Discovery of a hidden Triassic Arc in the Southern South China Sea: Evidence for the breakaway of a ribbon continent with implications for the evolution of the Western Pacific margin

Terra Nova ◽  
2021 ◽  
Author(s):  
Wu Wei ◽  
Chuan‐Zhou Liu ◽  
Yi‐Fei Hou ◽  
Cheng‐Long Deng ◽  
Wen Yan ◽  
...  
Keyword(s):  
South China Sea ◽  
South China ◽  
Western Pacific ◽  
Southern South China Sea ◽  
China Sea ◽  
Pacific Margin ◽  
The Western Pacific

An Expendable Microstructure Profiler for Deep Ocean Measurements

2017 ◽  
Vol 34 (1) ◽  
pp. 153-165 ◽  
Author(s):  
Xiaodong Shang ◽  
Yongfeng Qi ◽  
Guiying Chen ◽  
Changrong Liang ◽  
Rolf G. Lueck ◽  
...  
Keyword(s):  
Pacific Ocean ◽  
South China Sea ◽  
South China ◽  
Deep Ocean ◽  
Western Pacific ◽  
Western Pacific Ocean ◽  
Southern South China Sea ◽  
China Sea ◽  
Dissipation Rates ◽  
The Western Pacific

AbstractMeasurements of turbulence in the deep ocean, particularly close to the bottom, are extremely sparse because of the difficulty and operational risk of obtaining deep profiles near the seafloor. A newly developed expendable instrument—the VMP-X (Vertical Microstructure Profiler–Expendable)—carries two microstructure shear probes to measure the fluctuations of vertical shear into the dissipation range and can profile down to a depth of 6000 m. Data from nine VMP-X profiles in the western Pacific Ocean near 11.6°N over rough topography display bottom-intensified turbulence with dissipation rates increasing by two factors of 10 to 4 W kg−1 within 200 m above the bottom. In contrast, over smooth topography in the southern South China Sea near 11°N, three profiles show that turbulence in the bottom boundary layer increases only slightly, with dissipation rates reaching 1 W kg−1. The eddy diffusivity over rough topography reached to 5 m2 s−1. The average diffusivity over all depths was 0.3 and 0.9 m2 s−1 for the tests in the southern South China Sea and in the western Pacific Ocean, respectively, and these values are much larger than previous estimates of less than ≈0.1 m2 s−1 for the main thermocline.

Impacts of the Madden-Julian Oscillation on South China Sea Monsoon

2020 ◽  
Author(s):  
Qun Zhou ◽  
Lixin Wei
Keyword(s):  
South China Sea ◽  
South China ◽  
Meridional Circulation ◽  
East Asian ◽  
Winter Monsoon ◽  
Western Pacific ◽  
Madden Julian Oscillation ◽  
China Sea ◽  
The Western Pacific ◽  
Local Meridional Circulation

Abstract It is of great practical importance to understand the variability of the South China Sea (SCS) monsoon on intraseasonal time scales, since the anomalous enhancement of the SCS monsoon may exert serious impacts on the safety of offshore engineering and marine transportation. Our composite analysis shows that the SCS surface wind anomalies are considerably varying with the Madden-Julian Oscillation (MJO) eastward propagation. The SCS summer southwest monsoon tends to be stronger (weaker) in phases 5–8 (1–4) of MJO with the largest positive (negative) wind-speed anomalies when the MJO convection is centered in the western Pacific (far western Indian Ocean), suggesting the highest (lowest) probability of the gale over the SCS. The variation of the western Pacific Subtropical High (WPSH), induced by the variations of the local meridional circulation, is shown to play a crucial role in the MJO-SCS summer monsoon linkage. The SCS winter monsoon is also shown to be modulated by the MJO with strengthened (weakened) surface northeasterly in phases 5–6 (1–2). The extra-tropical East Asian trough and East Asian westerly jet associated with the local meridional circulation can well explain the changes of the MJO-SCS winter monsoon relationship. The opposite responses of the wind direction during the same phases of the MJO between summer and winter may be attributed to the discrepancy of meridional circulation related to the wintertime equatorward shift of the MJO convection. The present study indicates that the MJO could be taken into consideration when applying extended-range weather forecast over the SCS as the predictability of the MJO activity is up to 15–20 day currently.

