A 23 Myr magnetostratigraphic time framework for Site 1148, ODP Leg 184 in South China Sea and its geological implications |
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| Institution: | 1. Departamento de Estratigrafía y Paleontología, Universidad de Granada, Avd. De la Fuente Nueva S/N, 18071 Granada, Spain;2. Institute of Geology, University of Hamburg, Bundesstrasse 55, 20146 Hamburg, Germany;1. Academy of Scientific and Innovative Research (AcSIR), CSIR-National Geophysical Research Institute, Uppal Road, Hyderabad 500 007, India;2. CSIR- National Geophysical Research Institute, Uppal Road, Hyderabad 500 007, India |
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| Abstract: | The Ocean Drilling Program (ODP) Leg 184 recovered a continuous sedimentary sequence since Miocene at Site 1148 in the northern South China Sea (SCS), which provided a unique record for better understanding the tectonic, environmental and climatic evolution of the SCS. In this study, we report a detailed paleomagnetic study on 881 discrete samples from the upper 460 m cores of Hole 1148A through stepwise alternating field demagnetization (AF) or thermal demagnetization (TD). Rock magnetic results from isothermal remanent magnetization (IRM) acquisition, temperature dependence magnetic susceptibility (κ-T) and hysteresis loop parameters of representative samples indicate that the main magnetic mineral is low coercivity pseudo-single domain magnetite. The characteristic remanent magnetization (ChRM) with moderate downward or upward inclinations was identified after removing a low-stability drilling-induced remanence with steep downward inclinations. A new 23 Myr magnetostratigraphic time framework was established by correlating the magnetic polarity sequence to the Geomagnetic Polarity Time Scale 2012 (GPTS 2012; Ogg, 2012) in combination with biostratigraphic data. The mean sediment accumulation rates for lithostratigraphic Units V and IV, Unit III and lower Unit II, upper Unit II, Unit IB and Unit IA are calculated as ～20.8 m/Myr, ～15–17 m/Myr, 24.18 m/Myr, 17.07 m/Myr and 49.01 m/Myr, respectively. |
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| Keywords: | Magnetostratigraphy ODP Leg 184 Site 1148 South China Sea |
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