Time-capsule concretions: Unlocking burial diagenetic processes in the Mancos Shale using carbonate clumped isotopes

Dale, Annabel; John, Cédric M.; Mozley, Peter S.; Smalley, P. C.; Muggeridge, Ann

doi:10.1016/j.epsl.2014.03.004

Cited by 115 publications

(80 citation statements)

References 46 publications

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“…The use of clumped isotopes permitted them to calculate temperatures independent of the isotopic composition of the fluid. Dale et al (2014) observed values of d 18 O similar to those we observed in the tabular calcite crystals, and calculated temperatures of *100°C, requiring burial of the concretion at a depth of *3500 m at the time of septarian carbonate precipitation. These conditions seem unlikely for our concretion and we conclude that meteoric groundwater is a more likely source for the light d 18 O and d 13 C values of the fracture calcite.…”

Section: Post-depositional Historysupporting

confidence: 79%

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3-D orientation and distribution of ammonites in a concretion from the Upper Cretaceous Pierre Shale of Montana

Landman

Grier²,

Grier

et al. 2015

Swiss J Palaeontol

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One of the most common modes of preservation of ammonites in the Upper Cretaceous US Western Interior is in concretions. We examine an accumulation of ammonites from a single concretion in the lower Maastrichtian Pierre Shale of eastern Montana. The concretion is an oblate spheroid 50 cm in length and 26 cm in diameter, with its long axis parallel to the substrate. It contains approximately 90 ammonite specimens representing three species of Hoploscaphites including adults and juveniles. The concretion also contains other fauna, primarily bivalves and gastropods. A total of 33 ammonites, mostly adults, are concentrated in a cluster that spans 71 % of the length of the concretion (called the ''sculpture''). 3-D measurements of the ammonites in the sculpture reveal that (1) the shells dip at all angles, with a significant trend toward more horizontal from west to east; (2) the shells dip with a highly significant bias toward the east, suggesting a current from that direction; and (3) a highly significant number of the shells that are non-vertical face with their left side up. Most of the shells show lethal damage as indicated by missing pieces of body chamber. After settling to the bottom, the shells may have piled up against each other, creating a sediment trap. Other organisms such as scavenging gastropods may have been attracted to the site to feed on the stranded ammonite carcasses. The chambers of the ammonite phragmocones and even some of the body chambers are empty, suggesting relatively rapid burial. Oxygen and carbon isotopic analyses of the ammonite shells reveal that they preserve their original isotopic signature. The values of d 13 C of the carbonate cement in the concretionary matrix are much lighter than those in the ammonite shells and imply that cementation of the concretion occurred in association with the decomposition of organic matter.

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Section: Post-depositional Historysupporting

confidence: 79%

“…Dale et al (2014) used carbonate clumped isotopes to examine the temperature of formation of the carbonate in septarian fractures in concretions from the Mancos Shale. The use of clumped isotopes permitted them to calculate temperatures independent of the isotopic composition of the fluid.…”

Section: Post-depositional Historymentioning

confidence: 99%

3-D orientation and distribution of ammonites in a concretion from the Upper Cretaceous Pierre Shale of Montana

Landman

Grier²,

Grier

et al. 2015

Swiss J Palaeontol

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“…Clumped isotope-derived temperatures can be combined with ␦ 18 O carb to uniquely determine ␦ 18 O w through application of an appropriate carbonate-water oxygen isotope fractionation factor (Kim and O'Neil, 1997;Vasconcelos et al, 2005). The tool has been used for a range of applications including the study of primary and diagenetic processes in terrestrial and marine samples of a wide range of ages (Came et al, 2007;Affek et al, 2008;Dennis and Schrag, 2010;Eagle et al, 2010Eagle et al, , 2011Eagle et al, , 2013Passey et al, 2010;Tripati et al, 2010Tripati et al, , 2014Bristow et al, 2011;Ferry et al, 2011;Finnegan et al, 2011;Huntington et al, 2011;Keating-Bitonti et al, 2011;Loyd et al, 2012aLoyd et al, , 2013aLoyd et al, , 2014Passey and Henkes, 2012;Swanson et al, 2012;Dale et al, 2014).…”

Section: Figmentioning

confidence: 99%

Evolution of Neoproterozoic Wonoka–Shuram Anomaly-aged carbonates: Evidence from clumped isotope paleothermometry

