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31. Mars exploration—In situK-Ar dating of jarosite

Author

Yang, Jing, Zheng, Dewen, Wu, Ying, Chen, Hong, Yang, Li, and Zhang, Bin

Abstract

To accurately determine the chronological framework of climatic variations recorded by various Martian terrains, the absolute ages of Martian events and cratering rate need to be constrained by either in situdating or returned samples. In situK-Ar dating is currently a more plausible dating technique as compared with sample return. Jarosite (KFe3[SO4]2[OH]6) is the only confirmed K sulfate mineral that is widely present on Mars, as indicated by in situdetection, orbital remote sensing, and meteorite studies. Jarosite can be used for precise K-Ar and 40Ar/39Ar dating. The preservation of jarosite on Mars provides information about the nature and duration of aqueous processes on the Martian surface. Different ages of Martian jarosite represent the key to constraining the transition from Martian surface water activity to arid climatic conditions. This paper summarizes recent advances in our knowledge of the spatial distribution of Martian jarosite, its mineralogical properties and stability on Mars, the Ar diffusion kinetics of jarosite, and the current status of in situK-Ar dating. Moreover, we examine the key scientific issues to be addressed for in situK-Ar dating of jarosite and Martian sample return missions, and discuss future research directions.

Published
2024
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42. Initial Characterisation of SK01 Sanidine: A Candidate 40Ar/39Ar Reference Material.

Author

Li, Youjuan, Jicha, Brian R., Zhang, Wanfeng, Chen, Wen, Singer, Brad S., Zheng, Dewen, and He, Huaiyu

Subjects
URANIUM-lead dating, REFERENCE sources, DETERIORATION of materials
Abstract

The precision and accuracy of 40Ar/39Ar dates are ultimately linked to co‐irradiated reference materials of known age. Here we provide new data from the SK01 sanidine, which was analysed in three different laboratories to evaluate it as a 40Ar/39Ar reference material. Aliquots of 5 mg, incrementally heated in two laboratories, yielded indistinguishable results with a weighted mean age of 27.58 ± 0.06 Ma (95% confidence level). Single‐crystal step heating and single‐crystal total fusion analyses of SK01 sanidine were undertaken in the third laboratory to further test the intracrystalline homogeneity. For the seven step‐heating analyses, six crystals yielded nearly concordant age spectra with 40Ar/39Ar ages ranging from 26.853 ± 0.094 Ma to 26.963 ± 0.067 Ma, whereas one crystal gave an older age of 27.774 ± 0.071 Ma with a slightly discordant age spectrum. Twenty‐three single‐crystal total fusion analyses yielded 40Ar/39Ar ages ranging from 27.070 ± 0.108 Ma to 27.736 ± 0.062 Ma with a dispersion of ~ 3.8%. The older ages from single‐crystal total fusion dates are interpreted to reflect an inherited or excess argon component in some crystals. This is an initial characterisation of the SK01 sanidine, and additional work needs to be conducted to further evaluate the age dispersion so that it can be utilised as a 40Ar/39Ar reference material. [ABSTRACT FROM AUTHOR]

Published
2023
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50. Quantitative Evaluation Method for Gas Loss in Underground Natural Gas Storage Reconstructed from Abandoned Gas Reservoirs

Author

Pei Gen, Liao Wei, Zheng Dewen, Zhao kai, Song Lina, Wanyan Qiqi, Wang Jieming, Xu Hongcheng, and Wang Jinkai

Subjects
Underground gas storage, Natural gas storage, Multidisciplinary, Mathematical model, Petroleum engineering, Natural gas, business.industry, Evaluation methods, Environmental science, Diffusion (business), business, Leakage (electronics), Inventory analysis
Abstract

Natural gas loss inevitably occurs during gas injection and production operation in underground gas storage. At present, the study of gas loss is only in the qualitative description stage and cannot meet the quantitative evaluation requirements for economical gas storage. Combining the theory of inventory analysis and the experimental study of the injection-production mechanism and aimed at the phenomena of microseepage, dissolution diffusion, abnormal gas leakage and macroscale gas leakage in the process of injection and production of underground natural gas storage, gas loss evaluation mathematical models are established to quantitatively evaluate the gas loss of underground natural gas storage. The results show that the gas loss in the macrodisplacement process is the main component of geological gas loss in gas storage, which decreases with increasing injection-production cycles. On this basis, a quantitative evaluation method for the natural gas loss of gas reservoir-type gas storage is established, and the accuracy and reliability of the method are verified by the gas loss calculation results of the Banzhongnanbei (BZNB) underground natural gas storage. The validation results show that the calculation error is very small, meeting the requirements of gas storage operation accuracy and providing high application value. This calculation method can effectively reduce the loss of natural gas in gas storage, provide an early warning of leakage risk, and improve the economic benefits and injection-production safety of gas storage.

Published
2021

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