Tectonics of the North Qilian orogen, NW China
TL;DR: The Qilian Orogen at the northern margin of the Tibetan Plateau is a type suture zone that recorded a complete history from continental breakup to ocean basin evolution, and to the ultimate continental collision in the time period from the Neoproterozoic to the Paleozoic.
About: This article is published in Gondwana Research.The article was published on 2013-05-01. It has received 494 citations till now. The article focuses on the topics: Continental margin & Continental collision.
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TL;DR: The Phanerozoic evolution of the region is the result of more than 400 million years of continental dispersion from Gondwana and plate tectonic convergence, collision and accretion as discussed by the authors.
1,381 citations
TL;DR: In the last three decades, extensive geological, geochemical and geophysical investigations have been carried out on these cratonic blocks and intervening orogenic belts, producing an abundant amount of new data and competing interpretations.
617 citations
TL;DR: In this paper, the authors carried out geological and paleomagnetic investigations on East Asian blocks and associated orogenic belts, supported by a NSFC Major Program entitled “Reconstructions of East Asian Blocks in Pangea”.
533 citations
TL;DR: In this article, a model for the late Paleozoic (410-250 million years ago) is presented, together with a review of the underlying data, which can be used for numerical mantle modeling, and serve as a general framework for understanding late paleozoic tectonics.
Abstract: As the chronicle of plate motions through time, paleogeography is fundamental to our understanding of plate tectonics and its role in shaping the geology of the present-day. To properly appreciate the history of tectonics—and its influence on the deep Earth and climate—it is imperative to seek an accurate and global model of paleogeography. However, owing to the incessant loss of oceanic lithosphere through subduction, the paleogeographic reconstruction of ‘full-plates’ (including oceanic lithosphere) becomes increasingly challenging with age. Prior to 150 Ma ∼60% of the lithosphere is missing and reconstructions are developed without explicit regard for oceanic lithosphere or plate tectonic principles; in effect, reflecting the earlier mobilistic paradigm of continental drift. Although these ‘continental’ reconstructions have been immensely useful, the next-generation of mantle models requires global plate kinematic descriptions with full-plate reconstructions. Moreover, in disregarding (or only loosely applying) plate tectonic rules, continental reconstructions fail to take advantage of a wealth of additional information in the form of practical constraints. Following a series of new developments, both in geodynamic theory and analytical tools, it is now feasible to construct full-plate models that lend themselves to testing by the wider Earth-science community. Such a model is presented here for the late Paleozoic (410–250 Ma) together with a review of the underlying data. Although we expect this model to be particularly useful for numerical mantle modeling, we hope that it will also serve as a general framework for understanding late Paleozoic tectonics, one on which future improvements can be built and further tested.
454 citations
TL;DR: In this paper, the Proto-Tethys Ocean is defined as a complex complex paleo-ocean located between the Tarim-North China and the Sibumasu/Baoshan blocks, and it was opened from the rifting of the Supercontinent Rodinia and mainly closed at the end of the Early Paleozoic.
424 citations
References
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01 Jan 1989
TL;DR: In this article, trace-element data for mid-ocean ridge basalts and ocean island basalts are used to formulate chemical systematics for oceanic basalts, interpreted in terms of partial-melting conditions, variations in residual mineralogy, involvement of subducted sediment, recycling of oceanic lithosphere and processes within the low velocity zone.
Abstract: Summary Trace-element data for mid-ocean ridge basalts (MORBs) and ocean island basalts (OIB) are used to formulate chemical systematics for oceanic basalts. The data suggest that the order of trace-element incompatibility in oceanic basalts is Cs ≈ Rb ≈ (≈ Tl) ≈ Ba(≈ W) > Th > U ≈ Nb = Ta ≈ K > La > Ce ≈ Pb > Pr (≈ Mo) ≈ Sr > P ≈ Nd (> F) > Zr = Hf ≈ Sm > Eu ≈ Sn (≈ Sb) ≈ Ti > Dy ≈ (Li) > Ho = Y > Yb. This rule works in general and suggests that the overall fractionation processes operating during magma generation and evolution are relatively simple, involving no significant change in the environment of formation for MORBs and OIBs. In detail, minor differences in element ratios correlate with the isotopic characteristics of different types of OIB components (HIMU, EM, MORB). These systematics are interpreted in terms of partial-melting conditions, variations in residual mineralogy, involvement of subducted sediment, recycling of oceanic lithosphere and processes within the low velocity zone. Niobium data indicate that the mantle sources of MORB and OIB are not exact complementary reservoirs to the continental crust. Subduction of oceanic crust or separation of refractory eclogite material from the former oceanic crust into the lower mantle appears to be required. The negative europium anomalies observed in some EM-type OIBs and the systematics of their key element ratios suggest the addition of a small amount (⩽1% or less) of subducted sediment to their mantle sources. However, a general lack of a crustal signature in OIBs indicates that sediment recycling has not been an important process in the convecting mantle, at least not in more recent times (⩽2 Ga). Upward migration of silica-undersaturated melts from the low velocity zone can generate an enriched reservoir in the continental and oceanic lithospheric mantle. We propose that the HIMU type (eg St Helena) OIB component can be generated in this way. This enriched mantle can be re-introduced into the convective mantle by thermal erosion of the continental lithosphere and by the recycling of the enriched oceanic lithosphere back into the mantle.
