Formation of ophiolite-bearing tectono-sedimentary mélanges in accretionary wedges by gravity driven submarine erosion: Insights from analogue models and case studies

Malavieille, Jacques; Molli, Giancarlo; Genti, Manon; Dominguez, Stéphane; Beyssac, Olivier; Taboada, Alfredo; Brovarone, Alberto Vitale; Chang-yi, LU; Chen, Chih Tung

doi:10.1016/j.jog.2016.05.008

Cited by 43 publications

(58 citation statements)

References 105 publications

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“…The geochemistry and chronology of these accreted mafic rocks are critical indicators of the provenance and geodynamic evolution of the accretionary prism and can help constrain the regional magmatic history and nature of the mantle around the convergent boundary. However, direct studies of these accreted basalts are quite limited (H. Y. Chen et al, ; Page & Lan, ; Pelletier & Stephan, ), and interpretations of their provenance based on the paleobiology of their accompanying sediments, structural analysis, and regional geophysics remain speculative and controversial (Byrne, ; C. P. Chang et al, ; C. Y. Huang, ; Malavieille et al, ; X. C. Zhang et al, ). In early studies, accreted basaltic rocks were often regarded as fragments of the oceanic crust of the SCS (C. Y. Huang et al, ; Muller et al, ; Page & Lan, ; Pelletier & Stephan, ).…”

Section: Introductionmentioning

confidence: 99%

Geochemistry and Geochronology of the Accreted Mafic Rocks From the Hengchun Peninsula, Southern Taiwan: Origin and Tectonic Implications

et al. 2019

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The accretionary prism of the Hengchun Peninsula at the southernmost tip of the active Taiwan orogen has newly emerged due to the transition from a subduction zone to an arc‐continent collision zone. The mafic rocks within the Hengchun accretionary prism, whose provenance has long been controversial, are highly indicative of the mantle nature and tectonic evolution around the northern Manila Trench. Based on geochemical analyses, the accreted basalts are classified as normal and enriched mid‐ocean ridge basalts (N‐MORB and E‐MORB) and alkaline ocean island basalts. The N‐MORBs, which exhibit geochemical signatures indicative of virtually unmetasomatized depleted MORB mantle and yield zircon U‐Pb ages of 22.8 ± 0.3 and 24.2 ± 1.1 Ma, were off‐scraped from the subducted oceanic crust of the South China Sea (SCS). The alkaline ocean island basalts are considered fragments of subducted seamount due to their geochemical similarity with seamount basalts from the SCS. The Hf‐Nd isotopic compositions of basalts from the north SCS may represent the contributions of recycled oceanic crust and the upwelling Hainan Plume. The E‐MORBs, which exhibit similar geochemical compositions as rocks from the Huatung Basin and yield an 40Ar/39Ar age of 135.0 ± 5.6 Ma, were removed from the overriding plate due to the excessive shear stress between the converging plates and were laterally transported by strike‐slip movement; alternatively, they were off‐scraped from the subducted Luzon forearc slices. The temporary uplift and collapse of the accretionary prism caused by seamount subduction may have been responsible for the genesis of the lenticular Shihmen Conglomerate.

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Section: Introductionmentioning

confidence: 99%

Geochemistry and Geochronology of the Accreted Mafic Rocks From the Hengchun Peninsula, Southern Taiwan: Origin and Tectonic Implications

et al. 2019

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“…Later studies demonstrate that these stratified sedimentary rock occurrences are limited in their lateral extent, and that they represent exotic blocks of sedimentary broken formation, that were likely forearc basement incorporated into the mélange by two tectonic thrusting events during arc‐continent collision (Chang et al, , ; W. H. Chen et al, ; Huang et al, , ). The retrowedge evolution model is proposed to reconcile conflicting interpretations of the olistostrome model and the tectonic collision model (Chi et al, ; Malavieille et al, ).…”

Section: Introductionmentioning

confidence: 99%

Geochemical and Geochronological Constraints on the Origin and Emplacement of the East Taiwan Ophiolite

Lin

Harris

Sun

et al. 2019

Geochem Geophys Geosyst

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The East Taiwan Ophiolite (ETO) occurs as blocks and thrust sheets associated with the Lichi Mélange in the Coastal Range of eastern Taiwan. The blocks consist of serpentinized harzburgite, serpentinite breccia, gabbro, dikes of dolerite and plagiogranite, pillow basalts, and red clay within a mud‐ and serpentinite‐rich mélange matrix. New U‐Pb zircon dating of a pegmatite gabbro yields a weighted mean age of 16.65 ± 0.20 Ma. This age is earlier than the North Luzon Arc but overlaps with the late‐stage spreading of the South China Sea. ETO glassy basalt has low K2O, MgO and high CaO contents, similar to MORB. REE and trace element patterns show both N‐MORB patterns with LREE depletion and E‐MORB patterns with slight LREE enrichment. A few samples show slight depletion in Nb‐Ta and Ti and enrichment in Rb, Ba, U and Sr, indicating a hint of subduction influence. Most ETO basalt plots within the overlapping fields of N‐MORB and BABB on Ti‐V, Cr‐Y, Nb/Yb‐Th/Yb, and Hf/3‐Th‐Ta discrimination diagrams. These geochemical compositions are emblematic of mid‐ocean ridge or back‐arc lava, like South China Sea basalt. We interpret ETO basalt and gabbro as fragments of the subducted South China Sea basement that were scrapped off and accreted to the Luzon forearc during the process of subduction initiation along the Manila Trench. Blocks of mantle material in the mélange may originate from the upper plate of the arc‐continent collision and were mixed with lower plate crustal material in a subduction channel now represented by the Lichi Mélange.

