Electron spin resonance (ESR) dating of pre-Quaternary faults in the Sichuan basin, SW China

Qiu, Dengfeng; Liu, Quanyou; Yun, Jinbiao; Jin, Zhijun; Zhu, Dongya; Li, Tianyi; Sun, Dongsheng

doi:10.1016/j.jseaes.2018.06.011

Cited by 2 publications

(1 citation statement)

References 35 publications

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“…This radiation produces defects in the crystal lattice that can trap electrical charges that eventually form a "paramagnetic center" that produces a detectable signal in ESR spectrometry. The height (intensity) of the spectrum obtained is proportional to the number of electrons trapped in each paramagnetic center, the radiation dose and its duration (Ikeya et al, 1982;Ikeya, 1993, Grün, 1989Lee and Schawarcz, 1994;Lee and Yang, 2007;Qju et al, 2018;Duval, 2018).…”

Section: Geochronology Of Fault Rocksmentioning

confidence: 99%

Geological-structural mapping and geocronology of shear zones: A methodological proposal

Ortega¹,

Isaza²,

Herrera³

et al. 2021

Bol.geol.

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The deformation registered in rocks in the field can be characterized based on the structures preserved in outcrops, which can related be to wide discontinuity zones named faults and shear zones. The geological-structural mapping and the geochronology of these tectonic structures are a topic of great interest not only for tectonic modeling but also for reconstruction of the geological evolution of the national territory. The methodology suggest for the analysis of faults and shear zones is based on eight steps, including: 1) definition of the geological context in which the structure was developed; 2) photointerpretation, image geoprocessing, and geological-structural mapping of the structural and lithological characteristics of the faults and shear zones; 3) petrographic analysis of field-oriented samples; 4) quantification of strain orientation and geometry through 3D finite strain analyses and quantification of non-coaxiliaty of deformation through vorticity analyses; 5) SEM-TEM-EBSD microanalysis; 6) quantification of the P-T conditions of deformation through phase-equilibria modeling or conventional geothermobarometry; 7) dating of syn-kinematic minerals phases and mylonitic rocks through Ar-Ar analyses, in order to determine the reactivation and deformation ages of the structure, respectively, as well as the implementation of the U-Pb technique in syn-kinematic calcite crystals developed in the fault planes; and 8) dating of geological elements adjacent to the structure, such as syn-kinematic intrusive bodies associated with the deformation event using zircon U-Pb dating, rocks hydrothermally altered through Ar-Ar method, and zircon and apatite fission-tracks dating of the blocks adjacent to the faults for determining exhumation ages.

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Section: Geochronology Of Fault Rocksmentioning

confidence: 99%

Geological-structural mapping and geocronology of shear zones: A methodological proposal

Ortega¹,

Isaza²,

Herrera³

et al. 2021

Bol.geol.

View full text Add to dashboard Cite

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Natural fractures in tight gas sandstones: a case study of the Upper Triassic Xujiahe Formation in Xinchang gas field, Western Sichuan Basin, China

et al. 2021

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The Upper Triassic Xujiahe Formation is a typical tight gas reservoir in which natural fractures determine the migration, accumulation and production capacity of tight gas. In this study, we focused on the influences of natural fractures on the tight gas migration and production. We clarified characteristics and attributes (i.e. dips, apertures, filling degree and cross-cutting relationships) of the fractures based on image logging interpretations and core descriptions. Previous studies of electron spin resonance, carbon and oxygen isotopes, homogenization temperature of fluid inclusions analysis and basin simulation were considered. This study also analysed the fracture sequences, source of fracture fillings, diagenetic sequences and tight gas enrichment stages. We obtained insight into the relationship between fracture evolution and hydrocarbon charging, particularly the effect of the apertures and intensity of natural fractures on tight gas production. We reveal that the bedding fractures are short horizontal migration channels of tight gas. The tectonic fractures with middle, high and nearly vertical angles are beneficial to tight gas vertical migration. The apertures of fractures are controlled by the direction of maximum principal stress and fracture angle. The initial gas production of the vertical wells presents a positive correlation with the fracture abundance, and the intensity and aperture of fractures are the fundamental factors that determine the tight gas production. With these findings, this study is expected to guide the future exploration and development of tight gas with similar geological backgrounds.

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Electron spin resonance (ESR) dating of pre-Quaternary faults in the Sichuan basin, SW China

Cited by 2 publications

References 35 publications

Geological-structural mapping and geocronology of shear zones: A methodological proposal

Geological-structural mapping and geocronology of shear zones: A methodological proposal

Natural fractures in tight gas sandstones: a case study of the Upper Triassic Xujiahe Formation in Xinchang gas field, Western Sichuan Basin, China

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