Abstract:

About 60% oil and gas of the world is produced from carbonate rocks. Where and when are carbonate rocks most developed in the world? What are the controlling factors? To figure out these questions is not only important to selection of strategic exploration areas abroad, but also important to understanding of global paleogeography. Based on various data from 179 carbonate basins in the world，global distribution of Phanerozoic carbonates and the controlling factors were studied in this paper. Carbonates occur in every geological period, but the degree of development is different. In the Devonian, Cretaceous and Paleogene, carbonates were widely spread, while in the Silurian, Permian, Triassic and Jurassic, distribution of carbonates  was limited. In different geological periods, carbonates are developed in different areas. From the Cambrian to Ordovician, carbonates mainly occurred in Russia, China, North America and Australia. After the Triassic, carbonates mainly occurred in the Middle East, South Europe, North Africa and South America. In the Cenozoic, carbonates mainly occurred in the Middle East, North Africa and South Asia. Continental drifts and sea level change controlled distribution of carbonates. In the Paleozoic, the Laurasia (current Eurasia and North America), Siberia, South China and Australia were in low latitudes, where the sea was warm and carbonates were developed. But the Gondwana continent (current Africa and South America) were in high latitudes, where the sea was cold and not favorable for carbonate deposition. In the Mesozoic, the Laurasia drifted to high latitudes and thus little carbonates were deposited, while the Gondwana broke up and drifted to low latitudes and abundant carbonates were developed in South America and North Africa. In the Cenozoic, the Middle East and South Asia were in low latitudes and carbonates were developed. Thus carbonates distribution is well correlated with continental drift. Fluctuation of sea level is another important factor controlling the distribution of carbonates. When sea level rises, continental seas are widely formed, providing favorable sites for deposition of carbonates.When sea level falls, continent marginal seas are developed, which are not favorable for deposition of carbonates.

Key words: carbonate rock, global distribution, continental drift, fluctuation of sea level, controlling factor