An astronomically calibrated stratigraphy of the Cenomanian, Turonian and earliest Coniacian from the Cretaceous Western Interior Seaway, USA: Implications for global chronostratigraphy

Eldrett, James S; Ma, Changqian; Bergman, Steven C.; Lutz, Brendan P.; Gregory, F. John; Dodsworth, Paul; Phipps, Mark; Hardas, Petros; Minisini, Daniel; Ozkan, Aysen; Ramezani, J.; Bowring, Samuel A.; Kamo, Sandra L.; Ferguson, Kurt M.; Macaulay, C. I.; Kelly, Amy E.

doi:10.1016/j.cretres.2015.04.010

Cited by 157 publications

(167 citation statements)

References 78 publications

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“…The laboratory preparation of material from Lozier Canyon, particularly from the Lower Eagle Ford Formation, has not been as successful as that of material from Iona-1 (Eldrett et al 2015) and Comstock West. Preservation at Lozier Canyon is often poor and many dinoflagellate cyst specimens are partially obscured by fine films of AOM, hindering confident identification at the species level.…”

Section: Resultsmentioning

confidence: 99%

“…The main palynological features are summarised in the assemblages column. Occurrences at Lozier Canyon of astronomically dated biostratigraphical events in the Iona-1 core (Eldrett et al 2015) are numbered in ascending order (see section 4 for discussion). Estimated ages in Iona-1 are: middle Cenomanian, P1 (96.…”

Section: Resultsmentioning

confidence: 99%

“…Iona-1 is located about 120 km SE of Lozier Canyon, at Sycamore Creek, near Del Rio. Uranium-lead (U-Pb) dates from individual zircons from 10 bentonite layers in Iona-1 provided geochronological constraints for astronomically tuned age models for individual bio-events (Eldrett et al 2015). The detailed dinoflagellate cyst stratigraphy of Iona-1 has been analysed from 195 samples, from the upper part of the Buda Formation, Eagle Ford Group and lower Austin Chalk Formation (Dodsworth, in Eldrett et al 2015).…”

Section: Background and Objectivesmentioning

confidence: 99%

“…Iona-1 was located in an intra-shelf basin, the Maverick Basin (Figure 1). Eldrett et al (2015) estimated that deposition of the Eagle Ford Group took place over approximately 7 million years, between ca. 97 and 90 Ma.…”

Section: Geological Settingmentioning

confidence: 99%

“…Sageman et al (2006). SB: Sabinas Basin; MB: Maverick Basin; ETB: East Texas Basin (adapted with permission from Ron Blakey and the Colorado Plateau Geosystems Inc. and Eldrett et al 2015).…”

Section: Background and Objectivesmentioning

confidence: 99%

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Palynostratigraphy and palaeoenvironments of the Eagle Ford Group (Upper Cretaceous) at the Lozier Canyon outcrop reference section, west Texas, USA

Dodsworth¹

2015

Palynology

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This study describes the detailed palynology of the Eagle Ford Group at Lozier Canyon, its principal outcrop reference section in west Texas. Prominent marine phytoplankton assemblages are consistent with a proposed depositional setting for Lozier Canyon on a submarine platform within the Cretaceous Western Interior Seaway (KWIS) of the USA. The Lower Eagle Ford Formation (middle to upper Cenomanian) was deposited under restricted marine conditions with oxygen-deficient, probably anoxic bottom waters, as indicated by the black, organic-rich (ca. 1 to > 6% total organic carbon) shale lithology. The formation comprises two fourth-order stratigraphical sequences, each showing sedimentary evidence of increasing water depth during deposition. Palynomorph assemblages from the sequences are dominated by green algal prasinophyte phycomata in the lower parts and peridinioid dinoflagellate cysts in the upper parts. The productivity of these marine phytoplankton groups may have been stimulated by availability of ammonium (prasinophytes) and nitrite (peridinioids) from upwelling, or vertical expansion of the oxygen-minimum zone. The transition from prasinophyte-to peridinioid-dominated assemblages may reflect elevation of the photic zone to a level less regularly encroached by deeper, ammonium-enriched waters of the denitrification zone. The overlying Upper Eagle Ford Formation (upper Cenomanian to upper Turonian or Coniacian) was deposited under deeper, relatively open marine conditions, as indicated by a decrease in organic carbon content and an increase in carbonate content. This is supported by the presence of diversified dinoflagellate cyst assemblages, including inter-regional (high-to mid-latitude) marker events; in the upper Cenomanian, base and acme Cyclonephelium compactum-membraniphorum, top consistent and frequent Litosphaeridium siphoniphorum, and top Adnatosphaeridium tutulosum; in the middle to upper Turonian, range bases of Heterosphaeridium difficile and Senoniasphaera rotundata. The stratigraphical resolution offered by palynology indicates potential application to wellsite 'geosteering' of commercial shale oil and shale gas wells drilled in the Eagle Ford Group.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Background and Objectivesmentioning

confidence: 99%

Section: Geological Settingmentioning

confidence: 99%

Section: Background and Objectivesmentioning

confidence: 99%

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Palynostratigraphy and palaeoenvironments of the Eagle Ford Group (Upper Cretaceous) at the Lozier Canyon outcrop reference section, west Texas, USA

