Environmental Magnetism Study On Huoshiling Formation Of The SK? In The Songliao Basin

Nowadays,global warming is getting worse.To grasp the changing trends of the future climate,it is necessary to analyze the process of greenhouse climate change in geological history and the impact of the warm climate on the Earth's life system.The Cretaceous is characterized by a typical greenhouse climate.Therefore,it is important to study the Cretaceous climate change process and the impact of the greenhouse climate on the Earth system.The Songliao Basin is located in northeast China and is one of the largest continental basins during the Cretaceous period.The formation is continuous and has a large thickness,which provides a good geological record for studying the Cretaceous climate change.The International Continental Scientific Drilling?ICDP?program approved two phases of the“Songke 1 Well”and“Songke 2Well”projects."Songke 2 Well"is the deepest scientific drilling since the establishment of the ICDP program.It is the world's first scientific drilling well to drill through the Cretaceous continental strata.The purpose of the scientific drilling of the Songke 2 well is to obtain continuous high-resolution terrestrial geological records and understand the process of climate change in the Cretaceous greenhouse.This paper selects the research methods of environmental magnetism and rock magnetism,and analyzes the changes of the type,particle size and content of magnetic minerals in rocks,and then explains the changes of the Early Cretaceous climate and the geological tectonic movements in the basin.Through analysis,the components of Flint Ridge can be divided into three sections:A,B and C.The main ingredients of section A is,with the lowest magnetic mineral content and the coarsest grain size,mainly soft magnetic minerals with low coercivity;The main ingredients of section B is andesite,indicating the volcanic eruption event,has the highest content of magnetic minerals and the finest grain size.The types of magnetic minerals vary greatly,mainly magnetite,and high-coercivity magnetic minerals;the magnetic mineral content and particle size of the section C are between section A and B,and the magnetic mineral types vary greatly,which may contain Hematite,magnetite,etc.Combined with previous studies,it can be inferred that the sedimentary phase of section C is alluvial fan facies.At this time,coarse-grained minerals are deposited,and it is known that the source area is closer to the basin,and it is inferred that the source may come from the northern and northeastern uplifts.At this time,the lake has not yet formed,and it is inferred that the C section is a cold and arid climate.The B-segment has the highest content of magnetic minerals.At this time,the volcanic eruption is strong,releasing a large amount of CO₂ and water vapor,and the basin collapse activity is strong.When the A section is deposited,the climate is warm and humid.At this time,the lake surface is relatively high,and the reduction of diagenesis results in a lower magnetic susceptibility value.The difference in magnetic parameters between the A and C section is mainly related to climate change and the uplifting movement of the basin.During the deposition of the A section,the basin depression developed,and the sediment source was also different from the C section.It is concluded that the sediments of the section A are not only from the northeast,but also from the distant source areas.