YBCs sanidine: A new standard for 40Ar/39Ar dating

Wang, Fei; Jourdan, Fred; Lo, Ching‐Hua; Nomade, Sébastien; Guillou, Hervé; Zhu, Rixiang; Yang, Liekun; Shi, Wenbei; Feng, Huile; Wu, Lin; Haiqing, Sang

doi:10.1016/j.chemgeo.2014.09.003

Cited by 27 publications

(9 citation statements)

References 24 publications

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“…. Ages were calculated against the international standard YBCs sanidine (29.286 ± 0.045 Ma49). The experiments were conducted on an MM5400 mass spectrometer; plateau ages were calculated using adjacent ages of step-heating that agreed within a range of 2σ.…”

Section: Methodsmentioning

confidence: 99%

Differential growth of the northern Tibetan margin: evidence for oblique stepwise rise of the Tibetan Plateau

Wang

Shi

Zhang

et al. 2017

Sci Rep

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Models of how high elevations formed across Tibet predict: (a) the continuous thickening of a “viscous sheet”; (b) time-dependent, oblique stepwise growth; and (c) synchronous deformation across Tibet that accompanied collision. Our new observations may shed light on this issue. Here, we use 40Ar/39Ar and (U-Th)/He thermochronology from massifs in the hanging walls of thrust structures along the Kunlun Belt, the first-order orogenic range at the northern Tibetan margin, to elucidate the exhumation history. The results show that these massifs, and hence the plateau margin, were subject to slow, steady exhumation during the Early Cenozoic, followed by a pulse of accelerated exhumation during 40–35 Ma. The exhumation rate increases westward (from ~0.22 to 0.34 and 0.5 mm/yr). The two-fold increase in exhumation in the western part (0.5 mm/yr) compared to the eastern part suggests westward increases in exhumation and compressional stress along the Kunlun Belt. We relate these observations to the mechanisms responsible for the oblique stepwise rise of Tibet. After collision, oblique subduction beneath Kunlun caused stronger compressional deformation in the western part than in the eastern part, resulting in differential growth and lateral extrusion.

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Section: Methodsmentioning

confidence: 99%

Differential growth of the northern Tibetan margin: evidence for oblique stepwise rise of the Tibetan Plateau

Wang

Shi

Zhang

et al. 2017

Sci Rep

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“…Aliquots from both the samples, each containing 10 grains, were wrapped in aluminum foil to form wafers and stacked in quartz vials with the international standard YBCs (29.286 ± 0.045 Ma; Wang et al, 2014). Neutron irradiation was carried out in position H8 of the 49-2 Nuclear Reactor (49-2 NR), Beijing (China), with a flux of ~6.5 × 10 12 n (cm 2 s) -1 for 24 h. The CO 2 laser fusion step-heating technique was used for 40 Ar/ 39 Ar analyses.…”

Section: Ar/ 39 Ar Datingmentioning

confidence: 99%

Nature of Cretaceous dolerite dikes with two distinct trends in the Damodar Valley, eastern India: Constraints on their linkage to mantle plumes and large igneous provinces from 40Ar/39Ar geochronology and geochemistry

et al. 2019

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Two distinct sets of Cretaceous dolerite dikes intrude the Chhotanagpur gneissic complex of eastern India, mostly within the Damodar Valley Gondwanan sedimentary basins. One dike set trends NNE to ENE, whereas the other set, which includes the prominent Salma dike, trends NW to NNW. One dike from each set in the Raniganj Basin was dated using the 40Ar/39Ar method in order to resolve a controversy concerning the emplacement age of the Salma dike. The NE-trending dike yielded a plateau age of 70.5 ± 0.9 Ma, whereas the NNW-trending Salma dike is much older, with a plateau age of 116.0 ± 1.4 Ma. These results demonstrate that the Salma dike was emplaced at ca. 116 Ma and not at ca. 65 Ma, as suggested in an earlier study. Geochemical characteristics of the two dikes are also distinct and indicate that they belong to previously identified high-Ti and low-Ti dolerite groups, respectively. The observed geochemical characteristics of both dike sets are comparable with the geochemistry of basalts of the Kerguelen Plateau, Bunbury Island, and Rajmahal Group I and suggest a connection to mantle plumes. The new age data presented herein indicate that these two magmatic episodes in the eastern Indian Shield were related to the ca. 120–100 Ma Kerguelen mantle plume and its associated Greater Kerguelen large igneous province and the ca. 70–65 Ma Réunion plume and its associated Deccan large igneous province, respectively.

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“…The diameter of aluminum wafers was 4.0 mm, and the thickness was 0.5-0.75 mm. The samples were packed into a silica tube with standard YBCs sanidine (Yabachi sanidine) flux monitors and sealed under vacuum [27]. The samples were irradiated on the B4 channel of the 49-2 nuclear reactor at the China Institute of Atomic Energy, China.…”

Section: Ar/ 39 Ar Datingmentioning

confidence: 99%

Geologically Meaningful 40Ar/39Ar Ages of Altered Biotite from a Polyphase Deformed Shear Zone Obtained by in Vacuo Step-Heating Method: A Case Study of the Waziyü Detachment Fault, Northeast China

Shi

Wang

et al. 2020

Minerals

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Discordant biotite 40Ar/39Ar age spectra are commonly reported in the literature. These can be caused by a number of processes related to in vacuo heating, homogenization of the argon distribution, and production of misleadingly flat age spectra. Problematic samples are typically derived from metamorphic belts; thermal overprinting and chloritization are two of the main known causes of disturbed age spectra. Biotite and muscovite of the Waziyü detachment fault, Yiwulüshan metamorphic core complex, Jinzhou, China, yield highly variable 40Ar/39Ar data that hinder reconstruction of their deformation history. We combined mineralogical studies with detailed 40Ar/39Ar dating of biotite, phengitic white mica, and K-feldspar augen from this fault. We infer that argon within the biotite was modified by hydrothermal fluids during fault activity and associated epidotization, chloritization, and muscovitization such that bulk sample step-heating, single grain total fusion, and in situ laser ablation of biotite produced mixed 40Ar/39Ar ages. However, detailed step-heating of biotite shows that this mineral records the ages of cooling and later alteration based on data from a coexisting rigid feldspar porphyroblast and neo-crystallized phengite that record two periods of fault activity at ~120–113 and 18–12 Ma. Our data reveal that the discordant biotite 40Ar/39Ar age spectra might represent a mixed age and that only detailed step-heating methods can extract meaningful geological details of the deformation history of a fault. Therefore, the mineral and the method must be carefully considered if metamorphic or deformed samples are dated.

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YBCs sanidine: A new standard for 40Ar/39Ar dating

Cited by 27 publications

References 24 publications

Differential growth of the northern Tibetan margin: evidence for oblique stepwise rise of the Tibetan Plateau

Differential growth of the northern Tibetan margin: evidence for oblique stepwise rise of the Tibetan Plateau

Nature of Cretaceous dolerite dikes with two distinct trends in the Damodar Valley, eastern India: Constraints on their linkage to mantle plumes and large igneous provinces from 40Ar/39Ar geochronology and geochemistry

Geologically Meaningful 40Ar/39Ar Ages of Altered Biotite from a Polyphase Deformed Shear Zone Obtained by in Vacuo Step-Heating Method: A Case Study of the Waziyü Detachment Fault, Northeast China

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