Dodsworth¹

2015

Palynology

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Onset and demise of Cretaceous oceanic anoxic events: The coupling of surface and bottom oceanic processes in two pelagic basins of the western Tethys

et al. 2016

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The upper Albian-lower Turonian pelagic successions of the Tethys record processes acting during the onset, core, and recovery from perturbed conditions across oceanic anoxic event (OAE) 1d, OAE 2, and the mid-Cenomanian event I (MCE I) relative to intervening intervals. Five sections from Umbria-Marche and Belluno Basins (Italy) were analyzed at high resolution to assess processes in surface and deep waters. Recurrent facies stacking patterns (SP) and their associations record periods of bottom current activity coupled with surface changes in trophic level. Climate changes appear to have been influential on deep circulation dynamics. Under greenhouse conditions, vigorous bottom currents were arguably induced by warm and dense saline deep waters originated on tropical shelves in the Tethys and/or proto-Atlantic Ocean. Tractive facies postdating intermittent anoxia during OAE 1d and in the interval bracketed by MCE I and OAE 2 are indicative of feeble bottom currents, though capable of disrupting stratification and replenish deep water with oxygen. The major warming at the onset of OAE 2 might have enhanced the formation of warm salty waters, possibly producing local hiatuses at the base of the Bonarelli Level and winnowing at the seafloor. Hiatuses detected at the top of the Bonarelli Level possibly resulted from most effective bottom currents during the early Turonian thermal maximum. Times of minimal sediment displacement correlate with cooler climatic conditions and testify a different mechanism of deep water formation, as further suggested by a color change to reddish lithologies of the post-OAE 1d and post-OAE 2 intervals.

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Sedimentary Mercury Enrichments as a Marker for Submarine Large Igneous Province Volcanism? Evidence From the Mid‐Cenomanian Event and Oceanic Anoxic Event 2 (Late Cretaceous)

Scaife

Ruhl

Dickson

et al. 2017

Geochem Geophys Geosyst

104

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Oceanic Anoxic Event 2 (OAE 2), during the Cenomanian‐Turonian transition (∼94 Ma), was the largest perturbation of the global carbon cycle in the mid‐Cretaceous and can be recognized by a positive carbon‐isotope excursion in sedimentary strata. Although OAE 2 has been linked to large‐scale volcanism, several large igneous provinces (LIPs) were active at this time (e.g., Caribbean, High Arctic, Madagascan, Ontong‐Java) and little clear evidence links OAE 2 to a specific LIP. The Mid‐Cenomanian Event (MCE, ∼96 Ma), identified by a small, 1‰ positive carbon‐isotope excursion, is often referred to as a prelude to OAE 2. However, no underlying cause has yet been demonstrated and its relationship to OAE 2 is poorly constrained. Here we report sedimentary mercury (Hg) concentration data from four sites, three from the southern margin of the Western Interior Seaway and one from Demerara Rise, in the equatorial proto‐North Atlantic Ocean. We find that, in both areas, increases in mercury concentrations and Hg/TOC ratios coincide with the MCE and the OAE 2. However, the increases found in these sites are of a lower magnitude than those found in records of many other Mesozoic events, possibly characteristic of a marine rather than atmospheric dispersal of mercury for both events. Combined, the new mercury data presented here are consistent with an initial magmatic pulse at the time of the MCE, with a second, greater pulse at the onset of OAE 2, possibly related to the emplacement of LIPs in the Pacific Ocean and/or the High Arctic.

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An astronomically calibrated stratigraphy of the Cenomanian, Turonian and earliest Coniacian from the Cretaceous Western Interior Seaway, USA: Implications for global chronostratigraphy

Cited by 157 publications

References 78 publications

Palynostratigraphy and palaeoenvironments of the Eagle Ford Group (Upper Cretaceous) at the Lozier Canyon outcrop reference section, west Texas, USA

Palynostratigraphy and palaeoenvironments of the Eagle Ford Group (Upper Cretaceous) at the Lozier Canyon outcrop reference section, west Texas, USA

Onset and demise of Cretaceous oceanic anoxic events: The coupling of surface and bottom oceanic processes in two pelagic basins of the western Tethys

Sedimentary Mercury Enrichments as a Marker for Submarine Large Igneous Province Volcanism? Evidence From the Mid‐Cenomanian Event and Oceanic Anoxic Event 2 (Late Cretaceous)

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