The development of the
terrestrial theory on petroleum generation and its breakthrough in exploration have extricated China
from its oil-poor predicament. From 1930s to 1940s, a great number of Chinese scientists put forward one after another a concept on oil
generation from
terrestrial deposits. In the late 1950s, Prof. Hou Defeng stated that inland deep-lake basins and permanent depressions were advantageous to oil generation. In his long-term geological studies, Prof. Hou Defeng had paid great attentions to the controlling effects of paleoclimate on material distribution, to the close combination of palaeontology, sedimentology and geochemistry,and to the influence of paleoclimatic cycles over the formation and distribution of oil and gas reserviors. The concept of “inland humid depression”, one of the major ideas of the theory on terrestrial petroleum generation, takes the evolution of sedimentary organic matter as a fundamental condition for oil-gas formation and paleoclimate as an important factor to influence oil-gas generation and distribution in terrestrial deposits, emphasizing the significance of depression and humid or semihumid climates in oil and gas formation. Prof. Hou Defeng pointed out explicitly that oil in nonmarine strata was generated in inland humid geotectogenes and both oil and coal in continental basins were formed under humid climates conditions.40 years ago, the point of view on “oil-poor in China” gave the oil industry of China grey prospects. At that time, it was commonly accepted that oil was unable to be generated from terrestrial sedimentary strata. Moreover, vast areas in China were covered by continental formations and frequent crust movements in China were unfavourable to oil generation and accumulation. However, the theory on terrestrial petroleum generation summrized on the basis of the oil exploration in Northwest China smashed the trammels of this conventional viewpoint and guided the petroleum geological survey in East China. The discovery of the Daqing oilfield further demonstrated that the continental sedimentary formation could not only generate oil but also form giant oilfields.The success of the 40-years oil and gas exploration in continental basins of China has repeatedly proved that oil and gas fields are unexceptionally distributed within the centers of oil-generating depressions or adjacent areas. Owing to the quick transformation of factes in continental deposits, oil and gas usually accumulate in traps within or near oil-generating depressions when they, without long-distance migration, entered reservoirs. Therefore, the oil-generating depression is a main factor controlling oil and gas formation as well as oil and gas field distribution. One oilgenerating depression is also an oil-gas accumulating district. This theory has played a very important role in the oil and gas exploration in Mesozoic and Cenozoic nonmarine basins of China.When Prof. Hou Defeng systematically studied macrogeological phenomena and geological processes and at the same time paid great attentions to the important action of natural nuclear processes in the earth evolution. In the late 1950s, he putforward a concept of Nuclear Geology. He clearly and definitely stated that some ore-forming elements assemblages in many metallic ore deposits (such as REE, W,Nb, Ta and Zr) were related to the fission of heavy radioactive elements (such as U, Th, Pu). He systematically calculated the contribution of the radioactive nuclear energy to geothermal energy in various evolution stages of the Earth, and found that the radioactive nuclear energy dramatically affected and controlled the earth's evolution history. Meanwhile, he discussed the geological and geochemical significance of the natural nuclear process and its products. He also noticed the natural heavy radioactive isotopes, such as 239Pu and 244Pu, which were not found from natural substance of the Earth at that time but were confirmed later. In 1972, the di