DOI: 10.1306/04151513001
Scopus记录号: 2-s2.0-84947429261
论文题名: Evidence for stratigraphically controlled paleogeotherms in the Illinois Basin based on vitrinite-reflectance analysis: Implications for interpreting coal-rank anomalies
作者: Mariño J. ; Marshak S. ; Mastalerz M.
刊名: AAPG Bulletin
ISSN: 0149-1455
EISSN: 1558-9185
出版年: 2015
发表日期: 2015
卷: 99, 期: 10 起始页码: 1803
结束页码: 1825
语种: 英语
Scopus关键词: Geochronology
; Groundwater
; Mineralogy
; Reflection
; Stratigraphy
; Computer modeling
; Fluid inclusion
; Geothermal gradients
; High permeability zone
; Rate of increase
; Sedimentary basin
; Stable isotopes
; Vitrinite reflectance
; Coal
; advection
; basin analysis
; coal rank
; computer simulation
; fluid inclusion
; geothermal gradient
; heat flow
; hydrothermal circulation
; paleogeography
; Paleozoic
; stable isotope
; unconformity
; vitrinite reflectance
; Absaroka Mountains
; Illinois Basin
; Pennsylvania
; Rocky Mountains
; United States
Scopus学科分类: Energy
; Earth and Planetary Sciences
英文摘要: Coal rank reflects the temperature of coalification, with higher rank coal forming at higher temperatures. If the temperature of coalification depended only on the Earth's geothermal gradient, then the maximum rank of coal in a sedimentary basin should be directly proportional to the thickness of strata above the coal. This association does not occur in the Illinois Basin, a continental-interior basin in the midwestern United States, where the overall coal rank observed is higher than can be explained by past burial depth alone. Recognition of this anomaly has led many authors to suggest that hot groundwater flowing from south to north, during a Paleozoic basin-scale groundwater-migration event, increased coal rank. We analyzed vitrinite reflectance (Ro), a measure of rank, as a function of depth in wells across the basin to determine how paleogeotherms, representing variation in temperature with depth, change with location. Our results show that the basin can be divided into three zones: (1) in the southern zone, the paleogeo-therm varies irregularly with depth in strata above the sub-Absaroka unconformity (the contact separating Pennsylvanian and Mississippian strata); (2) in the central zone, the paleogeo-therm displays a distinct inflection at the unconformity, for the rate of increase in Ro with depth is greater above the unconformity than below the unconformity; and (3) the observed inflection in the paleogeotherm dies out northward, until, in the northern zone, the paleogeotherm has the same slope both above and below the unconformity. We propose that the inflection in the paleogeotherm of the central zone indicates that the hot groundwater responsible for causing an increase in coal rank flowed through a high-permeability zone just below the sub-Absaroka unconformity. This flow, which advected heat into Pennsylvanian strata above, cooled as it moved northward, so it did not influence the paleogeotherm in the northern zone. Preliminary studies of vein paragenesis, stable-isotope composition, and fluid-inclusions, as well as computer modeling of flow-related heat advection, support this proposal. © 2015. The American Association of Petroleum Geologists. All rights reserved.
URL: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84947429261&doi=10.1306%2f04151513001&partnerID=40&md5=058e8970b42606f74d75a8d2b9f8e950
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/13026
Appears in Collections: 过去全球变化的重建 影响、适应和脆弱性 科学计划与规划 气候变化与战略 全球变化的国际研究计划 气候减缓与适应 气候变化事实与影响
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Recommended Citation:
Mariño J.,Marshak S.,Mastalerz M.. Evidence for stratigraphically controlled paleogeotherms in the Illinois Basin based on vitrinite-reflectance analysis: Implications for interpreting coal-rank anomalies[J]. AAPG Bulletin,2015-01-01,99(10)