Geological characteristics of the Nankai Trough subduction zone and their tectonic significances

Jie Zhang; Ling Chen; Zihua Cheng; Limei Tang

doi:10.1007/s13131-020-1663-4

Volume 39 Issue 10

Oct. 2020

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Jie Zhang, Ling Chen, Zihua Cheng, Limei Tang. Geological characteristics of the Nankai Trough subduction zone and their tectonic significances[J]. Acta Oceanologica Sinica, 2020, 39(10): 81-95. doi: 10.1007/s13131-020-1663-4

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Jie Zhang, Ling Chen, Zihua Cheng, Limei Tang. Geological characteristics of the Nankai Trough subduction zone and their tectonic significances[J]. Acta Oceanologica Sinica, 2020, 39(10): 81-95. doi: 10.1007/s13131-020-1663-4

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Geological characteristics of the Nankai Trough subduction zone and their tectonic significances

doi: 10.1007/s13131-020-1663-4

Jie Zhang^{1, 3},
Ling Chen^{1, 2
,
,},
Zihua Cheng⁴,
Limei Tang¹

1.
Key Laboratory of Submarine Geosciences, Ministry of Natural Resources/Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou 310012, China
2.
Key Laboratory of Marine Mineral Resources, Guangzhou Marine Geological Survey, Ministry of Natural Resources, Guangzhou 510760, China
3.
Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai 519080, China
4.
Key Laboratory of Ocean and Marginal Sea Geology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China

Funds: The Open Research Fund of the Key Laboratory of Marine Mineral Resources, Guangzhou Marine Geological Survey, MNR under contract No. KLMMR-2017-B-01; the National Program on Global Change and Air–Sea Interaction, SOA under contract No. GASI-GEOGE-01; the Scientific Research Fund of the Second Institute of Oceanography, MNR under contract Nos JG1903 and QNYC1901; the National Natural Science Foundation of China under contract Nos 41706044, 41706041, 41890811 and 91858214; the Open Research Fund of the Key Laboratory of Ocean and Marginal Sea Geology, Chinese Academy of Sciences under contract No. OMG2019-04.

More Information

Corresponding author: E-mail: chenling@sio.org.cn
Received Date: 2020-01-06
Accepted Date: 2020-03-27

Available Online: 2020-12-28

Publish Date: 2020-10-25

Abstract

Abstract

The Nankai Trough subduction zone is a typical subduction system characterized by subduction of multiple geological units of the Philippine Sea Plate (the Kyushu-Palau Ridge, the Shikoku Basin, the Kinan Seamount Chain, and the Izu-Bonin Arc) beneath the Eurasian Plate in the southwest of Japan. This study presents a geophysical and geochemical analysis of the Nankai Trough subduction zone in order to determine the features and subduction effects of each geological unit. The results show that the Nankai Trough is characterized by low-gravity anomalies (–20 mGal to –40 mGal) and high heat flow (60–200 mW/m²) in the middle part and low heat flow (20–80 mW/m²) in the western and eastern parts. The crust of the subducting plate is 5–20 km thick. The mantle composition of the subducting plate is progressively depleted from west to east. Subduction of aseismic ridges (e.g., the Kyushu-Palau Ridge, the Kinan Seamount Chain, and the Zenisu Ridge) is a common process that leads to a series of subduction effects at the Nankai Trough. Firstly, aseismic ridge or seamount chain subduction may deform the overriding plate, resulting in irregular concave topography along the front edge of the accretionary wedge. Secondly, it may have served as a seismic barrier inhibiting rupture propagation in the 1944 M_w 8.1 and 1946 M_w 8.3 earthquakes. In addition, subduction of the Kyushu-Palau Ridge and hot and young Shikoku Basin lithosphere may induce slab melting, resulting in adakitic magmatism and the provision of ore-forming metals for the formation of porphyry copper and gold deposits in the overriding Japan Arc. Based on comparisons of their geophysical and geochemical characteristics, we suggest that, although the Izu-Bonin Arc has already collided with the Japan Arc, the Kyushu-Palau Ridge, which represents a remnant arc of the Izu-Bonin Arc, is still at the subduction stage characterized by a single-vergence system and a topographic boundary with the Japan Arc.
- Nankai Trough,
- subduction zone,
- velocity structure,
- gravity modeling,
- geochemistry,
- petrology,
- slab melting,
- geological effect

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References(87)

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