Polymetallic nodule mineralization in the Pigafeta Basin, West Pacific responses to the Antarctic ice-sheet evolution

Abstract

Abstract We found polymetallic nodules wide spread in the Pigafeta Basin, West Pacific. It turns out to be influenced by the Antarctic Bottom Current, which forms around the Antarctic ice-sheet through surface-water freezing. Thus, we propose the polymetallic nodule mineralization is coupling with the Antarctic ice-sheet evolution. In order to clarify the coupling relationship, we here carry out chronology and geochemistry analysis. The polymetallic nodules consist of four layers and three sedimentary discontinuities. The chronology results demonstrate that nucleation age is ~ 34 Ma, and three sedimentary discontinuities are > 25 Ma, 14.2~16.9Ma and 3.7 ~ 3.4 Ma. Coincidentally, the polymetallic nodules stopped growing during global warming and accreted when glaciation occurred in the Antarctic. In addition, there are coupling effects between the Antarctic ice-sheet parameter (volume and standard deviation) and geochemical indexes of the polymetallic nodules (MgO/CaO and Mn/Fe). These coupling effects indicate that the polymetallic nodule mineralization in the Pigafeta Basin respond to the Antarctic ice-sheet evolution.