Crustal structure and inferred rifting processes in the northeast South China Sea

McIntosh, K. D.; Lavier, L. L.; Avendonk, H. J. Van; Lester, Ryan; Eakin, D. H.; Liu, Char‐Shine

doi:10.1016/j.marpetgeo.2014.03.012

Cited by 113 publications

(112 citation statements)

References 67 publications

Supporting

Mentioning

106

Contrasting

Order By: Relevance

“…However, in many areas, deep crustal reflections above the interpreted Moho are also visible. These reflections are similar to deep events interpreted in previous studies farther northeast and may mark the HVL (Lester et al, 2014).…”

Section: Accepted Manuscriptsupporting

confidence: 87%

“…Crustal thinning southeastward along these profiles also results in the southeastward step-wise shallowing of Moho depth from approximately 25 to 26 km below the shelf to 10 to 11 km below the oceanic basin. This observation is similar to previous investigations in the northern margin of the SCS (Nissen et al, 1995a;Yan et al, 2001;Huang et al, 2005;Wang et al, 2006;Hu et al, 2009;Wei et al, 2011;Ding et al, 2012;Lester et al, 2014).…”

supporting

confidence: 93%

“…Similar to the events described by Lester et al (2014), we suggest that reflector R2 is likely to be a seismic reflection interface at the top of an HVL. This is also consistent with the interpretation of Sun et al (2009) in their seismic profile.…”

Section: Deep Structuressupporting

confidence: 79%

“…North of this, a velocity profile of OBS1995 across the Hengchun Peninsula off SW Taiwan shows that 11-16-km-thick transitional crust subducts eastward beneath the Manila Trench (McIntosh et al, 2005(McIntosh et al, , 2013. Recent seismic reflection and wide-angle data indicate that the transitional crust at the northeastern margin of the SCS is highly extended with typical thicknesses of 7-15 km and is even hyper-extended (here, <4 km thick) in places (Van Avendonk et al, 2009;Pichot et al, 2013;Lester et al, 2014).…”

Section: Cot At the Mid-northern Margin Of The Scsmentioning

confidence: 90%

See 3 more Smart Citations

The continent–ocean transition at the mid-northern margin of the South China Sea

Gao

McIntosh

et al. 2015

Tectonophysics

Self Cite

View full text Add to dashboard Cite

Section: Accepted Manuscriptsupporting

confidence: 87%

supporting

confidence: 93%

Section: Deep Structuressupporting

confidence: 79%

Section: Cot At the Mid-northern Margin Of The Scsmentioning

confidence: 90%

See 2 more Smart Citations

The continent–ocean transition at the mid-northern margin of the South China Sea

Gao

McIntosh

et al. 2015

Tectonophysics

Self Cite

View full text Add to dashboard Cite

“…The lower crust is acoustically transparent and can be as thin as only ~6 km. Lower crust with a similar thickness and seismic appearance is reported from the northeastern SCS margin (McIntosh et al, , 2014Lester et al, 2013). The seaward continuation of this crustal layering into the COB zone is, however, ambiguous.…”

