Understanding the distribution of heat flow across Southeast Asia is important for interpreting the tectonic evolution, lithospheric structure, and thermal history of the region. Heat flow influences a wide range of geological processes, including basin subsidence, hydrocarbon maturation, magmatism, crustal deformation, and geothermal systems.
Existing compilations of heat flow measurements suggest that much of the Sundaland region exhibits relatively high heat flow compared with typical continental regions. However, despite the large number of measurements that have likely been collected during exploration and academic studies over the past several decades, relatively little of this information has entered the public domain since the major Indonesian Petroleum Association (IPA) and SEAPEX compilations produced during the late 1970s and early 1980s.
Early synthesis of available measurements indicates that elevated heat flow values are widespread across Southeast Asia. In many areas the extent of these anomalies appears greater than might be expected from simple arc or back-arc thermal processes alone, suggesting that the thermal structure of the region may be more complex than previously assumed.
Heat Flow Patterns in Sundaland
Compilation of available measurements suggests that the Sundaland region is characterised by large areas of relatively high heat flow. Maps derived from early datasets and global compilations indicate that many parts of Southeast Asia exceed average continental heat flow values.
Several factors may contribute to these elevated thermal conditions. Heat within the crust commonly originates from radiogenic decay within crustal rocks, particularly granites that contain relatively high concentrations of radioactive elements. Such granitic bodies are widespread in parts of Southeast Asia and may also occur within basement rocks beneath offshore sedimentary basins. Sediments derived from these granitic terrains may also contribute to regional heat production.
Another possible explanation relates to the tectonic history of the region, particularly the widespread development of sedimentary basins associated with extension. If these basins formed during periods of lithospheric stretching, elevated heat flow may reflect the thermal consequences of crustal thinning and mantle upwelling during basin formation.
Understanding the origin of these thermal patterns has important implications for reconstructing the tectonic development of Southeast Asia and for interpreting the thermal evolution of its sedimentary basins.
Heat Flow and Basin Evolution
Heat flow plays a central role in the evolution of sedimentary basins. Variations in heat flow affect geothermal gradients, burial temperatures, and the timing of hydrocarbon generation. In regions such as Southeast Asia, where sedimentary basins can contain very thick successions of sediments, understanding past heat flow is essential for reconstructing basin histories.
Elevated heat flow may be associated with:
- crustal extension and basin formation
- magmatic activity and volcanic arcs
- radiogenic heat production in granitic crust
- mantle processes beneath active plate boundaries
By compiling and analysing regional heat flow data it becomes possible to evaluate how these processes have influenced the thermal structure of Southeast Asia through time.
Heat Flow Compilation
To improve understanding of the thermal structure of Southeast Asia, SEARG has compiled available heat flow measurements from published datasets and global databases. These include data derived from:
- early IPA and SEAPEX publications
- global heat flow compilations such as those from the National Geophysical Data Center (NGDC)
- subsequent academic studies of heat flow across Asia
A regional compilation map summarising these measurements highlights areas where heat flow values exceed typical continental averages. In this compilation, areas shaded in green represent values close to average continental heat flow, whereas yellow, orange, and red colours indicate progressively higher values.
This compilation emphasises both the regional extent of elevated heat flow and the uneven distribution of available measurements.
Future Data Compilation
A major aim of this work is to expand the existing dataset by incorporating heat flow measurements collected since the early regional compilations of the 1970s and 1980s. Many additional measurements are likely to exist within exploration datasets or unpublished reports.
We therefore aim to compile a more comprehensive regional heat flow database that will include measurements from wells and other sources across Southeast Asia. This dataset will help improve regional coverage and allow more detailed analysis of the thermal structure of the region.
The SE Asia heat flow database will be made available on this page in due course.
Researchers and companies with relevant data are encouraged to contribute measurements so that a more complete regional dataset can be assembled.
Southeast Asia Research Group 