scholarly journals The South China Sea: A Geopolitical Analysis

2016 ◽  
Vol 8 (3) ◽  
pp. 14
Author(s):  
Martin D Mitchell
Keyword(s):  
South China Sea ◽  
South China ◽  
The United States ◽  
The South China Sea ◽  
Western Pacific ◽  
The South ◽  
China Sea ◽  
Geographic Setting ◽  
Territorial Water ◽  
The Western Pacific

Since 1945 the South China Sea and the western Pacific has functioned as an uncontested global common patrolled by overwhelming U.S. naval and air power projected from a series of peripheral and over the horizon bases. The dramatic rise of China alters this situation and has transformed the South China Sea into a frontier of control as China seeks to morph this maritime theater into a landward extension of the Chinese coast where it can deploy land-based tactics into an arena previously dominated by maritime power and tactics to secure the South China Sea as a de facto territorial water that serves multiple Chinese strategic interests. Hence, the attempt by a land-based Eurasian power (China) to carve a permanent bridgehead into Spykman’s Eurasian maritime periphery. Against, this trend the United States has countered with President Obama’s Asian Pivot. However, the implementation of the Asian Pivot is limited by several post Cold War developments and certain constraints inherent in the geographic setting of the South China Sea. Beyond the South China Sea, the geographic setting favors the U.S. and its allies. Consequently, American options acting singly or in coalition with other nations, most notably Japan and Australia, remain more flexible and able to serve as a long term counterweight to Chinese force projection capabilities into the western Pacific proper. 

Western Pacific marginal basin plate tectonics: overview, questions, and insights from mantle structure

2020 ◽  
Author(s):  
Jonny Wu ◽  
John Suppe
Keyword(s):  
South China Sea ◽  
South China ◽  
Subduction Zones ◽  
Plate Tectonics ◽  
Western Pacific ◽  
Mantle Structure ◽  
Equatorial Latitude ◽  
China Sea ◽  
Marginal Seas ◽  
The Western Pacific

<p>The western Pacific marginal basins are a collage of plates and marginal seas that primarily formed in the Cenozoic and occupy the complex tectonic area between the converging major Eurasian, Indo-Australian and Pacific plates.  Strongly contrasting plate tectonic reconstructions continue to be proposed for this region.  Here we review current plate models, key questions, and highlight recent insights from mantle structure studies. </p><p>The Philippine Sea plate (PSP) is one of the largest marginal seas in the region.  The plate is currently moving WNW, in a similar orientation to the Pacific and Caroline plates.  Multiple studies show that PSP plate tectonics are key to unravelling the history of the region, for several reasons: (1) the PSP is far-travelled; paleomagnetism indicates relatively rapid (5.5 cm/yr) PSP northward motions since the Eocene from a near-equatorial latitude; (2) PSP tectonic histories imply interactions with many surrounding plates and regions, including the South China Sea (SCS), Taiwan, Japan, the western Pacific, and other smaller plates or fragments (i.e. Luzon or Celebes Sea); (3) the pre-subduction size of the PSP is not well-established because most of the plate is surrounded by subduction zones.  We review recent studies that attempt to ‘unsubduct’ the PSP from tomography and discuss their regional implications.</p><p>Another key but highly controversial topic is South China Sea (PSCS) formation and associated proto-South China Sea (PSCS) disappearance, if such a plate had existed.  The most popular proto-South China Sea plate model invokes southward subduction of the proto-South China Sea beneath NW Borneo during the Cenozoic.  Although southward PSCS subduction is most consistent with our current geological understanding, the regional mantle structure does not easily fit with this model; other scenarios may be possible.  In particular, it has not been straightforward for the southward PSCS model to explain the origin of sub-horizontal slabs under the present SCS at relatively shallow (500 to 800 km) depths.  We show an alternative ‘double-sided’ PSCS subduction model that produces testable hypotheses for future NW Borneo studies. </p><p>Finally, the Caroline Sea plate has an enigmatic history but is important for understanding the southern Marianas, Yap and Palau trenches.  We first review previous evidence for a ‘Caroline hotspot track’ and overlapping LIPs that traverse the northern Caroline plate.  We link these features to an imaged lower mantle plume and show their implications for Caroline-Pacific plate motions since the latest Eocene. </p>

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