Integrated loessite-paleokarst depositional system, early Pennsylvanian Molas Formation, Paradox Basin, southwestern Colorado, U.S.A.

Evans, James E.; Reed, Jason M.

doi:10.1016/j.sedgeo.2006.07.010

Cited by 28 publications

(21 citation statements)

References 37 publications

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“…In many settings, loess accumulates very quickly, producing high temporal resolution (e.g., 1 m/ky in Rhine Valley) (Hatte et al 2001;Lang et al 2003) that rivals or exceeds any other continental depositional system, and responds directly to atmospheric conditions. Study of loess as a high-resolution paleoclimate archive has long been conducted for the Quaternary record, but loess remains an under-utilized archive for Earth's deeptime record, despite increasing recognition of deep-time loess deposits (e.g., Johnson 1989a, b;Soreghan 1992;Evans and Reed 2007;Soreghan et al 2008). The Late Carboniferous-Permian record appears to be particularly rich in occurrence and preservation of thick and widespread loess deposits (Soreghan et al 2008), and many of the finegrained red beds of this age in the North America midcontinent and elsewhere have been recently reinterpreted as paleo-loess deposits (e.g., Sweet et al 2013; Dubois et al Giles et al 2013), including units of the RKB core Foster et al 2014).…”

Section: Discussion: Why Core Continental Red Beds and Evaporites?mentioning

confidence: 99%

The paleoclimatic and geochronologic utility of coring red beds and evaporites: a case study from the RKB core (Permian, Kansas, USA)

Soreghan

Benison

Foster

et al. 2014

Int J Earth Sci (Geol Rundsch)

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Drill core is critical for robust and high-resolution reconstructions of Earth’s climate record, as well demonstrated from both marine successions and modern long-lived lake systems. Deep-time climate reconstructions increasingly require core-based data, but some facies, notably red beds and evaporites, have garnered less attention for both paleoclimatic and geochronologic analyses. Here, we highlight studies from the Rebecca K. Bounds (RKB) core, a nearly continuous, >1.6 km drill core extending from the Cretaceous to the Mississippian, recovered from the US Midcontinent by Amoco Production Company in 1988, and serendipitously made available for academic research. Recent research conducted on this core illustrates the potential to recover high-resolution data for geochronologic and climatic reconstructions from both the fine-grained red bed strata, which largely represent paleo-loess deposits, and associated evaporite strata. In this case, availability of core was instrumental for (1) accessing a continuous vertical section that establishes unambiguous superposition key to both magnetostratigraphic and paleoclimatic analyses, and (2) providing pristine sample material from friable, soluble, and/or lithofacies and mineralogical species otherwise poorly preserved in surface exposures. The potential for high-resolution paleoclimatic reconstruction from coring of deep-time loess strata in particular remains severely underutilized.

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Section: Discussion: Why Core Continental Red Beds and Evaporites?mentioning

confidence: 99%

The paleoclimatic and geochronologic utility of coring red beds and evaporites: a case study from the RKB core (Permian, Kansas, USA)

Soreghan

Benison

Foster

et al. 2014

Int J Earth Sci (Geol Rundsch)

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“…In addition, the modern speleothems and ancient analogues are commonly interpreted to reflect precipitation in meteoric environments (Mutti, ; Frisia et al ., ; Fairchild et al ., ; Evans & Reed, ; Brasier, ; Duan et al ., ; Wassenburg et al ., ). This study presents the example of dolomite speleothems that are followed by submarine isopachous dolomite cement in palaeokarst cavities of the upper Ediacaran Dengying Formation from South China.…”

Section: Introductionmentioning

confidence: 98%

Cavity‐filling dolomite speleothems and submarine cements in the Ediacaran Dengying microbialites, South China: Responses to high‐frequency sea‐level fluctuations in an ‘aragonite–dolomite sea’

