DOI: 10.1016/j.earscirev.2021.103648
论文题名: Sub-parallel ridge-trench interaction and an alternative model for the Silurian-Devonian archipelago in Western Junggar and North-Central Tianshan in NW China
作者: Zhang J. ; Chen Y. ; Xiao W. ; Wakabayashi J. ; Windley B.F. ; Yin J.
刊名: Earth Science Reviews
ISSN: 00128252
出版年: 2021
卷: 217 语种: 英语
中文关键词: CAOB
; Double magmatic belts
; Orogenic architecture
; Ridge subduction
; Tianshan
; Western Junggar
英文关键词: archipelago
; Devonian
; magma
; orogenic belt
; orogeny
; plate boundary
; Silurian
; subduction
; trench
; Central Asia
; Tien Shan
英文摘要: Plate boundary evolution and interpreted paleogeography commonly involve the interaction between oceanic ridges and trenches. Western Junggar and Central-North Tianshan, NW China, have previously been regarded as independent orogens, but this model was challenged by the discovery of their similar tropic-subtropic coral assemblages and of Precambrian and Early Paleozoic clasts transmitted from the Central Tianshan in Early to Middle Paleozoic sediments in SW Junggar, suggesting they had been in contact by then. The presence of Late Silurian-Early Devonian adakitic rocks in northern SW Junggar was explained by slab roll-back, which required an active subducting slab in SW Junggar. However, this model is inconsistent with the cessation of arc magmatism immediately after the adakitic magmatism indicating there was no subduction in SW Junggar at those times. By re-evaluating the relevance of four diagnostic features of modern Californian ridge subduction, we propose a new model to explain the Late Silurian-Early Devonian orogenic framework of NW China in terms of sub-parallel ridge-trench interaction. The transmitted clasts from Central Tianshan in Early Paleozoic sediments in SW Junggar, at the same time as the Late Ordovician and Middle Silurian coral assemblages, and the complementary accretionary complex in SW Junggar and magmatic arc in Central Tianshan, are all contributary evidence for an Early Paleozoic subduction system. This subduction zone was intruded by two 446-380 Ma double magmatic belts: 1. A ridge subduction-generated adakitic gabbro-basalt-andesite-diorite-granite-rhyolite suite that intruded a 504-446 Ma accretionary complex in SW Junggar, and 2. a magmatic arc in Central Tianshan. A buoyant subducting ridge rifted and separated these magmatic belts resulting in the opening of a new 414-325 Ma ocean, which is preserved in OIB- and MORB-type ophiolites in southeastern SW Junggar and North Tianshan. These geological and geochemical relationships resemble those generated by oceanic spreading in the modern Gulf of California, which led to separation of magmatic belts in Baja California and mainland Mexico. The new ocean split the Central Tianshan magmatic arc from the Early Paleozoic Mt. Xiemisitai-Barleik-Mayile accretionary complex in SW Junggar, which changed to a new passive continental margin that led to deposition of Devonian shallow marine-terrestrial sediments, and to cessation of magmatism at 379-349 Ma. These features, including the Middle Paleozoic orogenic architecture and the geochemical properties of specific magmatic rocks, indicate the development of a Late Silurian-Early Devonian sub-parallel-to-trench ridge subduction. This model not only interprets phenomena mentioned in the above earlier models, but also reconciles unresolved spatial relationships between Western Junggar and the Tianshan. Subsequent closure of the new ocean and subduction of its ridge in the Late Paleozoic gave rise to the archipelagic framework that we see today in NW China. An analysis of worldwide examples of sub-parallel ridge-trench interaction demonstrates that a ridge can undergo multiple episodes of subduction before a terminal ocean closure. In this context our new tectonic model for the western Junggar and Tianshan regions may provide an improved understanding of the structure and evolution of ridge-subduction events in ancient orogenic belts. © 2021 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/166553
Appears in Collections: 气候变化与战略
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作者单位: State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, 100029, China; Innovation Academy for Earth Science, Chinese Academy of Sciences, China; University of Chinese Academy of Sciences, Beijing, 100049, China; Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi Xinjiang, 830011, China; Department of Earth and Environmental Sciences, California State University, Fresno, CA 93740, United States; School of Geography, Geology and the Environment, University of Leicester, Leicester, LE1 7RH, United Kingdom; Institute of Geology, Chinese Academy of Geological Sciences, Beijing, 100037, China
Recommended Citation:
Zhang J.,Chen Y.,Xiao W.,et al. Sub-parallel ridge-trench interaction and an alternative model for the Silurian-Devonian archipelago in Western Junggar and North-Central Tianshan in NW China[J]. Earth Science Reviews,2021-01-01,217