Evidences of Widespread Cretaceous Deep Weathering and Its Consequences: A Review

Bata, Timothy

doi:10.5539/esr.v5n2p69

Cited by 14 publications

(8 citation statements)

References 81 publications

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“…93,-0.90, -087, -0.82, -0.72, -0.72 and -0.58; respectively). Thus, U contents in the study phosphatic rocks were probably associated with anoxic sediments more than associated with the heavy metals and trace elements during the chemical weathering [33][34][35] under oxic conditions [36]. Thus, anoxic sediments are much more enriched in U than oxic ones [37].…”

Section: Distribution Of Uraniummentioning

confidence: 86%

P2O5 – F- U Characterization and Depositional Environment of Phosphatic Rocks for the Duwi Formation, Qussier- Safaga Region, Red Sea Coast, Egypt.

2019

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T HE Duwi Formation in Qusseir-Safaga region is conformably overlain by the Qusseir variegated shales and underlain by the Dakhla shales. The studied phosphatic rocks in the Duwi Formation, is an attractive rock unit for it's enrichment in heavy metals and U content.Mineralogically, phosphatic rocks in the Duwi Formation are mainly composed mainly of fluorapatite, in addition to minor occurrence of calcite, dolomite, gypsum, quartz, and pyrite. Geochemical data reveal that the rocks of the Duwi Formation were deposited under anoxic environments. The present study used the statistical result of the interrelation between P 2 O 5 , F and U concentrations on Egyptian phosphate samples and compared to the measured data. Uranium mostly occurs in an oxidized U 6+ state. It could be fixed with the phosphatic ion, forming secondary uranium phosphate minerals such as phosphuranylite and belovite in Qusseir region. In addition to Uranyl phosphates, uranium minerals in Safaga region contain also Uranyl carbonates and Uranyl sulfates, which had been attributed to the post-depositional U enrichment. The chemical data and index show that the phosphatic rocks in Safaga region are more enriched in the majority trace and rare earth elements, and are subjected to high chemical weathering than those in Qusseir region.

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Section: Distribution Of Uraniummentioning

confidence: 86%

P2O5 – F- U Characterization and Depositional Environment of Phosphatic Rocks for the Duwi Formation, Qussier- Safaga Region, Red Sea Coast, Egypt.

2019

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“…In the Late Cretaceous greenhouse climate (Arthur et al, 1985;Hay, 2008), tropical weathering was more prevalent compared to the present-day (Widdowson, 2007;Craggs et al, 2012;Bata et al, 2016). Moreover, the Cretaceous land surfaces were characterized by shallow relief (Hay et al, 2019).…”

Section: Significance Of the Ferruginous Proxy Signaturementioning

confidence: 99%

Oxygen minimum zone-type biogeochemical cycling in the Cenomanian-Turonian Proto-North Atlantic across Oceanic Anoxic Event 2

Scholz

Beil

Flögel

et al. 2019

Earth and Planetary Science Letters

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Oceanic Anoxic Events (OAEs) in Earth's history are regarded as analogues for current and future ocean deoxygenation, potentially providing information on its pacing and internal dynamics. In order to predict the Earth system's response to changes in greenhouse gas concentrations and radiative forcing, a sound understanding of how biogeochemical cycling differs in modern and ancient marine environments is required. Here, we report proxy records for iron (Fe), sulfur and nitrogen cycling in the Tarfaya upwelling system in the Cretaceous Proto-North Atlantic before, during and after OAE2 (~93 Ma). We apply a novel quantitative approach to sedimentary Fe speciation, which takes into account the influence of terrigenous weathering and sedimentation as well as authigenic Fe (nonterrigenous, precipitated onsite) rain rates on Fe-based paleo-redox proxies. Generally elevated ratios of reactive Fe (i.e., bound to oxide, carbonate and sulfide minerals) to total Fe (Fe HR /Fe T ) throughout the 5 million year record are attributed to transport-limited chemical weathering under 2 greenhouse climate conditions. Trace metal and nitrogen isotope systematics indicate a step-wise transition from oxic to nitrogenous to euxinic conditions over several million years prior to OAE2.Taking into consideration the low terrigenous sedimentation rates in the Tarfaya Basin, we demonstrate that highly elevated Fe HR /Fe T from the mid-Cenomanian through OAE2 were generated with a relatively small flux of additional authigenic Fe. Evaluation of mass accumulation rates of reactive Fe in conjunction with the extent of pyritization of reactive Fe reveals that authigenic Fe and sulfide precipitation rates in the Tarfaya Basin were similar to those in modern upwelling systems.Because of a smaller seawater nitrate inventory, however, chemolithoautotrophic sulfide oxidation with nitrate was less efficient in preventing hydrogen sulfide release into the water column. As terrigenous weathering and sediment flux determine how much authigenic Fe is required to generate an anoxic euxinic or ferruginous proxy signature, we emphasize that both have to be taken into account when interpreting Fe-based paleo-redox proxies.

