Eccentricity-paced geomagnetic field and monsoon rainfall variations over the last 870 kyr

Abstract

Whether there are links between geomagnetic field and Earth’s orbital parameters remains unclear. Synchronous reconstructions of parallel long-term quantitative geomagnetic field and climate change records are rare. Here, we present 10 Be-derived changes of both geomagnetic field and Asian monsoon (AM) rainfall over the last 870 kyr from the Xifeng loess–paleosol sequence on the central Chinese Loess Plateau. The  10 Be GM flux (a proxy for geomagnetic field-induced 10 Be production rate) reveals 13 consecutive geomagnetic excursions in the Brunhes chron, which are synchronized with the global records, providing key time markers for Chinese loess–paleosol sequences. The  10 Be-derived rainfall exhibits distinct ~100 kyr glacial–interglacial cycles, and superimposed precessional (~23 kyr) cycles that match with those in Chinese speleothem δ 18 O record. We find that changes in the geomagnetic field and AM rainfall share a common ~100 kyr cyclicity, implying a likely eccentricity modulation of both the geomagnetic field and climate.