| The relationship among tectono-thermal event, its dynamothermal transition, hydrocarbon and other multiple mineral is a hot issue recently in the frontier research field of sedimentary basin dynamics and its effects on resources. Northeastern Ordos basin (NOB) experienced multi-stages tectono-thermal events and the coexisting enrichment of multi-energy resources of Meso-Cenozoic, which is ideal area of researching relationship between dynamothermal transition effecting and the coexisting enrichment of multiple mineral. The paper, on the basis of regional geological structure research, mainly adopts the tectonic thermochronology and hydrocarbon accumulation chronology, systematically establishes chronology sequence of tectonic events and hydrocarbon accumulation events and their compared relationship, analyze the Meso-Cenozoic tectonic thermal events, uplift cooling events and hydrocarbon accumulations effects on dynamothermal transition. The main conclusions are as follows:(1) According to geological structure and geophysical data, the characteristics of structure units zoning and its marginal fault zone is clear. Further combine with sedimentary construction combination and layers unconformity contact, the Meso-Cenozoic sedimentary layers of NOB are divided into Indosinian cycle tectonic sequence (TS1), Yanshanian cycle tectonic sequence (TS2), Himalayan cycle tectonic sequence (TS3), and the corresponding eight tectonic sub-sequences.(2) By means of quantitative tectonic thermochronology analysis, the Meso-Cenozoic tectonic chronology sequence is established. What’s more, the study area mainly experienced two stages tectonic events of roughly240Ma and200Ma in Triassic (the middle and late of Indosinian cycle); two stages tectonic events of roughly135Ma and65Ma in Cretaceous (the middle and late of Yanshanian cycle); one stage tectonic events of roughly20Ma in Neogene (the middle and late of Himalayan cycle).(3) Through different mineral closed temperature comparing and well subsidence history modeling, the Meso-Cenozoic differential uplift rates in dynamothermal transition is revealed: with3.7m/my at the end of the Indosinian; with46.5m/my at the end of the Yan’anian of Early-Middle Jurassic; with8.2m/my in Late Jurassic; with80m/my during late Early Cretaceous to Paleogene; with128m/my since the Neogene.(4) Based on vitrinite reflectance (Ro) and AFTSolve thermal history simulation, the Meso-Cenozoic tectonic thermal evolution history and paleogeothermal parameters of dynamothermal transition is indicated. The key tectono-thermal event occured mainly from135to100Ma of middle Yanshanian with the peak of120Ma, resulting in the maximum palaeogeothermal of hydrocarbon source rock of lower Permian and upper Triassic up to180～110℃, respectively. The late differential uplift caused Permian and its overlying layers of northern section of study area to cool with below110℃in the75Ma of Late Cretaceous. The central souther cooled with below110℃in the20Ma of Neogene.(5) By means of authigenic illite dating and fluid inclusion analysis, the hydrocarbon accumulation chronology sequence is established. The Permian reservoirs of north-central of the study area at least experienced two stages of primary hydrocarbon accumulations with the peak age from170to153Ma and from143to130Ma, respectively. The Triassic reservoirs of souther experienced one stage of primary hydrocarbon accumulations with the peak age from128to112Ma. However, Upper Permian reservoirs of norther of the study area happened secondary hydrocarbon accumulation with the peak age close to30Ma of Paleogene.(6) Based on the above research results, the Meso-Cenozoic tectonic events and hydrocarbon accumulations effects on dynamothermal transition is discussed. The tectono-thermal event of Early Cretaceous (135-120Ma), which is coupling warming events of sedimentary buried and magmatic activity, make the main hydrocarbon source rock of Paleozoic and Mesozoic to large-scale generate hydrocarbon and accumulate. Further more, the late differential uplift, especially two tectonic events of65Ma and20Ma, yield primary hydrocarbon accumulations of Paleozoic to adjust and dissipate, hydrocarbon of Upper Permian to second accumulate.(7) Through placing enrichment of multiple mineral in asymmetric synclinorium and arc tectonic belt located its margin, the spatial distribution of multiple mineral and controlled tectonic critical state is primary analyzed. The tilted arc tectonic belt of synclinorium margin, with dip of layer greater than3-8°, constitute hydrocarbon dissipation and escape area, mineralization area of coal and sandstone type uranium. The tilted arc tectonic belt, with dip of layer greater than2-5°, compose secondary hydrocarbon accumulation area of Upper Permian. The pitching of synclinorium, with dip of layer tending to be horizontal (<1～2°), mainly belong to saving enrichment area of primary hydrocarbon of upper Paleozoic and Mesozoic. |
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