Thesis: Paleoecology and evolution of Late Paleozoic microbial-algal platform carbonates, Pha Nok Khao Platform, northeastern Thailand
Carboniferous and Permian carbonate deposits below the Khorat Plateau in northeastern Thailand host major gas deposits. To the west of this region, near the city of Loei, carbonate rocks of the same age as the subsurface petroleum reservoirs are exposed at surface. These carbonates grew during the Late Carboniferous- Middle Permian within, and along the rim of, a shelf margin known as the Pha Nok Khao Platform. Previous work in this region has focused on broad-scale facies mapping, biostratigraphic dating, or tectonic reconstructions. However, there has been little detailed description of the reefal build-ups and their surrounding environments. Newly described microbial-algal reef mounds have lead to questions regarding the position of the platform margin and the distribution and composition of the platform margins build-ups through time.
This project aims to further understanding of the distribution of reef mounds on the Pha Nok Khao Platform. Detailed field mapping of several small key localities will be undertaken and samples will be analyzed petrographically and geochemically in order to describe and interpret reefal fabrics. This study will also focus on characterizing the important biological factors that promoted mound growth and how they changed during ~60 million years of platform history in the region. It is expected that in addition to providing new information that will enhance understanding of the distribution and correlation of Late Paleozoic carbonate rocks in Thailand, new descriptions of microbial-algal reef mounds can be compared with important mound-related reservoirs elsewhere around the world.
Why my research is important
Gas-prone Late Paleozoic to Mesozoic deposits of the Khorat Basin have proven to be major petroleum reservoirs. Abundant vegetation, high weathering rates and complex tectonic history complicates regional mapping and outcrop descriptions of their surface equivalents. Mapping and description of reefal build-ups is critical for understanding platform margin history and the paleogeography of the Indochina Block during the Late Carboniferous to Mid Permian. Additionally, paleoenvironmental distribution needs to be understood in order to predict the occurrence of facies with reservoir potential and to help identify regions with exploration potential in the subsurface.