Loyd

Corsetti

Eagle

et al. 2015

Precambrian Research

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a b s t r a c tThe Wonoka-Shuram Anomaly represents the largest negative carbon isotope excursion recognized in the geologic record and is associated with the emergence and diversification of metazoan life ca. 580 million years ago (Ma). The origin of the anomaly is highly debated, with interpretations ranging from primary to diagenetic, each having unique and potentially transformative implications for early life. Here, we apply carbonate clumped isotope thermometry to three sections expressing the anomaly in order to constrain mineral formation temperatures and thus directly calculate water oxygen isotope compositions (␦ 18 O w ) with which carbonate minerals equilibrated. With ␦ 18 O w known, it is possible to address previous hypotheses for the origin of the anomaly. In each section, precipitation temperatures correlate positively with reconstructed ␦ 18 O w . Previous hypotheses, based on the covariance of ␦ 18 O carb vs. ␦ 13 C carb (uncorrected for temperature effects), suggested a meteoric diagenetic origin for the anomaly. However, reconstructed ␦ 18 O w values do not covary with carbon isotope compositions (␦ 13 C carb ) within anomaly facies. Rather, the oxygen isotope and temperature data are consistent with carbonate recrystallization and equilibration under increasingly rock-buffered conditions. Based on simple modeling and comparison to modern formation fluids, recrystallization may have occurred in an environment far removed from the initial depositional or early diagenetic regime. In addition, although clumped isotope temperatures vary significantly and reach elevated values consistent with burial diagenesis, it is unclear to what degree, if at all, carbon isotope values were reset during recrystallization. Ultimately, these new data indicate that Wonoka-Shuram-aged carbonates experienced equilibration with fluids under increasingly closedsystem conditions. The clumped isotope data do not provide a means to distinguish previous hypotheses outright, but provide additional context for the evaluation of geochemical signatures within these ancient carbonate rocks.

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“…Some authors suggest that concretions commonly form during early burial at or just below the sediment-water interface, sometimes during single precipitation episodes (Hudson 1978;Carpenter et al 1988;Mozley and Burns 1993;Duck 1995;Middleton and Nelson 1996;Raiswell and Fisher 2000;Woo and Khim 2006). These shallow-burial concretions can preserve aspects of the original groundwater chemistry and depositional sedimentary fabric (Canfield and Raiswell 1991;Mozley and Burns 1993;El Albani et al 2001;Roberts and Chan 2010;Dale et al 2014), which can be useful for interpreting environments of deposition at sites where facies analysis is otherwise difficult because of limited or no exposed host rock. For example, stable-isotope analysis of concretion cement can indicate the influence of marine or meteoric water during cement precipitation (Anderson and Arthur 1983;Hays and Grossman 1991;Faure and Mensing 2005;Zhou et al 2008), but can be relied upon only if the cement formed during shallow burial, thereby truly reflecting the geochemical signature of the environment of deposition.…”

mentioning

confidence: 99%

Depositional Environment of the Lower Cretaceous (Upper Albian) Winton Formation At Isisford, Central-West Queensland, Australia, Inferred From Sandstone Concretions

Syme¹,

Welsh²,

Roberts³

et al. 2016

Journal of Sedimentary Research

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Numerous vertebrate and plant fossils have been found in ex-situ sandstone concretions near Isisford in central-west Queensland since the mid-1990s. These concretions are found in the Lower Cretaceous portion (upper Albian, 100.5-102.2 Ma) of the Winton Formation. The lower most Winton Formation is thought to have formed in a fluvial channel or flood-basin setting proximal to the Eromanga Sea, but due to the scarcity of good exposures, the local depositional environment at Isisford has not been ascertained. Minimal compression of vertebrate and plant fossils, a lack of grain suturing, predominantly cement-supported fabric, and fractures running through calcite cement, as well as fossil bone and framework grains, indicates that concretions formed during early diagenesis (pre-compactional or syndepositional). Calcite stable-isotope δ 18 O VPDB values range from -12.25 to -4‰, indicating mixed marine and meteoric pore waters, and δ 13 C VPDB values range from -5.3 to 4.1‰, indicative of both sulfate reduction and methanogenesis of organic material (including decaying vertebrate soft tissues) in the burial environment. The mixed marine and freshwater signature suggests a marginal marine setting, possibly deltaic or estuarine, connected to the regressive epicontinental Eromanga Seaway at around 102-100 Ma. This is not inconsistent with the lithology from nearby cores, coupled with Isisford fossil-vertebrate ecology (personal observation). Our research demonstrates the utility of investigating ex-situ concretions to refine paleoenvironments at localities where little or no outcrop is available and traditional facies analysis is impractical. INTRODUCTIONSandstone concretions cemented with calcium carbonate have been reported worldwide, ranging from the centimeter scale (Dix and Mullins 1987;Allison and Pye 1994;Mozley and Davis 2005; Tabor et al. 2007), the decimeter to meter scale (Dix and

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Time-capsule concretions: Unlocking burial diagenetic processes in the Mancos Shale using carbonate clumped isotopes

Cited by 115 publications

References 46 publications

3-D orientation and distribution of ammonites in a concretion from the Upper Cretaceous Pierre Shale of Montana

3-D orientation and distribution of ammonites in a concretion from the Upper Cretaceous Pierre Shale of Montana

Evolution of Neoproterozoic Wonoka–Shuram Anomaly-aged carbonates: Evidence from clumped isotope paleothermometry

Depositional Environment of the Lower Cretaceous (Upper Albian) Winton Formation At Isisford, Central-West Queensland, Australia, Inferred From Sandstone Concretions

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