Lower Yangtze drainage reorganization response to western Pacific Subduction

2020 ◽  
Author(s):  
Ping Wang ◽  
Hongbo Zheng ◽  
Yongdong Wang ◽  
Xiaochun Wei ◽  
Lingyu Tang ◽  
...  
Keyword(s):  
East Asia ◽  
Active Role ◽  
Pacific Plate ◽  
Western Pacific ◽  
Surface Processes ◽  
Silty Clay ◽  
Lithospheric Deformation ◽  
The Pacific ◽  
Lower Yangtze ◽  
Early Cenozoic

<p>The evolution of the longest river in Asia, Yangtze, provides a spectacular example to understand the Cenozoic interaction between tectonic, climate and surface processes. The oldest Yangtze deposits in southeast China, characterized by thick sequence of unconsolidated gravel, sand and silty clay, referred as “Yangtze Gravel”, has been recently found in its lower reach and dated back to > 23 Ma, indicating a pre-Miocene establishment of a through-going river. However, the link between river reorganization and tectonic evolution has never been well understood. Far-field effects of the Indian–Eurasia collision are often invoked to explain the widespread East Asia lithospheric deformations and the opening of the marginal, as well as the through-going of the large rivers. However,  some geological and geophysical investigations challenge this model and suggest that the Pacific Plate subduction beneath Eurasia plays an much more active role in East Asia lithospheric deformation during the Cenozoic. Here, we study the sedimentology, chronology and provenance of the Yangtze Gravel based on 17 stratigraphic sections exposed along the Lower Yangtze River. Our results indicate a braided alluvial system (Paleo-Lower Yangtze) established since early Miocene across the Jianghan Basin, North Jiangsu Basin and East China Sea Shelf Basin. Compared with the Early Cenozoic red-colored, halite-bearing lacustrine deposits, our results indicate a larger tectonically controlled shift from rifting to post-rift down-warping across these basins. During Early Cenozoic, the initial subduction of Pacific Plate may contribute to the back-arc extension and affect the continental deep interior of East Asia many thousands of kilometers from the subduction margin. During Oligocene to Miocene, the ongoing subduction of the Pacific plate produced a stagnant slab that may have significantly triggered the post-rift subsidence and the connection of these basins. The deposition of the “Yangtze Gravel” reflect the dynamic response of surface processes to western Pacific subduction in East Asia.</p>

Asian and south-western Pacific continental terranes derived from Gondwana, and their biogeographic significance

1991 ◽  
Vol 4 (1) ◽  
pp. 13 ◽  
Author(s):  
C Burrett ◽  
N Duhid ◽  
R Berry ◽  
R Varne
Keyword(s):  
East Asia ◽  
Late Miocene ◽  
Western Pacific ◽  
South East Asia ◽  
Pacific Region ◽  
The Pacific ◽  
Australian Continent

The recent recognition of numerous small geological terranes in the Indo-Pacific region has revolutionised our understanding of geological and biogeographic processes. Most of these terranes rifted from Gondwana. The Shan-Thai terrane rifted from Australia in the Permian and collided with Indo-China in the Triassic. Parts of Sumatra and Kalimantan may have rifted from Australia in the Cretaceous and carried an angiosperm flora north. Other terranes, now dispersed in South-East Asia and in the Pacific were, at various times in the Cenozoic, part of the Australian continent. Faunal and floral mobilism to Fiji via the Solomons and Vanuatu was probably not difficult up to the late Miocene.

scholarly journals Crustal movement and strain distribution in East Asia revealed by GPS observations

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Ming Hao ◽  
Yuhang Li ◽  
Wenquan Zhuang
Keyword(s):  
East Asia ◽  
Crustal Deformation ◽  
North China ◽  
Mainland China ◽  
Pacific Plate ◽  
Indian Plate ◽  
Stress Axis ◽  
The Pacific ◽  
Ryukyu Arc ◽  
Gps Observations