Section: Geological Settingmentioning

confidence: 66%

Expedition 367 Preliminary Report: South China Sea Rifted Margin

Sun¹,

Stock²,

Klaus³

2018

International Ocean Discovery Program Preliminary Report

View full text Add to dashboard Cite

International Ocean Discovery Program Expedition 367 is the first of two consecutive cruises that form the South China Sea Rifted Margin program. Expeditions 367 and 368 share the common key objectives of testing scientific hypotheses of breakup of the northern South China Sea (SCS) margin and comparing its rifting style and history to other nonvolcanic or magma-poor rifted margins. Four primary sites were selected for the overall program: one in the outer margin high (OMH) and three seaward of the OMH on distinct, margin-parallel basement ridges. These ridges are informally labeled A, B, and C within the continent-ocean transition (COT) zone going from the OMH to the steady-state oceanic crust of the SCS. The main scientific objectives include 1. Determining the nature of the basement within critical crustal units across the COT of the SCS that are critical to constrain style of rifting, 2. Constraining the time interval from initial crustal extension and plate rupture to the initial generation of igneous ocean crust, 3. Constraining vertical crustal movements during breakup, and 4. Examining the nature of igneous activity from rifting to seafloor spreading.In addition, sediment cores from the drill sites will provide information on the Cenozoic regional tectonic and environmental development of the Southeast Asia margin.Expedition 367 successfully completed operations at two of the four primary sites (Site U1499 on Ridge A and Site U1500 on Ridge B). At Site U1499, we cored to 1081.8 m in 22.1 days, with 52% recovery, and then logged downhole data from 655 to 1020 m. In 31 days at Site U1500, we penetrated to 1529 m, cored a total of 1012.8 m with 37% recovery, and collected log data from 842 to 1133 m. At each site we drilled to reach the depth of the main seismic reflector (acoustic basement), which prior to the expedition had been interpreted to be crystalline basement. Our objective was to determine which lithospheric layer constitutes the basement of the COT and whether there was middle or lower continental crust or subcontinental lithospheric mantle exhumed in the COT before the final lithospheric breakup. At Site U1499, coring ~200 m into the acoustic basement sampled sedimentary rocks, including early Miocene chalks underlain by pre-Miocene polymict breccias and poorly cemented gravels composed of sandstone pebbles and cobbles. Preliminary structural and lithologic analysis suggested that the gravels might be early synrift to prerift sediment. At Site U1500, the main seismic reflector corresponds to the top of a basalt sequence at ~1379.1 m. We cored 149.90 m into this volcanic package, recovering 114.92 m (77%) of sparsely to moderately plagioclase-phyric basalt comprising numerous lava flows including pillow lavas with glass, chilled margins, altered veins, hyaloclastites, and minor sediment. Preliminary geochemical analyses show that the basalt is tholeiitic. We speculate that the basalt might belong to the very early stage of magmatism prior to steady-state seafloor spreading (known as an "...

show abstract

Conjugate rifted margins width and asymmetry: The interplay between lithospheric strength and thermomechanical processes

2015

View full text Add to dashboard Cite

Numerical experiments have been used to relate the range in the distribution and the style of deformation observed in rifted margins to localizing/delocalizing thermomechanical processes. The experiments give rise to four end‐members of margins for varying initial lithospheric strength and extension rates. The first two end‐members are narrow and asymmetric and narrow and near‐symmetric, conjugate margins. The third end‐member is asymmetric conjugate margins, wherein one side is <100 km wide and the other is >100–300 km wide. Lastly, we explore wide rift systems that may form very asymmetric conjugate margins with one narrow margin and a very wide conjugate, 200 km to > 350 km across. With initial and boundary conditions close to that inferred from the North and South Atlantic margins, we find that not all margins experience a polyphase rifting history of stretching‐thinning‐exhumation. Instead, the stretching mode can be very short or protracted, and the thinning or the exhumation modes can be incomplete or absent. The deformation localization of the thinning mode is in places associated with the formation of a keystone block or “block H.” A new mechanism for the formation of the unstable crustal root under block H is described, wherein the bounding border faults lead to differential thinning of the crust and mantle lithosphere. Nonuniform extension also occurs in both types of wide rift systems and is related to the sequential deformation migration outward of an initial graben, associated with effective lithospheric strengthening that occurs during crustal thinning and bending.

show abstract

Crustal structure and inferred rifting processes in the northeast South China Sea

Cited by 113 publications

References 67 publications

The continent–ocean transition at the mid-northern margin of the South China Sea

The continent–ocean transition at the mid-northern margin of the South China Sea

Expedition 367 Preliminary Report: South China Sea Rifted Margin

Conjugate rifted margins width and asymmetry: The interplay between lithospheric strength and thermomechanical processes

Contact Info

Product

Resources

About