Evolution of the Late Cretaceous Dadaepo Basin, SE Korea, in response to oblique subduction of the proto-Pacific (Izanagi/Kula) or Pacific plate

2016 ◽  
Vol 39 ◽  
pp. 145-164 ◽  
Author(s):  
Hyeongseong Cho ◽  
Moon Son ◽  
Youngbeom Cheon ◽  
Young Kwan Sohn ◽  
Jong-Sun Kim ◽  
...  
Keyword(s):  
Late Cretaceous ◽  
Pacific Plate ◽  
Oblique Subduction

Late Cretaceous granitoids of the Sikhote–Alin orogenic belt, southeastern Russia: implications for the Mesozoic geodynamic history of the eastern Asian continental margin

2021 ◽  
pp. jgs2021-109
Author(s):  
Igor V. Kemkin ◽  
Andrei V. Grebennikov ◽  
Xing-Hua Ma ◽  
Ke-Ke Sun
Keyword(s):  
Late Cretaceous ◽  
Pacific Plate ◽  
Orogenic Belt ◽  
Sikhote Alin ◽  
Asian Continent ◽  
Content Type ◽  
Eastern Margin ◽  
Continental Plate ◽  
Supplementary Material ◽  
Cretaceous Magmatism

We present new U–Pb age data for granitoids in the Central Sikhote–Alin orogenic belt in SE Russia, which refute the established opinion about the absence of the Late Cretaceous magmatism at the eastern margin of the Paleo-Asian continent. It was previously thought that a period of magmatic quiescence occurred from 88 to 50 Ma, related to subduction of the Paleo-Pacific Plate under the eastern margin of the Paleo-Asian continent, although this is inconsistent with evidence from the Sikhote–Alin, Sakhalin, and Japan regions. Three suites of plutonic rocks with different ages were identified in this study. The first suite has ages of 105–92 Ma and formed in a syn-orogenic setting. The second (86–83 Ma) and third (ca. 73 Ma) suites formed during the post-orogenic stage of the Sikhote–Alin orogenic belt. The second and third suites were coeval with Late Cretaceous granitoids that formed in a suprasubduction continental arc known as the Eastern Sikhote–Alin volcanic–plutonic belt (ESAVPB). However, the studied rocks are located far inland from the ESAVPB. The ages of the studied granitoids coincide with the timing of a change in the angle of convergence between the Paleo-Pacific Plate and eastern margin of the Paleo-Asian continent. This change in motion of the oceanic plate with respect to the continental plate was probably caused by a rupture in the subducted slab (i.e., a slab tear), followed by asthenospheric upwelling and partial melting of the overlying crust, which ultimately generated post-orogenic intrusive magmatism.Supplementary material:https://doi.org/10.6084/m9.figshare.c.5738616

Late cretaceous pelagic sediments, volcanic ASH and biotas from near the Louisville hotspot, Pacific Plate, paleolatitude ∼42°S

1989 ◽  
Vol 71 (3-4) ◽  
pp. 281-299 ◽  
Author(s):  
Peter F. Ballance ◽  
John A. Barron ◽  
Charles D. Blome ◽  
David Bukry ◽  
Peter A. Cawood ◽  
...  
Keyword(s):  
Late Cretaceous ◽  
Volcanic Ash ◽  
Pacific Plate

The Queen Charlotte Islands refraction project. Part II. Structural model for transition from Pacific plate to North American plate

1989 ◽  
Vol 26 (9) ◽  
pp. 1713-1725 ◽  
Author(s):  
D. J. Mackie ◽  
R. M. Clowes ◽  
S. A. Dehler ◽  
R. M. Ellis ◽  
P. Morel-À-l'Huissier
Keyword(s):  
Fault Zone ◽  
North American ◽  
Velocity Structure ◽  
Pacific Plate ◽  
North American Plate ◽  
Lithospheric Structure ◽  
Gravity Modelling ◽  
Oblique Subduction ◽  
Queen Charlotte Islands ◽  
Thin Crust

The oceanic-continental boundary west of the Queen Charlotte Islands is marked by the active Queen Charlotte Fault Zone. Motion along the fault is predominantly dextral strike slip, but relative plate motion and other studies indicate that a component of convergence between the oceanic Pacific plate and the continental North American plate presently exists. This convergence could be manifest through different types of deformation: oblique subduction, crustal thickening, or lateral distortion of the plates. In 1983, a 330 km offshore–onshore seismic refraction profile extending from the deep ocean across the islands to the mainland of British Columbia was recorded to investigate (i) structure of the fault zone and associated oceanic–continental boundary and (ii) lithospheric structure beneath the islands and Hecate Strait to define the regional transition from Pacific plate to North American plate and thus the nature of the convergence. Two-dimensional ray tracing and synthetic seismogram modelling of many record sections enabled the derivation of a composite velocity structural section along the profile. The structural section also was tested with two-dimensional gravity modelling. Part I of the study addressed the structure of the fault zone; part II addresses lithospheric structure extending eastward to the mainland.The derived velocity structure has some important and well-constrained features: (i) anomalously low crustal velocities (5.3 km/s with a 0.2 km/s per km gradient) underlain by a steep, 19 °eastward-dipping boundary above the mantle in the terrace region west of the main fault; (ii) a thin crust of 21–27 km beneath the Queen Charlotte Islands; and (iii) a gentle 4 °eastward dip of the Moho below Hecate Strait as crustal thickness increases from 27 km to 32 km. The gravity modelling requires that mantle material extend upwards to a depth of about 30 km below the mainland and indicates that an underlying subducted slab, if it exists, extends eastward no farther than the mainland.Unfortunately, the velocity structure delineated by this study could not unambiguously determine the mode of deformation, because the lowermost crustal block beneath Queen Charlotte Islands and Hecate Strait can be interpreted as subducted oceanic crust or middle to lower continental crust. Thus, two different tectonic models for the transition from Pacific plate to North American plate are discussed: in one, oblique subduction is the principal characteristic; in the other, oceanic lithosphere juxtaposed against continental lithosphere across a narrow boundary zone along which only transcurrent motion occurs is the dominant feature. Based on the thin crust beneath the Queen Charlotte Islands, the lack of a wide zone of deformation along the plate boundary region, and other geological and geophysical characteristics, oblique subduction is the more plausible model.

Mesozoic large magmatic events and mineralization in SE China: oblique subduction of the Pacific plate

2010 ◽  
Vol 53 (5-6) ◽  
pp. 704-726 ◽  
Author(s):  
Fang-Yue Wang ◽  
Ming-Xing Ling ◽  
Xing Ding ◽  
Yan-Hua Hu ◽  
Ji-Bin Zhou ◽  
...  
Keyword(s):  
Pacific Plate ◽  
Oblique Subduction ◽  
The Pacific ◽  
Se China
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