Deep-sea hydrogenetic ferromanganese crusts are both potential polymetallic resources and records of long-term environmental changes. For palaeoceanographic studies, it is important to construct a detailed and reliable chronological framework. Here, we report the results of a detailed magnetostratigraphic and rock magnetic study of four hydrogenetic Fe-Mn crusts from the Pacific Ocean (PO-01), South China Sea (SCS-01, SCS-02) and Indian Ocean (IO-01). Two groups of characteristic remanent magnetization directions were defined with nearly antipodal normal and reversed polarities for samples PO-01, SCS-01 and SCS-02, indicating a primary record of the Earth’s magnetic field. The magnetostratigraphic framework, established via correlation with the Geomagnetic Polarity Time Scale 2012, implies growth rates of 4.82 mm/Ma, 4.95 mm/Ma, 4.48 mm/Ma and 11.28 mm/Ma for samples PO-01, SCS-01, SCS-02 and IO-01, respectively. Rock magnetic measurements revealed that the Fe-Mn crust samples from the Pacific Ocean and Indian Ocean were dominated by low coercivity, non-interacting, single-domain (SD) magnetite particles, whereas the South China Sea samples were dominated by SD/pseudo-single-domain (PSD) particles. Multidomain (MD) magnetite may also be present in all samples.
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机译：深海氢锰铁结壳既是潜在的多金属资源，又是长期环境变化的记录。对于古海洋学研究，重要的是构建详细而可靠的时间顺序框架。在此，我们报告了对来自太平洋（PO-01），南海（SCS-01，SCS-02）和印度洋（IO-01）的四个氢铁锰壳的详细地磁和岩石磁学研究的结果。 ）。定义了PO-01，SCS-01和SCS-02样品的两组特征性剩余磁化方向，具有接近反极的法向和相反极性，表明了地球磁场的主要记录。通过与2012年地磁极性时标的相关性建立的地磁地层学框架意味着PO-01，SCS-01，SCS-样品的增长率分别为4.82 4.mm/Ma、4.95 mm / Ma，4.48 mm / Ma和11.28 mm / Ma。分别为02和IO-01。岩石磁学测量表明，来自太平洋和印度洋的Fe-Mn地壳样品以低矫顽力，非相互作用的单畴（SD）磁铁矿颗粒为主，而南中国海样品则以SD /伪石英为主。单域（PSD）粒子。多域（MD）磁铁矿也可能存在于所有样品中。
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