Research paperSill-related seafloor domes in the Zhongjiannan Basin, western South China Sea
Introduction
Analysis of seafloor geomorphologic features can provide a hint for understanding subsurface structures and processes developed in many sedimentary basins. This is the case of seafloor domes related to igneous sills emplaced at depth along magma-rich margins (Hansen and Cartwright, 2006; Sánchez-Guillamón et al., 2018a, 2018b). These magmatic intrusions have important implications for hydrocarbon exploration (Hansen et al., 2008; Holford et al., 2012), metal mineralization (Nelson, 2000), global climate change (Svensen et al., 2004), and basin-scale processes (Song et al., 2017). Examples of sill-dome structures have been well described in the southern Australian margin (Jackson et al., 2013), the Norwegian Sea (Planke et al., 2005; Omosanya et al., 2017), the eastern central Atlantic (Medialdea et al., 2017; Sánchez-Guillamón et al., 2018a, 2018b) and other worldwide magma-rich margins. Igneous intrusions are also widely distributed among the South China Sea (SCS) basins and continental slopes (Yan et al., 2006; Song et al., 2017; Wang et al., 2019). For instance, sill-fed volcanic mounds and hydrothermal vents have been observed in the Pearl River Mouth Basin (Sun et al., 2014; Zhao et al., 2014) and in the Qiongdongnan Basin (Wang et al., 2019) respectively.
Igneous intrusions may take various forms when emplaced in sedimentary layers (Lee et al., 2006), among which sills are the most common ones. Emplacement of igneous sills within sediments can result in the development of forced folds (Hansen and Cartwright, 2006; Jackson et al., 2013; Sun et al., 2014; Omosanya et al., 2017; Zhang et al., 2017) and/or formation of hydrothermal vent complexes (Jamtveit et al., 2004; Svensen et al., 2004; Planke et al., 2005; Hansen et al., 2008; Magee et al., 2015; Medialdea et al., 2017; Omosanya et al., 2018; Wang et al., 2019). These sill-related forced folds typically manifest as domes on the seafloor (Sánchez-Guillamón et al., 2018a, Sánchez-Guillamón et al., 2018b), and some may be overlain by younger strata, which will date the timing of intrusion event (Trude et al., 2003; Hansen and Cartwright, 2006; Jackson et al., 2013).
Compared to the extensive studies carried out on other geomorphologic features pockmarks, gullies and mud volcanoes in the adjacent northwestern Zhongjiannan Basin (ZJNB, Bai et al., 2014; Chen et al., 2015a, 2015b; Geng et al., 2017; Chen et al., 2018), forced folds or domes in the northeastern basin are barely understood. Domes, as well as volcanic mounds and seamounts, can delineate in detail subsurface magmatic activity, which will help to understand volcanism effects in the ZJNB. Here, we focus on the study of the distribution and morphology of these newly recognized domes and their relationship with massive igneous intrusions at different depths within the basin. With this aim, accurate renderings of these sill-folds-dome structures are provided in the ZJNB, western SCS.
Section snippets
Geological settings
The ZJNB is a Cenozoic sedimentary basin located in the western SCS continental margin. The NNE-strike ZJNB covers an area over 113,900 km2, at water depths ranging from 50 m to 3800 m (Fig. 1). As shown in Fig. 1b, the ZJNB is dominated by tensional normal faults, accompanying by secondary faults with similar strikes arranged in echelon fashion (Qiu et al., 2005). These faults control the development of the basin's uplift-depression frameworks and divide the ZJNB into six secondary structural
Data and methods
Several multichannel seismic reflection sections, together with multibeam bathymetric data acquired by the Guangzhou Marine Geological Survey are used to analyze the distributions, the characteristics and the subsurface structures of domes and igneous sills in the northeastern ZJNB. The multichannel seismic reflection data were acquired in 2001 using a 1587.5 m long streamer with 128 channels (group interval 12.5 m). The seismic source volume is 0.0492 m3 And the shot interval is 25 m. The main
Results
As shown in Fig. 2b, most of the study area lies in a depression with low slope gradients (average value of 0.26°) surrounded by different reliefs (seamounts, cones, mounds, ridges, etc). In the central depression, the second obvious features are the large seamounts and volcanic mounds in the western part of the study area. Forty-two seafloor domes with gentler slopes are found in the study area, which show subcircular, elongate or irregular in plan view (Fig. 2). These domes are distributed in
Domes, igneous sills and forced folds
In the study area, forty-two domes have been identified by the multibeam bathymetric and multichannel seismic reflection data (Fig. 1, Fig. 2). All the domes' formation and development in the study area are closely related to igneous intrusions in the deep strata. The seafloor domal structures correlate well with the underlying igneous intrusions (e.g. Jackson et al., 2013; Sun et al., 2014). As shown in Fig. 13, the igneous intrusions act as a major heat source in the sedimentary basin. Due to
Conclusions
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A total of forty-two domes and their related subsurface structures have been identified by the multibeam bathymetric and multichannel seismic reflection data in the northeastern ZJNB, western SCS. They mainly cluster in the edge of the central depression, around the volcanic mounds or large seamounts, at water depths between 2312 m and 2870 m. These domes generally show circular to elongate or irregular in plan view, with perimeters between 3 km and 26 km and vertical reliefs no larger than
CRediT authorship contribution statement
Minghui Geng: Conceptualization, Methodology, Writing - review & editing, Investigation. Haibin Song: Investigation, Writing - original draft. Yongxian Guan: Data curation, Visualization. Jiangxin Chen: Writing - review & editing. Ruwei Zhang: Software, Validation. Baojin Zhang: Investigation. Xudong Zhang: Investigation.