et al. 2019

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Speleothems, mostly composed of calcium carbonate, are widely present in modern karst‐originated caves, but have rarely been reported in palaeokarst systems. This study presents a novel type of dolomite speleothem and subsequent submarine dolomite cement, which are widely present in the upper Ediacaran Dengying Formation in the upper Yangtze area. These precipitated materials occur in the cavity system that cuts across several peritidal cycles. The interconnected cavity networks with irregular shapes, embayed walls, internal breccias on cavity floor and their preferential development in the shallower cycle tops (for example, tepee‐deformed beds) suggest that they were initially generated by subaerial dissolution. As the earliest infills, the hemispherical protrusions, icicle‐like pendants and ground‐up columns show similar morphological features and occurrence patterns to the cave popcorn, stalactites and stalagmites, respectively. Thus, these earliest infills are speleothems resulting from associated meteoric precipitation during subaerial exposure. The isopachous growth pattern of subsequent more extensive fibrous dolomite cements points to a submarine diagenetic environment in which they were precipitated. Microscopically, the micritic to micro‐crystalline dolomite, acicular dolomite in speleothems and the subsequent fibrous dolomite share similar crystal fabrics to metastable precursors (for example, Mg‐calcite). Meanwhile, the carbon‐oxygen isotope compositions of the speleothem and fibrous dolomite, although partly altered by burial diagenesis, share a large overlap with host rock and coeval marine carbonates all over the Yangtze Platform. For these reasons, these speleothems and fibrous cements are considered to have been initially precipitated as metastable carbonate precursors in meteoric and submarine environments, respectively, and stabilized during submarine mimetic dolomitization. The cyclic occurrence of cavity systems filled with speleothems and submarine cements reflects periodic subaerial exposure and marine flooding of broad tidal flat in the upper Yangtze area, driven by high‐frequency sea‐level fluctuations. Furthermore, the Neoproterozoic seawater chemistry that favoured early dolomitization of carbonate precursor mineralogies was an advantage for the preservation of fabrics from metastable precursor minerals.

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“…; Henbest, 1958;Evans and Reed, 2007) accumulated from the early to middle Bashkirian. The presence of pisolitic ironstone suggests relatively humid conditions, with a potentially marked seasonality.…”

Section: Early To Middle Bashkirianmentioning

confidence: 99%

Impact of continental motion and dynamic glaciations on low-latitude climate during the Carboniferous: The record of the Wyoming Shelf (Western United States)

Blanchard

Fielding

Frank

2015

Palaeogeography, Palaeoclimatology, Palaeoecology

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The dynamic character of the Late Paleozoic Ice Age is evident from glacial deposits, but its impact on tropical climate is not well constrained. Global changes in climate are overprinted on longer-term paleogeographic variations, resulting in a complex time-space distribution of climate-sensitive lithologies. The significance of such lithologies in Carboniferous successions of the western United States has not been fully explored. In this study, we provide new interpretations for the paleoclimatic context of the Amsden and Tensleep Formations (Pennsylvanian, Northern Wyoming, USA). The Amsden Formation consists of a basal sandstone member overlain by red siltstones containing pisolites. Very large-scale (~10 m) cross-bedding within the basal sandstone indicates deposition in an erg environment. Iron pisoid-rich layers in the overlying member suggest an evolution toward more humid conditions. Persistent arid conditions during the middle Pennsylvanian are suggested by eolian sandstones and calcretes in the overlying Tensleep Formation. These formations were deposited on the karst topography that developed on top of the lower to middle Mississippian Madison Group. Although the development of karstic features implies that humid conditions prevailed during the late Mississippian, evaporites and evidence for early dolomitization within the formation suggest that it was deposited under arid conditions. These relationships argue for a long-term climate evolution from arid to humid during the Mississippian, and a return to arid conditions during the Pennsylvanian. This trend can be explained by the northward drift from 15°S to~12°N. A comparison with contemporaneous records reveals a diachronous evolution across western Pangaea, with the climatic conditions documented on the Wyoming Shelf being reached later in eastern North America. These relationships indicate that plate motion considerably overprints long-term climatic records. Departures from this trend, suggested by the presence of erg deposits in the basal Amsden Formation, record the overprinting of shorter periods of climate change.

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Integrated loessite-paleokarst depositional system, early Pennsylvanian Molas Formation, Paradox Basin, southwestern Colorado, U.S.A.

Cited by 28 publications

References 37 publications

The paleoclimatic and geochronologic utility of coring red beds and evaporites: a case study from the RKB core (Permian, Kansas, USA)

The paleoclimatic and geochronologic utility of coring red beds and evaporites: a case study from the RKB core (Permian, Kansas, USA)

Cavity‐filling dolomite speleothems and submarine cements in the Ediacaran Dengying microbialites, South China: Responses to high‐frequency sea‐level fluctuations in an ‘aragonite–dolomite sea’

Impact of continental motion and dynamic glaciations on low-latitude climate during the Carboniferous: The record of the Wyoming Shelf (Western United States)

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