气候变化领域集成服务门户(CCPortal): Paleothermometry and distribution of calcite beef in the Vaca Muerta Formation; Neuquén Basin; Argentina

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DOI	10.1306/10021817384
	Paleothermometry and distribution of calcite beef in the Vaca Muerta Formation; Neuquén Basin; Argentina
	Weger R.J.; Murray S.T.; McNeill D.F.; Swart P.K.; Eberli G.P.; Rodriguez Blanco L.; Tenaglia M.; Rueda L.E.
发表日期	2019
ISSN	0149-1423
起始页码	931
结束页码	950
卷号	103 期号:4
英文摘要	The term “beef” describes bedding-parallel calcite veins found commonly in the organic-rich matrix of unconventional resource plays. Although some authors have interpreted beef to be an early diagenetic feature, these calcite veins are commonly attributed to precipitation at high temperatures and localized overpressure during hydrocarbon generation. The temperature at which the beef formed is thus crucial to ascertain the process of beef genesis. We use the novel methodology of clumped isotope analysis to constrain both the temperature at which beef forms and the isotopic composition of fluids present during formation. For this study, we use beef from basinal sections of the Vaca Muerta Formation in the Neuquén Basin, where veins are commonly up to approximately 10 cm (~4 in.) thick and are laterally continuous over 1 km (0.6 mi). The calcite veins occur in isolation or in association with concretions and ash layers. Sequence stratigraphic boundaries have little influence on distribution, and only a low correlation between beef and total organic content or beef and ash layers exists. The internal crystal structure of beef varies largely, suggesting both syntaxial and antitaxial growth forms. The d18O values of beef range from approximately -12 to -9, and the d13C values vary between approximately -1 and 1. The surrounding mudstone and concretion fracture fills (calcite) show little difference isotopically when compared to the beef itself. The d18O values of nearby concretions range from approximately -3.5 to 1, and the d13C values vary between approximately 6 and 11. Clumped isotope analysis of beef in the Vaca Muerta Formation indicates temperatures between approximately 140°C and 195°C, whereas the surrounding mudstones vary from approximately 120°C to 150°C. The corresponding formation fluid d18Ow values range from 8.5 to 14.5. These temperature data are higher than the maximum temperatures suggested by published studies modeling the basin’s thermal and burial histories. If these models are correct, the clumped isotope data indicate that the growth of beef in the Vaca Muerta Formation required the input of hydrothermal fluids from greater depths. Alternatively, the geothermal gradient or burial depth was underestimated in these models. Copyright ©2019. The American Association of Petroleum Geologists. All rights reserved.
语种	英语
scopus关键词	Calcite; Crystal structure; Isotopes; Resource valuation; Sedimentary rocks; Stratigraphy; Geothermal gradients; Hydrocarbon generation; Hydrothermal fluids; Isotopic composition; Maximum temperature; Novel methodology; Total organic contents; Unconventional resources; Beef; calcite; carbon isotope; hydrocarbon generation; hydrothermal fluid; isotopic analysis; isotopic composition; mudstone; paleotemperature; Argentina; Neuquen Basin
来源期刊	AAPG Bulletin
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/143768
作者单位	Comparative Sedimentology Laboratory (CSL), Center for Carbonate Research, Department of Marine Geosciences, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL, United States; CSL, Center for Carbonate Research, Department of Marine Geosciences, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL, United States; Macquarie University, North Ryde, NSW, Australia
推荐引用方式 GB/T 7714	Weger R.J.,Murray S.T.,McNeill D.F.,et al. Paleothermometry and distribution of calcite beef in the Vaca Muerta Formation; Neuquén Basin; Argentina[J],2019,103(4).
APA	Weger R.J..,Murray S.T..,McNeill D.F..,Swart P.K..,Eberli G.P..,...&Rueda L.E..(2019).Paleothermometry and distribution of calcite beef in the Vaca Muerta Formation; Neuquén Basin; Argentina.AAPG Bulletin,103(4).
MLA	Weger R.J.,et al."Paleothermometry and distribution of calcite beef in the Vaca Muerta Formation; Neuquén Basin; Argentina".AAPG Bulletin 103.4(2019).