Thermal Structure Types and Stages of Zijinshan Rock Body and Their Influence upon Several Energy Resources and Minerals in Eastern Ordos Basin
紫金山岩体的热力构造类型、期次及其对鄂尔多斯盆地东缘多种能源矿产的影响作用

Zijinshan complex in eastern Ordos basin, an alkaline rock body formed in several stages, can be divided into six phases from the outer part to the core. The rock body morphologically forms a normal dome type thermal structure. Monzonite, aegirine-augite syenite, malignite and nepheline syenite belong to the intermediate-deep intrusion type thermal structure, whereas phonolite/phonolitic volcanic breccia and trachyte/trachytic volcanic breccia are of the superficial/shallow volcanic eruption type. Since the beginning of Triassic period, there have occurred three thermal activities in Zijinshan area. The intermediate-deep intrusion from Late Jurassic to Early Cretaceous accelerated coal metamorphism which resulted in secondary hydrocarbon production. It also accelerated the maturity of Upper Paleozoic hydrocarbon source rock (coal and dark mudstone), and led to volcanic piercing closure resulting from upward magmatic intrusion, which finally became an oil/gas-bearing structure.