Abstract:

Igneous rock intrusions are extensively distributed in the western Shunbei area， Tarim Basin， playing a significant role in transforming stratigraphic architecture and petroliferous systems. However， there is a lack of clear understanding of their characteristics and coupling relationships with deep strike-slip fault zones. Using the latest 2D and 3D seismic data of the area， we present a fine-scale characterization of their morphological features， categorizing their types and combinations. Furthermore， we identify their developmental stages and define their coupling relationships with deep strike-slip faults. The results show that the igneous rock intrusions in the western Shunbei area exhibit multiple morphotypes， including stratum-concordant， tongue-， saucer-， and half-saucer-shaped intrusions. Individual intrusive sheets can combine to form sill complexes through processes of conjunction， connection， and fault-induced dislocation. The igneous intrusions in the Shunbei area predominantly occur between the tops of the Middle-Lower Ordovician and the Middle-Lower Devonian， with the activity types of intrusive sheets being categorized into single-stage and single-layer， single-stage and multi-layer， and multi-stage and multiple-layer types. Unconformities and faults， acting as magma conduits， dictate the quantity and scale of the igneous rock intrusions， leading to notable disparities in igneous rock intrusions between the southern and northern parts of the study area. Specifically， the northern part of the study area featuring the deep strike-slip faults serving as primary magma conduits， exhibits intense vertical magma intrusion. In contrast， the southern part featuring unconformities acting as magma conduits， shows stronger horizontal magma intrusion.

Key words: fault, unconformity, coupling with faults, igneous rock intrusion, strike-slip fault zone, western Shunbei area, Tarim Basin