Yongtao Fu, Guoliang Zhang, Wanyin Wang, An Yang, Tao He, Zhangguo Zhou, Xiao Han. Identification of the Caroline Plate Boundary: Constraints from Magnetic Anomaly[J]. Acta Oceanologica Sinica. doi: 10.1007/s13131-023-2272-9
Citation:
Yongtao Fu, Guoliang Zhang, Wanyin Wang, An Yang, Tao He, Zhangguo Zhou, Xiao Han. Identification of the Caroline Plate Boundary: Constraints from Magnetic Anomaly[J]. Acta Oceanologica Sinica. doi: 10.1007/s13131-023-2272-9
Yongtao Fu, Guoliang Zhang, Wanyin Wang, An Yang, Tao He, Zhangguo Zhou, Xiao Han. Identification of the Caroline Plate Boundary: Constraints from Magnetic Anomaly[J]. Acta Oceanologica Sinica. doi: 10.1007/s13131-023-2272-9
Citation:
Yongtao Fu, Guoliang Zhang, Wanyin Wang, An Yang, Tao He, Zhangguo Zhou, Xiao Han. Identification of the Caroline Plate Boundary: Constraints from Magnetic Anomaly[J]. Acta Oceanologica Sinica. doi: 10.1007/s13131-023-2272-9
Key Laboratory of Ocean Observation and Forecasting, Key Laboratory of Marine Geology and Environment, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China
2.
National Engineering Research Center for Offshore Oil and Gas Exploration, Beijing 100028, China
3.
Laboratory for Marine Geology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China
4.
Center of Deep Sea Research, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China
5.
Institute of Gravity and Magnetic Technology, College of Geology Engineering and Geomatics, Key Laboratory of Western Chinaʹs Mineral Resources and Geological Engineering, Ministry of Education, Changʹan University, Xiʹan 710054, China
6.
University of Chinese Academy of Sciences, Beijing 100049, China
Funds:
‘Open Fund of the Key Laboratory of Marine Geology and Environment’ from Chinese Academy of Sciences, under contract No. MGE2022KG11.
The Caroline Plate is located among the Pacific Plate, the Philippine Sea Plate, and the India Australia Plate, and plays a key role in controlling the spreading direction of the Philippine Sea Plate. The Caroline Submarine Plateau (or Caroline Ridge) and the Eauripik Rise on the south formed a remarkable T-shaped large igneous rock province, which covered the northern boundary between the Caroline Plate and the Pacific Plate. However, relationship between these tectonic units and magma evolution remains unclear. Based on magnetic data from the Earth Magnetic Anomaly Grid (2-arc-minute resolution) (V2), the normalized vertical derivative of the total horizontal derivative (NVDR-THDR) technique was used to study the boundary of the Caroline Plate. Results show that the northern boundary is a transform fault that runs 1400 km long in approximately 28 km wide along the N8° in E-W direction. The eastern boundary is an NNW-SSE trending fault zone and subduction zone with a width of tens to hundreds of kilometers; and the north of N4° is a fracture zone of dense faults. The southeastern boundary may be the Lyra Trough. The area between the southwestern part of the Caroline Plate and the Ayu Trough is occupied by a wide shear zone up to 100 km wide in nearly S-N trending in general. The Eauripik transform fault (ETF) in the center of the Caroline Plate and the fault zones in the east and west basins are mostly semi-parallel sinistral NNW-SSE–trending faults, which together with the eastern boundary Mussau Trench sinistral fault, the northern Caroline transform fault, and the southern shear zone of the western boundary, indicates the sinistral characteristics of the Caroline Plate. The Caroline hotspot erupted in the Pacific Plate near the Caroline transform fault and formed the West Caroline Ridge, and then joined with the Caroline transform fault at the N8°. A large amount of magma erupted along the Caroline transform fault, by which the East Caroline Ridge was formed. At the same time, a large amount of magma developed southward via the eastern branch of the ETF, forming the northern segment of the Eauripik Rise. Therefore, the magmatic activity of the T-shaped large igneous province is obviously related to the fault structure of the boundary faults between the Caroline Plate and Pacific Plate, and the active faults within the Caroline Plate.
Figure 1. a. Submarine topography and geological units in the research area. The topography data are from GEBCO Compilation Group (2022) GEBCO_2022 Grid. The magnetic lineation data in the Caroline Basin are from Gaina and Müller (2007). The magnetic lineation in the Pacific Plate is from Zhu et al. (2022). The white dots represent islands in the Federated States of Micronesia. The white dotted line is the presumed boundary between the Caroline Plate and the Pacific Plate. The green dashed line indicates the modeled track of the Caroline hot spot since 25 Ma, based on Wu et al. (2016). AT: Ayu Trough; BS: Bismark Sea; CHS: Caroline Hot Spot; CHST: Caroline Hot Spot Track; CI: Caroline Islands; CP: Caroline Plate; ECB: East Caroline Basin; ECR: East Caroline Ridge; ER: Eauripik Rise; FaiA: Fais Atoll; FarA: Faraulep Atoll; I-AP: Indo-Australian Plate; KT: Kiilsgaard Trough; LT: Lyra Trough; ManT: Manus Trench; MR: Mapia Ridge; MarT: Mariana Trench; MHS: Manus Hot Spot; MusT: Mussau Trench: NGT: New Guinea Trench; PP: Pacific Plate; PT: Palau Trench; PSP: Philippine Sea Plate; ST: Sorol Trough: UA: Ulithi Atoll; WCB: West Caroline Basin; WCR(N): West Caroline Ridge (North); WCR(S): West Caroline Ridge (South); WCT: West Caroline Trough; YT: Yap Trench. The red star indicates the Site CJ09-82 (Yan et al., 2022). The green triangles are dredge hauls by RV Kexue from the Institute of Oceanology, Chinese Academy of Sciences (Zhang et al., 2020). The blue triangles are dredge hauls by the RV “Vema” (hauls D19, D20, and D21) (Fornari et al., 1979). DSDP57 and DSDP62 are from Ian Ridley et al. (1974) and Den et al. (1971), respectively. b. The free air gravity anomaly (satellite altimetry gravity anomaly) mapof the research area. Data are from Sandwell et al. (2021). The names of geological units are the same as Fig.1a.
Figure 2. ΔT magnetic anomaly map of the research area. The geological unit names are the same as Fig.1a.
Figure 3. The RTP magnetic anomaly in the research area. The geological unit names are the same as Fig.1a.
Figure 4. The distribution of the Caroline Plate fault. The yellow-and-green lines are NVDR-THDR of RTP magnetic anomaly. The purple line in the upper right corner is the magnetic lineation recognized by Zhu et al. (2022). CTF: Caroline Transform Fault; DZ: Disruptured zone in the northern section of the eastern boundary of the Caroline Plate; ECBF: NNW trending fault in the East Caroline Basin; LT: Lyra Trough; MusT: Mussau Trench; ETF: Eauripik Transform Fault; NERF: northern Eauripik Rise fault; PPF: NW trending fault zone in the Pacific Plate; STF: Sorol Trough Fault zone; SWSZ: Southwest shear zone; WCBF: Fault zone within the West Caroline Basin.
Figure 5. Schematic diagram showing the sinistral movement of the Caroline Plate, the distribution of faults in the research area, and the locations of the West Caroline Ridge, East Caroline Ridge, and Eauripik Rise. The geological unit names are the same as in Fig. 1a, and the fault zone names are the same as in Fig. 4. The light-brown area is the enclosure of 3000 m isobath, which is also the T-shaped large igneous province.
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