Formation process and controlling factors of tight buried-basement hill reservoirs:a case study of Weixinan Depression, Northern Beibu Gulf Basin, South China

Frontiers in Earth Science, Journal Year: 2025, Volume and Issue: 13

Published: April 11, 2025

In relatively stable sedimentary basins, the formation of buried-basement hill reservoirs mainly occurs after basin basement forms and before overlying cover layer is filled. Represented by Beibu Gulf Basin in South China Sea, are key targets for hydrocarbon exploration deep basins. Limited research hills hinder understanding accumulation conditions, thereby restricting large-scale exploration. Geophysical methods, including balanced section method stress field analysis, were used to restore burial processes buried-hills Weixinan Depression Basin. The process these consists five stages diapiric uplift (Caledonian period), thrust (Indosinian-Yanshanian multiple exposure (Late Caledonian, Indosinian-Yanshanian burials (Hercynian period Early Himalayan Period), finalization Period). Three controlling factors determined: ①differences degree granite intrusion lead differences karst paleogeomorphology; ②thrust movement NE-SW direction during Hercynian period; ③ NW-SE Indosinian-Yanshanian. main development buried-carbonate multi-stage tectonic stress, karstification, lithology. tight reservoir composed dissolved pore fracture concentrated horizontal underflow zone. buried-granite (or metamorphic rock) karstification. leaching zone located at top each rocks hill.

Language: Английский

Repeated Structural Reworking in the Basement of the Central Colombian Andes Unraveled by a Multi‐Chronometric Approach

Tectonics, Journal Year: 2024, Volume and Issue: 43(10)

Published: Oct. 1, 2024

Abstract Long‐lived orogens are often characterized by basement blocks affected polyphase thick‐skinned deformation. Deciphering these events is challenging due to the heterogeneous and complex structural histories resulting from superposition of multiple deformation phases. For instance, Central Cordillera Colombia was shaped tectonic phases during Mesozoic Cenozoic, which have been poorly constrained in both space time. To unravel history this mountain belt, we conducted field mapping applied a multi‐chronometric approach that included zircon apatite U‐Pb dating igneous basement, epidote titanite structurally controlled mineralization events, K‐Ar fault rock illite, fission track (U‐Th‐Sm)/He bedrock thermochronology zircon. The results reveal six along two systems past 184 Myr. This started Jurassic with magmatism ductile deformation; followed brittle‐ductile fluid‐assisted basin subsidence inversion Cretaceous. Finally, Cenozoic brittle strike‐slip compressional Our findings show response reworking, highlighting prominent role ancient upper‐plate discontinuities, magmatism, fluids.

Language: Английский

Mineral fabrics unravel syn-magmatic deformation and constrain Permian and Jurassic tectonic regimes in arc plutons from the southern Colombian Andes

International Geology Review, Journal Year: 2024, Volume and Issue: unknown, P. 1 - 22

Published: Oct. 15, 2024

Mineral fabric analyses of Permian La Plata and Jurassic Paez arc plutons provide information about the interplay tectonic deformation magma emplacement in southern Colombian Andes. We combined field mapping, microstructural data, AMS fabrics, rock magnetic properties, vorticity analysis, thermobarometry to study internal fabrics plutons. Our results indicate that studied have well-developed NE magmatic mylonitic foliations, with latter being distinctive for pluton. These foliations are consistent N65°E/63°W N43°E/82°W fabrics. Magnetic lineations record subhorizontal (Permian) vertical (Jurassic) magmas upwards NE–SW trajectories. The orientations all plutonic structurally controlled compressional tectonics bulk NW–SE crustal shortening. Microstructural features recorded reveal sub-magmatic solid-state developed at high- low-temperatures during their syn-tectonic history. Thermobarometric calculations similar shallow conditions (~10 km depth) application analysis shows syn-emplacement pluton by simple-shear dominated dextral transpression, whereas intrusion may been associated pure-shear contractional deformation.

Language: Английский