Insights on the structural framework of the Ailaoshan Orogenic Belt from gravity data

Abstract

One of the important tasks in mapping geological structures is determining the horizontal boundaries of density structures. These boundaries can be estimated by using the edge detection techniques for gravity data. In this study, we apply several traditional edge enhancement filters along with recently developed techniques to the Bouguer gravity data to analyze structural trends and fault zones in the Ailaoshan Orogenic Belt, which is known as a significant suture zone between the South China Block and the Indochina Block. The edge recognition capabilities of these filters are examined using both noise-free and noisy synthetic gravity data before applying them to real gravity anomaly data of the Ailaoshan Orogenic Belt area. The structural features from the edge detection techniques are also confirmed by the Euler deconvolution method, where the result shows that the depth estimates in the Ailaoshan Orogenic Belt change from 0.9 to 4.7 km. The findings show that edge detection techniques produce anomaly maps that are well-correlated with the main tectonic framework of the study area, which trends NW-SE. These techniques are also helpful in identifying some structural features that are not visible at the surface, thus contributing to a more complete crustal framework of the Ailaoshan Orogenic Belt.