Phanerozoic magmatism and ocean-continent framework of northeastern China and their relationship with climate change

Through the Phanerozoic Eon, Earth's climate has varied between greenhouse and icehouse states. On multimillion-year time scales, the paleoclimate change has been considered to be the coupled result of carbon dioxide sources and sinks, but it is still unknown about their degree of contribution to transitions between these background climate states. According to global statistical analysis, variations in continental volcanic arc emissions and tropics arc-continent collisions are hypothesized to account for the Phanerozoic climate change, and different models emphasize a first order role of carbon sources and carbon sinks, respectively. In order to test the above models and better understand the transition mechanism and evolutionary details of paleoclimate, this paper systematically summarizes the temporal-spatial distribution and tectonic settings of Phanerozoic magmatism-skarn deposits, as well as the age, scale and paleogeographic position of arc-continent collisional sutures within Northeast (NE) China. Data statistics and chart comparison of NE China show strong correlations among the magmatic and skarn metallogenic peaks, the temporal-spatial variations of arc-continent collisional sutures, the extent of glaciation, and the atmospheric CO2 levels, implying a genetic relationship between Phanerozoic tectono-magmatic processes of NE China with global paleoclimate change. Integration with the pre-existing worldwide results, we propose the following tendentious views: 1) the extent of volcanic-metamorphic outgassing during oceanic-continental subduction determines CO2 emissions, while the scale of arc-continent collisional sutures within the tropics controls global weatherability and thus determines CO, consumption. Both of them are closely linked over geological history, and together control the Phanerozoic paleoclimate change; 2) global eruptions of continental arc magmatism do not necessarily result in a greenhouse climate. In the absence of adequate skarn-induced metamorphic decarburization, the CO2 emission flux of continental arcs is not significantly different from that of island arcs, mid-ocean ridges and intraplates; 3) SO2 is a short-term effect gas, and both theory and case studies suggest that explosive volcanisms are difficult to induce the formation of the Great Ice Age. Volcanic eruptions should still be contributing to the warming of the earth rather than cooling in long-term climate.