AbstractEast Asia is bounded by the Indian plate to the southwest and the Pacific and Philippine plates to the east, and has undergone complex tectonic evolution since ~55 Ma. In this study, we collect and process three sources of GPS datasets, including GPS observations, GPS positioning time series, and published GPS velocities, to derive unified velocity and strain rate fields for East Asia. We observed southward movement and arc-parallel extension along the Ryukyu Arc and propose that the maximum principal stress axis (striking NEE) in North China could be mainly induced by westward subduction of the Pacific plate and the southward movement of the Ryukyu Arc. The large EW-trending sinistral shear zone that bounds North China has been created by eastward movement of South China to the south and westward subduction of the Pacific plate to the north. GPS velocity profiles and strain rates also demonstrate that crustal deformation in mainland China is controlled by northeastward collision of the Indian plate into Eurasia and westward subduction of the Pacific and Philippine Sea plates beneath Eurasia. In particular, the India-Eurasia continental collision has the most extensive impact, which can reach as far as the southern Lake Baikal. The viscous behavior of the subducting Pacific slab also drives interseismic deformation of North China. The crustal deformation caused by Philippine oceanic subduction is small and is limited to the region between the southeast coast of mainland China and Taiwan island. However, the principal compressional strain around eastern Taiwan is the largest in the region.

Relative Timing of the Eocene Global Reorganization of Plate Motions: New Results for Pacific Plate Hotspot Tracks

2021 ◽  
Author(s):  
Kevin Gaastra ◽  
Richard Gordon
Keyword(s):  
Pacific Plate ◽  
Western Pacific ◽  
Plate Motion ◽  
Inversion Method ◽  
Plate Boundaries ◽  
Plate Motions ◽  
The Pacific ◽  
Significant Difference ◽  
Deep Earth ◽  
Earth Dynamics

<p><span> </span><span>To improve</span><span> </span><span>modeling of</span><span> deep-earth dynamics </span><span>it is i</span><span>mportant</span><span> to understand</span><span> changes in the arrangements of plate boundaries, especially trenches accommodating subduction, </span><span>and </span><span>major </span><span>changes</span><span> in tectonic plate motion. </span><span>Here</span><span> we focus on </span><span>the sequence of </span><span>key surface events in </span><span>Eocene </span><span>time that </span><span>likely coincide with changes in </span><span>deep-earth dynamics. In particular, we </span><span>develop </span><span>methods of analysis of seamount locations and age dates using a small number of adjustable parameters (10 per chain)</span><span> on the Pacific plate </span><span>with a focus on the </span><span>timing of the </span><span>Hawaiian-Emperor bend </span><span>relative to the timing of other </span><span>major Eocene tectonic changes</span><span>. </span></p><p><span> </span><span>We find that motion between hotspots differs insignificantly from zero with rates of 2</span><span>±</span><span>4 mm/a (±2</span><span>σ</span><span>) for 0-48 Ma and 26±34 mm/a (±2σ) for 48-80 Ma. Relative to a mean Pacific hotspot reference frame, </span><span>nominal rates of </span><span>motion of the Hawaii, Louisville, and Rurutu hotspots are </span><span>~</span><span>5</span><span> mm/a and </span><span>differ insignificantly from zero</span><span>. We conclude that plumes underlying these Pacific hotspots are more stable in a convecting mantle than previously inferred.</span></p><p><span> We estimate the locations and ages (with uncertainties) of bends in Pacific hotspot chains using a novel inversion method. The location of the ~60° change in trend at the Hawaiian-Emperor bend is well constrained within ~50-80 km (=2σ), but the location of the bends in the Louisville and Rurutu hotspots are more uncertain. If the uncertainty in the location of the bend in the Louisville chain is included, we find no significant difference in age between the bends of different Pacific hotspot chains. The best-fitting assumed-coeval age for the bends is 47.4±1.0 Ma (±2σ), which is indistinguishable from the age of the C21o geomagnetic reversal. The age of the bend is younger than the initiation of subduction in the Western Pacific, but approximately coeval with changes in Pacific and circum-Pacific relative plate motion. Changes to the tectonic system near the age of the bend are not limited to the Pacific basin. The smooth-rough transition flanking the Carlsberg Ridge records a threshold in the decreasing spreading rate between India and Africa, thought to record the onset of the collision of India with Eurasia, and is constrained to be between C21y and C20o (46 Ma and 43 Ma) in age. Nearly simultaneously, South America and Australia began to diverge more rapidly from Antarctica. The Eocene bend in Pacific hotspot chains may be the most evident feature recording a global re-organization of plate motions and mantle circulation possibly caused by the earlier collision of India and Eurasia or initiation of western Pacific subduction.</span></p>