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“…The Kenting Mélange, which only outcrops east of the Hengchun Basin, is known as a tectonic mélange (e.g., Tsan, 1974;Page and Lan, 1983;Huang, 1984;Pelletier and Stephan, 1986;Huang et al, 1997;Chang et al, 2003Chang et al, , 2009aDeffontaines et al, 2016;Zhang et al, 2016;Malavieille et al, 2016). It is interpreted as a chaotic tectonostratigraphic unit containing blocks of various origin (ophiolitic and sedimentary), size and lithology embedded in a sedimentary matrix (Malavieille et al, 2016).…”

Section: Hengchun Geological State Of the Artmentioning

confidence: 99%

“…It is interpreted as a chaotic tectonostratigraphic unit containing blocks of various origin (ophiolitic and sedimentary), size and lithology embedded in a sedimentary matrix (Malavieille et al, 2016). It is herein interpreted as a large tectonic breccia of composite ages that ranges from 1 to 10 Ma (see Malavieille et al, 2016) as it mixes various sizes of different blocks and different turbiditic and shale bodies (Page and Lan, 1983;Lin and Wang, 2001;Chang et al, 2003). In our opinion, this shaly, blocky tectonic mélange is injected (intruded) within the major fault zones south of Taiwan due to both the plate convergence and high pressure of fluids at depth (see also Deffontaines et al, 2016).…”

Section: Hengchun Geological State Of the Artmentioning

confidence: 99%

“…In our opinion, this shaly, blocky tectonic mélange is injected (intruded) within the major fault zones south of Taiwan due to both the plate convergence and high pressure of fluids at depth (see also Deffontaines et al, 2016). Future scientific work is needed regarding the differing, incompatible assumptions and hypotheses in order to both characterize the processes that create this tectonic Kenting Mélange and to reconstruct (or inverse) its evolution through time (see synthesis in Malavieille et al, 2016).…”

Section: Hengchun Geological State Of the Artmentioning

confidence: 99%

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Active tectonics of the onshore Hengchun Fault using UAS DSM combined with ALOS PS-InSAR time series (Southern Taiwan)

Deffontaines

Chang

Champenois³

et al. 2018

Nat. Hazards Earth Syst. Sci.

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Abstract. Characterizing active faults and quantifying their activity are major concerns in Taiwan, especially following the major Chichi earthquake on 21 September 1999. Among the targets that still remain poorly understood in terms of active tectonics are the Hengchun and Kenting faults (Southern Taiwan). From a geodynamic point of view, the faults affect the outcropping top of the Manila accretionary prism of the Manila subduction zone that runs from Luzon (northern Philippines) to Taiwan. In order to better locate and quantify the location and quantify the activity of the Hengchun Fault, we start from existing geological maps, which we update thanks to the use of two products derived from unmanned aircraft system acquisitions: (1) a very high precision (< 50 cm) and resolution (< 10 cm) digital surface model (DSM) and (2) a georeferenced aerial photograph mosaic of the studied area. Moreover, the superimposition of the resulting structural sketch map with new Persistent Scatterer Interferometric Synthetic Aperture Radar (PS-InSAR) results obtained from PALSAR ALOS images, validated by Global Positioning System (GPS) and leveling data, allows the characterization and quantification of the surface displacements during the monitoring period (2007)(2008)(2009)(2010)(2011). We confirm herein the geometry, characterization and quantification of the active Hengchun Fault deformation, which acts as an active leftlateral transpressive fault. As the Hengchun ridge was the location of one of the last major earthquakes in Taiwan (26 December 2006, depth: 44 km, M L = 7.0), Hengchun Peninsula active tectonics must be better constrained in order if possible to prevent major destructions in the near future.

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Formation of ophiolite-bearing tectono-sedimentary mélanges in accretionary wedges by gravity driven submarine erosion: Insights from analogue models and case studies

Cited by 43 publications

References 105 publications

Geochemistry and Geochronology of the Accreted Mafic Rocks From the Hengchun Peninsula, Southern Taiwan: Origin and Tectonic Implications

Geochemistry and Geochronology of the Accreted Mafic Rocks From the Hengchun Peninsula, Southern Taiwan: Origin and Tectonic Implications

Geochemical and Geochronological Constraints on the Origin and Emplacement of the East Taiwan Ophiolite

Active tectonics of the onshore Hengchun Fault using UAS DSM combined with ALOS PS-InSAR time series (Southern Taiwan)

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