OIB- and P-type ophiolites along the Yarlung- Zangbo Suture Zone (YZSZ), Southern Tibet: Poly- Phase melt history and mantle sources of the Neotethyan oceanic lithosphere

Yang, Gaoxue; Dilek, Yıldırım

doi:10.18814/epiiugs/2015/v38i4/82420

Cited by 38 publications

(8 citation statements)

References 93 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Some of the best examples of CM ophiolites include the Jurassic ophiolites in the Ligurian units of the Northern Apennines (e.g., Montanini et al, 2008;Marroni and Pandolfi, 2007), Alpine Corsica (Durand-Delga, 1984;Malavieille et al, 1998;Saccani et al, 2008a), and the Western Alps (Lagabrielle and Cannat, 1990;Desmurs et al, 2002;Rampone et al, 2005;Manatschal and Müntener, 2009; Microcontinent. et al, 2015;Balestro et al 2015;), and the early Cretaceous Dongba-Purang ophiolites in southern Tibet (Liu et al, 2015;Yang and Dilek, 2015). However, many more CM ophiolites are yet to be documented in the Phanerozoic and Precambrian orogenic belts through systematic structural field and geochemical studies.…”

Section: Introductionmentioning

confidence: 99%

Continental Margin Ophiolites of Neotethys: Remnants of Ancient Ocean–Continent Transition Zone (OCTZ) Lithosphere and Their Geochemistry, Mantle Sources and Melt Evolution Patterns

Saccani¹

2015

Episodes

View full text Add to dashboard Cite

We present an overview of the geology, geochemistry and petrogenesis of continental margin ophiolites (CMO), which represent the lithospheric remnants of riftgenerated paleo ocean -continent transition zones (OCTZ) in orogenic belts. The igneous stratigraphy and geochemical signatures of Neotethyan CMOs reflect the extent of geochemical heterogeneity, partial melting degrees, and melt evolution patterns in the continental lithospheric mantle prior to the onset of seafloor spreading in rifted margins. Basaltic rocks of the Jurassic CMOs in the External Ligurian units of the Northern Apennines have N-MORB and G-MORB affinities with strong HREE/MREE depletion, and represent the products of partial melting of a heterogeneous subcontinental lithospheric mantle containing small volumes of garnet pyroxenite layers. These extrusive rocks were erupted directly on the exhumed fertile spinel lherzolites of Adria during its OCTZ evolution. Volcanic rocks of the Triassic CMOs in the Albanide-Hellenide orogenic belt are represented by calc-alkaline suites; alkaline basalts and subordinate trachybasalts, trachyandesites, and trachytes; transitional to sub-alkaline plume-type P-MORB basalts; sub-alkaline enriched, E-MORB basalts; and, sub-alkaline N-MORB basalts. Upper mantle peridotites are not exposed. Magmas of these extrusive rock associations were derived from compositionally distinct mantle sources, which were affected by previous subduction and plume events in the geological history of the region. The CMOs in the Zagros orogenic belt include metamorphosed lherzolites with gabbro and mafic dike intrusions, which show N-MORB and G-MORB affinities. Basalts and basaltic andesites making up the majority of the Zagros volcanic sequences have E-MORB and P-MORB affinities, whereas minor alkaline rocks that are composed of basalts, trachybasalts and trachytes display OIB signatures. The mantle sources of the Zagros CMOs were progressively enriched in Th and Nb. The OIB component of the mantle beneath the Zagros OCTZ was derived from previous plume events during the early Carboniferous, when Paleotethys was undergoing its rift-drift tectonics. The observed differences in the igneous stratigraphy and geochemical affinities of these Neotethyan CMOs are a result of extreme mantle heterogeneity caused by previous subduction and plume events during the Wilson Cycle evolution of the older Paleotethys.

show abstract

Section: Introductionmentioning

confidence: 99%

Continental Margin Ophiolites of Neotethys: Remnants of Ancient Ocean–Continent Transition Zone (OCTZ) Lithosphere and Their Geochemistry, Mantle Sources and Melt Evolution Patterns