19,221 citations
University of Western Australia1, Curtin University2, Lund University3, University of Adelaide4, Geological Survey of Canada5, Carleton University6, University of Brasília7, University of Bergen8, University of New Mexico9, Macquarie University10, Stockholm University11, University of Copenhagen12, Russian Academy of Sciences13
TL;DR: A brief synthesis of the current state of knowledge on the formation and break-up of the early Neoproterozoic supercontinent Rodinia and the subsequent assembly of Gondwanaland is presented in this paper.
2,790 citations
"Tectonics of the North Qilian oroge..." refers background in this paper
...~750 Ma as a result of Rodinia disintegration (e.g. Meert, 2003; Torsvik, 2003; Li et al., 2008)....
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TL;DR: In this paper, a table of mineral-liquid distribution coefficients for Ti, Zr, Y, and Nb for basic, intermediate and acid melt compositions were used to interpret variations of these elements, first in basalts and second during fractional crystallization from basic to acid magmas.
Abstract: Data from experimental runs, coexisting phases in ultramafic rocks and phenocryst-matrix pairs in volcanic rocks have been used to compile a table of mineral-liquid distribution coefficients for Ti, Zr, Y, and Nb for basic, intermediate and acid melt compositions. These values have then been used to interpret variations of these elements, first in basalts and second, during fractional crystallization from basic to acid magmas. For basalts, petrogenetic modelling of Zr/Y, Zr/Ti, and Zr/Nb ratios, when used in conjunction with REE, Cr and isotopic variations, suggests that: (1) the increase in Zr/Y ratio from mid-ocean ridge to within plate basalts and the low Zr/Nb ratios of alkalic basalts are due to (fluid controlled) source heterogeneities; (2) the low Zr and Zr/Y ratio of volcanic arc basalts results from high degree of partial melting of a depleted source; and (3) the high Zr and similar Zr/Y ratio of basalts from fast spreading relative to slow spreading ridges results from open-system fractional crystallization. Modelling of fractionation trends in more evolved rocks using Y-Zr, Ti-Zr and Nb-Zr diagrams highlights in particular the change in crystallizing mafic phases from island arcs (clinopyroxene-dominated) to Andean-type arcs (amphibole±biotite-dominated). These methods can be applied to altered lavas of unknown affinities to provide additional information on their genesis and eruptive environment.
2,680 citations
"Tectonics of the North Qilian oroge..." refers background in this paper
...Zr/Y (Pearce and Norry, 1979), most basalt and dolerite samples plot across the MORB, VAB and WPB fields....
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...V (Shervais, 1982) and Zr vs. Zr/Y (Pearce and Norry, 1979), most basalt and dolerite samples plot across the MORB, VAB and WPB fields....
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...All mafic volcanic rocks are characterized by LREE enriched patterns with high (LaN/ YbN) (2.8–8.1), Th/Nb (0.75–2.60), Th/La (0.30–0.87), and La/Nb (2.0–3.0) ratios, resembling volcanic arc basalts in the present-day supra-subduction zone environment (e.g., Pearce and Norry, 1979)....
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TL;DR: In this article, the authors applied the Ti/V plot to published data on ophiolites from a variety of postulated settings and in general supported the conclusions of previous investigators.
2,056 citations
"Tectonics of the North Qilian oroge..." refers background in this paper
...V (Shervais, 1982) and Zr vs. Zr/Y (Pearce and Norry, 1979), most basalt and dolerite samples plot across the MORB, VAB and WPB fields....
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