Declaration of competing interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Acknowledgements
We thank the Guangzhou Marine Geological Survey for the permission of releasing these data for scientific research. We are grateful to thank Dr. Omosanya, Dr. Schofield and another anonymous reviewer for their constructive comments. This work is supported by the National Key R&D Program of China [grant number 2018YFC0310000]; the Key Special Project for Introduced Talents Team of Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou) [grant number GML2019ZD0207]; the National
References (55)
- et al.
Morphologies, classification and genesis of pockmarks, mud volcanoes and associated fluid escape features in the northern Zhongjiannan Basin, South China Sea
Deep-Sea Res. Pt. II
(2015) - et al.
Geological and oceanographic controls on seabed fluid escape structures in the northern Zhongjiannan Basin, South China Sea
J. Asian Earth Sci.
(2018) - et al.
Geological development of the central and south Vietnamese margin: implications for the establishment of the south China Sea, indochinese escape tectonics and cenozoic volcanism
Tectonophysics
(2009) - et al.
Geological evolution, regional perspectives and hydrocarbon potential of the northwest Phu Khanh Basin, offshore Central Vietnam
Mar. Petrol. Geol.
(2009) - et al.
The three-dimensional geometry and growth of forced folds above saucer-shaped igneous sills
J. Struct. Geol.
(2006) - et al.
Miocene igneous activity in the northern subbasin, offshore Senegal, NW africa
Mar. Petrol. Geol.
(2008) - et al.
Igneous complexes in the eastern northern south Yellow Sea Basin and their implications for hydrocarbon systems
Mar. Petrol. Geol.
(2006) - et al.
Volcano growth mechanisms and the role of sub-volcanic intrusions: insights from 2D seismic reflection data
Earth Planet Sci. Lett.
(2013) - et al.
Three-dimensional (3-D) seismic imaging of conduits and radial faults associated with hydrothermal vent complexes (Vøring Basin, Offshore Norway)
Mar. Geol.
(2018) - et al.
Forced folding and complex overburden deformation associated with magmatic intrusion in the Vøring Basin, offshore Norway
Tectonophysics
(2017)
Saucer-shaped intrusions: occurrences, emplacement and implications
Earth Planet Sci. Lett.
The shallow depth emplacement of mafic intrusions on a magma-poor rifted margin: an example from the Bight Basin, Southern Australia
Mar. Petrol. Geol.
Morphology and shallow structure of seafloor mounds in the canary basin (eastern central atlantic ocean)
Geomorphology
Characteristics of the surface heat flow in the South China Sea
J. Asian Earth Sci.
Fault-sill interaction: implications for magma routing in the vøring basin, Norwegian North Sea
J. Struct. Geol.
Seismic Reflection Data Reveal the Characteristics of Magmatic Activity in the South China Sea (In Chinese)
Magmatism in the evolution of the south China Sea: geophysical characterization
Mar. Geol.
Neogene igneous intrusions in the northern South China Sea: evidence from high-resolution three dimensional seismic data
Mar. Petrol. Geol.
The morphologies and genesis of mega-pockmarks near the Xisha Uplift, South China Sea
Mar. Petrol. Geol.
Seismic characteristics and evolution of post-rift igneous complexes and hydrothermal vents in the Lingshui sag (Qiongdongnan basin), northwestern South China Sea
Mar. Geol.
The temporal and spatial distribution of volcanism in the South China Sea region
J. Asian Earth Sci.
Submarine volcanic mounds in the Pearl River Mouth Basin, northern south China Sea
Mar. Geol.
Basin-controlling faults and formation mechanism of the Cenozoic basin groups in the western South China Sea (in Chinese)
Mar. Geol. Quat. Geol.
Structural characteristics and genesis of pockmarks in the northwest of the South China Sea derived from reflective seismic and multibeam data (in Chinese)
Chin. J. Geophys.
Distribution characteristics and geological implications of pockmarks and mud volcanoes in the northern and western continental margin of the South China Sea (in Chinese)
Chin. J. Geophys.
Analysis of structural styles of Zhongjiannan Basin in the south China Sea (in Chinese)
Mar. Geol. Quat. Geol.
Analysis of local tectonic characters of Zhongjiannan basin in South China Sea (in Chinese)
Mar. Geol. Quat. Geol.
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2024, Bulletin of the Geological Society of America