Comparative analysis of land and oceanic characteristics of the Yangjiang-Yitong Fault Zone and its role in basin development

The Yangjiang-Yitong Fault Zone traverses the Pearl River Mouth Basin, exerting control over the structural configuration between the eastern and western parts of the basin. Its Cenozoic reactivation and strike-slip activity significantly influenced the distribution of hydrocarbon resources across the fault zone. However, the geometric characteristics of the fault zone, including its post-activation marine and terrestrial distribution, the extent of its influence, and its segmentation, remain poorly understood. This study utilizes marine and terrestrial tectonic data, along with seismic data, to conduct a preliminary analysis of the fault zone’s geometric features and its role in basin control. Our findings indicate that the Yangjiang-Yitong Fault Zone extends from Baiyun Nanwa, across Panyu Low Uplift, through Yangjiang East Depression to Yangjiang City, Yangchun City, western Yangchun, and eastern Xinyi, spanning approximately 480 km long and 10～40 km wide. The fault zone exerts a more pronounced control over the marine domain, manifesting as a distinct NW-trending fault system and Cenozoic igneous bodies, whereas in the terrestrial domain, it is characterized by intermittent NW-trending structures and traces of deep-seated fault activity. The fault zone can be delineated into three segments: the terrestrial segment, the northern marine segment, and the southern marine segment, demarcated by the marine and terrestrial domains and the Panyu Low Uplift. In the terrestrial realm, the fault zone controls the formation of the Quaternary extensional basin known as the “Yangjiang Basin”, while in the marine realm, it governs the development of the Cenozoic rift basin, referred to as the “Yangjiang East Depression”, and the horsetail-shaped transfer faults. The evolutionary history of the fault zone is divided into three phases of formation, transformation, and reactivation. During the Himalayan orogeny, the reactivation controlled the formation of strike-slip extensional basins and horsetail-shaped faults, showing an overall arrangement of “tail end - overlapping zone - main displacement zone – overlapping zone.”