Discovery of a conical feature in Halmahera waters, Indonesia: traces of a late-stage hydrothermal activity

Geoscience Letters

Research Letter

Astyka Pamumpuni¹  Steven Solikin²  Dyan P. Sobarudin³  Dian Adrianto³  Gabriella Alodia⁴  Idham A. Kurniawan⁵  Mustafa Hanafi⁶  Angga Dwinovantyo⁷  Chris M. Green⁸  Andrew M. McCaig⁸ 

[1] Applied Geology Research Group, Faculty of Earth Sciences and Technology, Institut Teknologi Bandung (ITB), Bandung, Indonesia;Department of Marine Science and Technology, Faculty of Fisheries and Marine Sciences, IPB University, Bogor, Indonesia;Hydro-Oceanographic Centre, Indonesian Navy, Jakarta Utara, Indonesia;Hydrography Research Group, Faculty of Earth Sciences and Technology, Institut Teknologi Bandung (ITB), Bandung, Indonesia;Petrology, Volcanology, and Geochemistry Research Group, Faculty of Earth Sciences and Technology, Institut Teknologi Bandung (ITB), Bandung, Indonesia;Research Centre for Geological Resources, The National Research and Innovation Agency (BRIN), Jakarta Pusat, Indonesia;Research Centre for Oceanography, The National Research and Innovation Agency (BRIN), Jakarta Utara, Indonesia;School of Earth and Environment, University of Leeds, Leeds, UK;

关键词: Multibeam bathymetry;    Magnetic anomaly;    X-ray diffraction (XRD);    Serpentinite seamount;    Hydrothermal activity;    2.5-D magnetic modelling;   

DOI  :  10.1186/s40562-023-00302-w

 received in 2023-04-06, accepted in 2023-10-04,  发布年份 2023

来源: Springer

【 摘 要 】

An expedition to confirm the presence of underwater hazards was carried out in Halmahera waters, Indonesia, to the west of Halmahera Island from August to September 2021. The expedition carried out a multibeam survey, surface-towed magnetic survey, and seafloor sampling. A ~ 615-m-tall conical feature with traces of hydrothermal activity was discovered. The feature is bounded on the southeastern (SE) side by a series of normal faults at the peak, with possible dextral strike-slip faults traced west of the feature. The feature displays the potential presence of volcanic rocks based on the observed contrasting magnetic anomaly signature of down to − 100 nT, which at the magnetic equator corresponds to the presence of highly magnetised material. Four 2.5-D magnetic models were built to test various scenarios on the subsurface structure of the feature, mainly focusing on the presence of volcanic rocks at different epochs and a possible presence of serpentinisation. X-ray diffraction (XRD) of the silt and clay sediments sampled confirms traces of late-stage hydrothermal activity, indicated by a high percentage of quartz (53.87%), followed by calcite (34.56%), kaolinite (6.54%), and illite minerals (5.04%). Non-carbonate materials are yet to be found in the sampled sand and gravel sediments, which mainly consist of shell and coral fragments. The discovery of the conical feature, now termed the Yudo Sagoro Hill, provides new information on the structure and activities on the seafloor of Halmahera waters.

【 授权许可】

CC BY   
© Asia Oceania Geosciences Society (AOGS) 2023

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