Saccani¹

2015

Episodes

View full text Add to dashboard Cite

show abstract

“…Plume-type ophiolitic rocks occur extensively within the entire Alpine-Tibetan orogenic system and are interpreted to have formed from plume-metasomatized asthenospheric mantle sources during the early stages of the opening of Neotethyan seaways between Laurasia and Gondwana-derived continental bodies ( Fig. 2; Dilek, 2003a;Saccani et al, 2015;Yang and Dilek, 2015). Recovery of microdiamonds and UHP and crustal minerals from mid-ocean ridgeand plume-type ophiolitic peridotites would show that superplumes play a significant role in effectively transporting MTZ material to shallow mantle partial melting factories beneath oceanic and continental rifts.…”

Section: Outstanding Questionsmentioning

confidence: 99%

Ophiolites, diamonds, and ultrahigh-pressure minerals: New discoveries and concepts on upper mantle petrogenesis

Dilek¹,

Yang²

2018

Lithosphere

Self Cite

View full text Add to dashboard Cite

Ophiolitic peridotites represent variously depleted residues of the primitive mantle after multiple episodes of partial melting, melt extraction, and melt-rock interactions. They display a wide range of compositional and geochemical heterogeneities at different scales, and their incompatible bulk-rock compositions and mineral chemistries are commonly inconsistent with their evolution through simple partial melting processes at shallow mantle depths. Approaching these issues from different perspectives, the papers in this volume concentrate on (1) melt evolution and magmatic construction of ophiolites in various tectonic settings, and (2) the occurrence of microdiamonds, ultrahigh-pressure (UHP) minerals, and crustal material as inclusions in ophiolitic chromitites and peridotites. Crustal and mantle rock units exposed in different ophiolites show that the mantle melt sources of ophiolitic magmas undergo progressive melting, depletion, and enrichment events, constantly modifying the melt compositions and the mineralogical and chemical makeup of residual peridotites. Formation and incorporation of microdiamonds and UHP minerals into chromite grains occurs at depths of 350-660 km in highly reducing conditions of the mantle transition zone. Carbon for microdiamonds and crustal minerals are derived from subduction-driven recycling of surface material. Host peridotites with their UHP mineral and diamond inclusions are transported into shallow mantle depths by asthenospheric upwelling, associated with either slab rollback-induced channel flow or superplumes. Decompression melting of transported mantle rocks beneath oceanic spreading centers and their subsequent flux melting in mantle wedges result in late-stage formation of podiform chromitites during the upper mantle petrogenesis of ophiolites. Future studies should demonstrate whether diamonds and UHP minerals also occur in peridotites and chromitites of nonsubduction-related ophiolites.

show abstract

“…The evolution proposed for the Upper Units implies that the Variscan suture ophiolites were generated within the Rheic Ocean realm. The Cambrian ophiolites, excepting the Bazar Ophiolite, would be linked to the initial stages of the opening of this ocean reminiscent of the Western Alps Tethys (Dilek and Furnes, 2014;Balestro et al 2015;Saccani et al 2015), whereas the Devonian ophiolites would have originated during the final stages of its closure (Arenas et al, 2007a) analogous to many supra-subduction zone ophiolites (Dilek, 2003;Dilek and Furnes, 2011;Yang et al 2015). The Devonian ophiolites, the commonest in the Variscan suture, have been interpreted as suprasubduction zone ophiolites generated at the intra-Rheic subduction zone located near the Southern margin of Laurussia (Díaz García et al, 1999;Sánchez Martínez et al, 2007a).…”

Section: Paleozoic Oceans and The Assembly Of Pangeamentioning

confidence: 99%

Variscan ophiolites in NW Iberia: Tracking Lost Paleozoic Oceans and the Assembly of Pangea

Arenas¹

2015

Episodes

View full text Add to dashboard Cite

OIB- and P-type ophiolites along the Yarlung- Zangbo Suture Zone (YZSZ), Southern Tibet: Poly- Phase melt history and mantle sources of the Neotethyan oceanic lithosphere

Cited by 38 publications

References 93 publications

Continental Margin Ophiolites of Neotethys: Remnants of Ancient Ocean–Continent Transition Zone (OCTZ) Lithosphere and Their Geochemistry, Mantle Sources and Melt Evolution Patterns

Continental Margin Ophiolites of Neotethys: Remnants of Ancient Ocean–Continent Transition Zone (OCTZ) Lithosphere and Their Geochemistry, Mantle Sources and Melt Evolution Patterns

Ophiolites, diamonds, and ultrahigh-pressure minerals: New discoveries and concepts on upper mantle petrogenesis

Variscan ophiolites in NW Iberia: Tracking Lost Paleozoic Oceans and the Assembly of Pangea

Contact Info

Product

Resources

About