Organic carbon burial is paced by a ∼173-ka obliquity cycle in the middle to high latitudes

Earth's climate system is complex and inherently nonlinear, which can induce some extraneous cycles in paleoclimatic proxies at orbital time scales. The paleoenvironmental consequences of these extraneous cycles are debated owing to their complex origin. Here, we compile high-resolution datasets of total organic carbon (TOC) and stable carbon isotope (delta C-13(org)) datasets to investigate organic carbon burial processes in middle to high latitudes. Our results document a robust cyclicity of similar to 173 thousand years (ka) in both TOC and delta C-13(org). The similar to 173-ka obliquity-related forcing signal was amplified by internal climate feedbacks of the carbon cycle under different geographic and climate conditions, which control a series of sensitive climatic processes. In addition, our new and compiled records from multiple proxies confirm the presence of the obliquity amplitude modulation (AM) cycle during the Mesozoic and Cenozoic and indicate the usefulness of the similar to 173-ka cycle as geochronometer and for paleoclimatic interpretation.

Automated summary

The study demonstrates a cyclical pattern of approximately 173 thousand years in organic carbon burial processes in middle to high latitudes. This signal is amplified by internal climate feedbacks of the carbon cycle under different geographic and climate conditions, controlling a series of sensitive climatic processes. The presence of the obliquity amplitude modulation (AM) cycle during the Mesozoic and Cenozoic is confirmed by new and compiled records from multiple proxies.