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“…The most recent paleobiogeographical Sebecia history is represented by Node 35 (BA area) and is a result of dispersion from B area to BA area followed by an isolator event in Cenonian-Turonian stages. This event with isolated species 9 and 10 (Node 35) is a vicariance confirmed by all three analysis (BBM, S-DIVA and BPA) and can be associated with a moment of marine transgression in Iullemmeden Basin (Bata, 2016;Moody, 1997). BBM analysis reconstruction found Iullemmeden Basin (area B) with a high probability (47.49%) to be the ancestral area for Notosuchia (Node 52, Fig.…”

Section: Discussionmentioning

confidence: 56%

Paleobiogeography of Cretaceous South American Mesoeucrocodylia: Contribution to the Knowledege of Biogeographical History of Gondwana and Laurasia

Geroto¹

2019

Preprint

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Aim: Despite Mesoeucrocodylia been the most expressive faunal elements in outcrops of Gondwana, with special attention to South American basin like Bauru Group in Parana Basin and Neuquén Group in Neuquén Basin the biogeographical studies has been almost descriptive. These studies point the hypothesis that vicariance, specially the event of breakup of Gondwana, occupy a main role in speciation and diversification of Mesoeucrocodylia in Cretaceous. The present research investigates the possibility of this hypothesis been true use two complementary methods of biogeographic analysis a priori.Location: The studied reach the sedimentary basins for Gondwana and Laurassa when Mesoeucrocodylia fossils are found (South America, Africa and Eurasia continents)Methods: Brook Parsimony Analysis, with use maximum parsimony, Bayesian Binary Method for Ancestral State, a maximum like hood method to large data set, and S-DIVA to test the vicariance hypothesis. The area cladograms area time calibrating used the Temporal Calibrating GACs.Results: Allow reconstruct the ancestral area to the ancestral lineages and track the origin of “Gondwanasuchia” mesoeucrocodylian to African portion, posterior dispersion to South America. Notosuchia had an almost South American history with only peripheral ancestral reach Africa and Peirosauridae divide in two lineages, Peirosaurinae developed almost in Africa and reach South America in Early Cretaceous and Pepesuchinae an endemic South American lineage. Main Conclusions: Dispersal, not vicariance, take the main role in the diversification of the Mesoeucrocodylia during the Cretaceous. Three migration routes between drain channels take place in Early Cretaceous, one of Peirosaurinae from Araripe Basin to southern portion of South America, another from Pepesuchinae to Bauru Group and the last one of Araripesuchidae from Neuquén Basin do Araripe Basin. With the isolation of Bauru Group in Santonian a series of sympatric speciation take place in Mesoeucrocodylia lineages and other groups like titanosaurids. These sympatric events need future investigations.

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Evidences of Widespread Cretaceous Deep Weathering and Its Consequences: A Review

Cited by 14 publications

References 81 publications

P2O5 – F- U Characterization and Depositional Environment of Phosphatic Rocks for the Duwi Formation, Qussier- Safaga Region, Red Sea Coast, Egypt.

P2O5 – F- U Characterization and Depositional Environment of Phosphatic Rocks for the Duwi Formation, Qussier- Safaga Region, Red Sea Coast, Egypt.

Oxygen minimum zone-type biogeochemical cycling in the Cenomanian-Turonian Proto-North Atlantic across Oceanic Anoxic Event 2

Paleobiogeography of Cretaceous South American Mesoeucrocodylia: Contribution to the Knowledege of Biogeographical History of Gondwana and Laurasia

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