The Double Burden of Malnutrition in East Asia and the Pacific

10.1596/26102 ◽  
2016 ◽  
Author(s):  
Roger Shrimpton ◽  
Nkosinathi Vusizihlobo Mbuya ◽  
Anne Marie Provo
Keyword(s):  
East Asia ◽  
Double Burden ◽  
The Pacific ◽  
Double Burden Of Malnutrition

scholarly journals LC–MS/MS Analysis of Ciguatoxins Revealing the Regional and Species Distinction of Fish in the Tropical Western Pacific

2021 ◽  
Vol 9 (3) ◽  
pp. 299 ◽  
Author(s):  
Naomasa Oshiro ◽  
Takumi Tomikawa ◽  
Kyoko Kuniyoshi ◽  
Akira Ishikawa ◽  
Hajime Toyofuku ◽  
...  
Keyword(s):  
Fish Species ◽  
The Philippines ◽  
Western Pacific ◽  
Tropical Region ◽  
Northern Coast ◽  
Coastal Regions ◽  
Main Island ◽  
Tropical Western Pacific ◽  
The Pacific ◽  
Fish Samples

Ciguatera fish poisoning (CFP) is one of the most frequently reported seafood poisoning diseases. It is endemic to the tropical region and occurs most commonly in the regions around the Pacific Ocean, Indian Ocean, and Caribbean Sea. The principal toxins causing CFP are ciguatoxins (CTXs). In the Pacific region, more than 20 analogs of CTXs have been identified to date. Based on their skeletal structures, they are classified into CTX1B-type and CTX3C-type toxins. We have previously reported species-specific and regional-specific toxin profiles. In this study, the levels and profiles of CTXs in fish present in the tropical western Pacific regions were analyzed using the liquid chromatography–tandem mass spectrometry (LC–MS/MS) technique. Forty-two fish specimens, belonging to the categories of snappers, groupers, Spanish mackerel, and moray eel, were purchased from various places such as Fiji, the Philippines, Thailand, and Taiwan. Only the fish captured from Fijian coastal waters contained detectable amounts of CTXs. The toxin levels in the fish species found along the coastal regions of the Viti Levu Island, the main island in Fiji, and the toxin profiles were significantly different from those of the fish species present in other coastal regions. The toxin levels and profiles varied among the different fish samples collected from different coastal areas. Based on the toxin levels and toxin profiles, the coast was demarcated into three zones. In Zone-1, which covers the northern coast of the main island and the regions of the Malake Island and Korovau, CTXs in fish were below the detection level. In Zone-2, CTX3C-type toxins were present in low levels in the fish. CTX1B-type and CTX3C-type toxins co-occurred in the fish present in Zone-3. The toxin profiles may have reflected the variation in Gambierdiscus spp.

scholarly journals Natural Constraints to Cultural Relativism Example: Ricci’s Pacific-Centered World Maps

2020 ◽  
Vol 73 (3) ◽  
pp. 379-397
Author(s):  
Elmar Holenstein
Keyword(s):  
East Asia ◽  
Canary Islands ◽  
Cultural Relativism ◽  
Central State ◽  
The West ◽  
Gestalt Principles ◽  
Matteo Ricci ◽  
The Pacific ◽  
Made In

AbstractNot everything that is logically possible and technically feasible is also natural, for example, placing China in the exact center of a world map. Such a map would not correspond to the laws of perception.Matteo Ricci, who was the first to create Chinese world maps on which the Americas were depicted, had to choose between two ideals, between a world map that obeys the gestalt principles of perception and a world map with the “Central State” China in its center. The first ideal mattered more to him than the second, although he took the latter into account as well. The result was a Pacific-centered map.Since we live on a sphere, what we perceive to be in the East and in the West depends on our location. It is therefore natural that in East Asia, world maps show America in the East and not – as in Europe – in the West. This was the argument underlying Ricci’s creation of Pacific-centered maps, and not the intention of depicting China as close to the center of the map as possible.It is only in East Asia that Ricci was the first to create Pacific-centered maps. World maps with the Pacific in the midfield were made in Europe before Ricci, motivated by the traditional unidirectional numbering of the meridians (0°–360°) from West to East starting with the Atlantic Insulae Fortunatae (Canary Islands).

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