j.gr.2024.06.021\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>This paper presents zircon U–Pb dating and Hf isotopic, and whole-rock geochemical and Sr–Nd isotopic data for early Paleozoic igneous rocks as well as zircon U–Pb dating for the sedimentary rocks of the Songnen Massif within the eastern Central Asian Orogenic Belt (CAOB), aiming to reveal arc magma evolution process. The zircon U–Pb dating results of the siltstone of the Xiaojingou Formation yielded 450 Ma, 471 Ma, 502 Ma, 773 Ma, 818 Ma and 949 Ma age peaks, as well as multi-episodic Paleo-proterozoic ages (2486-1612 Ma), implying its deposition time is younger than ∼ 450 Ma. The zircon U–Pb dating results reveal that the Songnen Massif exists three episodes of volcanic rocks of the middle Cambrian (502 Ma), Middle Ordovician (453-449 Ma) and the Silurian (435-420 Ma). The middle Cambrian basalts are low-K tholeiitic to calc-alkaline series, weakly depleted ε<sub>Hf</sub>(t) and ε<sub>Nd</sub>(t) values. They were derived from the weakly depleted mantle metasomatized by slab fluid in an immature island arc setting. The Middle Ordovician to Silurian volcanic rocks show SiO<sub>2</sub> of 49.4–58.1 wt%, plotting into high-K calc-alkaline series, which are also featured by higher Th/Nd and (Hf/Sm)<sub>PM</sub> ratios, together with moderate depleted ε<sub>Nd</sub>(t) values, suggesting their derivation of the depleted mantle wedge metasomatized by sediment-derived melt. In contrast, coeval early Paleozoic volcanic rocks in the eastern Xing’an Massif with the MORB-like ε<sub>Nd</sub>(t) values are characterized by an origin of the depleted mantle wedge and the distinct interaction of oceanic crust melt and mantle peridotite. Combined with the variation of calculated crust thickness, we suggested that there was a continental arc in the eastern Songnen Massif, which developed from immaturity to maturity during middle Cambrian to Silurian, while the early Paleozoic island arc in the eastern Xing’an Massif is characterized by ocean ridge subduction process.</p></div>\",\"PeriodicalId\":12761,\"journal\":{\"name\":\"Gondwana Research\",\"volume\":\"134 \",\"pages\":\"Pages 326-346\"},\"PeriodicalIF\":7.2000,\"publicationDate\":\"2024-07-26\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Gondwana Research\",\"FirstCategoryId\":\"89\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S1342937X24002065\",\"RegionNum\":1,\"RegionCategory\":\"地球科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"GEOSCIENCES, MULTIDISCIPLINARY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Gondwana Research","FirstCategoryId":"89","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S1342937X24002065","RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"GEOSCIENCES, MULTIDISCIPLINARY","Score":null,"Total":0}
Two distinct early Paleozoic subduction zones in the eastern Central Asian Orogenic Belt: Evidence of subduction recycling and arc evolution
This paper presents zircon U–Pb dating and Hf isotopic, and whole-rock geochemical and Sr–Nd isotopic data for early Paleozoic igneous rocks as well as zircon U–Pb dating for the sedimentary rocks of the Songnen Massif within the eastern Central Asian Orogenic Belt (CAOB), aiming to reveal arc magma evolution process. The zircon U–Pb dating results of the siltstone of the Xiaojingou Formation yielded 450 Ma, 471 Ma, 502 Ma, 773 Ma, 818 Ma and 949 Ma age peaks, as well as multi-episodic Paleo-proterozoic ages (2486-1612 Ma), implying its deposition time is younger than ∼ 450 Ma. The zircon U–Pb dating results reveal that the Songnen Massif exists three episodes of volcanic rocks of the middle Cambrian (502 Ma), Middle Ordovician (453-449 Ma) and the Silurian (435-420 Ma). The middle Cambrian basalts are low-K tholeiitic to calc-alkaline series, weakly depleted εHf(t) and εNd(t) values. They were derived from the weakly depleted mantle metasomatized by slab fluid in an immature island arc setting. The Middle Ordovician to Silurian volcanic rocks show SiO2 of 49.4–58.1 wt%, plotting into high-K calc-alkaline series, which are also featured by higher Th/Nd and (Hf/Sm)PM ratios, together with moderate depleted εNd(t) values, suggesting their derivation of the depleted mantle wedge metasomatized by sediment-derived melt. In contrast, coeval early Paleozoic volcanic rocks in the eastern Xing’an Massif with the MORB-like εNd(t) values are characterized by an origin of the depleted mantle wedge and the distinct interaction of oceanic crust melt and mantle peridotite. Combined with the variation of calculated crust thickness, we suggested that there was a continental arc in the eastern Songnen Massif, which developed from immaturity to maturity during middle Cambrian to Silurian, while the early Paleozoic island arc in the eastern Xing’an Massif is characterized by ocean ridge subduction process.
期刊介绍：
Gondwana Research (GR) is an International Journal aimed to promote high quality research publications on all topics related to solid Earth, particularly with reference to the origin and evolution of continents, continental assemblies and their resources. GR is an "all earth science" journal with no restrictions on geological time, terrane or theme and covers a wide spectrum of topics in geosciences such as geology, geomorphology, palaeontology, structure, petrology, geochemistry, stable isotopes, geochronology, economic geology, exploration geology, engineering geology, geophysics, and environmental geology among other themes, and provides an appropriate forum to integrate studies from different disciplines and different terrains. In addition to regular articles and thematic issues, the journal invites high profile state-of-the-art reviews on thrust area topics for its column, ''GR FOCUS''. Focus articles include short biographies and photographs of the authors. Short articles (within ten printed pages) for rapid publication reporting important discoveries or innovative models of global interest will be considered under the category ''GR LETTERS''.
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号
