Sedimentation across the Paraburdoo spherule layer: Implications for the Neoarchean Earth system

2021 ◽  
Author(s):  
Katrina S. Souders ◽  
Alexandra K. Davatzes ◽  
Brady A. Ziegler ◽  
Steven Goderis ◽  
Thomas Déhais ◽  
...  
Keyword(s):  
Global Change ◽  
Water Column ◽  
Deep Water ◽  
Atmospheric Composition ◽  
Earth System ◽  
High Co2 ◽  
Tectonic Regime ◽  
Great Oxidation Event ◽  
Global Oceans

ABSTRACT Large bolide impacts in the Phanerozoic produced global change identifiable in the postimpact sediments. Aside from a few isolated examples, however, evidence of postimpact change associated with Precambrian impacts is sparse. This study used the Neoarchean Paraburdoo spherule layer as a case study to search for impact-induced change in the sediments above the spherule layer. We found possible minor sedimentary changes that may have been due to either a disturbance by bottom currents or changing diagenetic conditions. Contrary to the trends found with several post–Great Oxidation Event large bolide impacts, we found no evidence of shifts in tectonic regime, sediment weathering and deposition, or paleoenvironment induced by the Paraburdoo spherule layer impact, for which the impactor is estimated to have been approximately three times larger than the Cretaceous–Paleogene bolide. This lack of a clear signal of climatic shift may be due to one or more mechanisms. Either the Paraburdoo spherule layer’s deposition in several-hundred-meter-deep water within the Hamersley Basin of Western Australia was too deep to accumulate and record observable changes, or the Neoarchean’s high-CO2 atmospheric composition acted as a threshold below which the introduction of more impact-produced gases would not have produced the expected climatic and weathering changes. We also report minor traces of elevated iron and arsenic concentrations in the sediments immediately above the Paraburdoo spherule layer, consistent with trends observed above other distal impact deposits, as well as distinctive layers of hematite nodules bracketing the spherule layer. These geochemical changes may record ocean overturn of the Neoarchean stratified water column, which brought slightly oxygenated waters to depth, consistent with the observation of tsunami deposits in shallower impact deposits and/or heating of the global oceans by tens to hundreds of degrees Celsius in the wake of the Paraburdoo spherule layer impact. Either or both of these mechanisms in addition to impact-induced shallow-water ocean evaporation may also have caused a massive die-off of microbes, which also would have produced a postimpact increase in iron and arsenic concentrations.

Why Simulate?

1991 ◽  
Author(s):  
James C. G. Walker
Keyword(s):  
Global Change ◽  
Trace Element Composition ◽  
Atmospheric Composition ◽  
Earth System ◽  
Earth System Science ◽  
System Science ◽  
The Past ◽  
The Earth ◽  
The Future ◽  
Systems Simulation

Our world is a product of complex interactions among atmosphere, ocean, rocks, and life that Earth system science seeks to understand. Earth system science deals with such properties of the environment as composition and climate and populations and the ways in which they affect one another. It also concerns how these interactions caused environmental properties to change in the past and how they may change in the future. The Earth system can be studied quantitatively because its properties can be represented by numbers. At present, however, most of the numbers in Earth system science are observational rather than theoretical, and so our description of the Earth system's objective properties is much more complete than our quantitative understanding of how the system works. Quantitative theoretical understanding grows out of a simulation of the system or parts of the system and numerical experimentation with simulated systems. Simulation experiments can answer questions like What is the effect of this feature? or What would happen in that situation? Simulation also gives meaning to observations by showing how they may be related. As an illustration, consider that area of Earth system science known as global change. There is now an unambiguous observational record of global change in many important areas of the environment. For elements of climate and atmospheric composition this record is based on direct measurement over periods of a decade to a century. For other environmental variables, particularly those related to the composition of the ocean, the record of change consists of measurements of isotopic or trace-element composition of sediments deposited over millions of years. This evidence of global change is profoundly affecting our view of what the future holds in store for us and what options exist. It should also influence our understanding of how the interaction of biota and environment has changed the course of Earth history. But despite the importance of global change to our prospects for the future and our understanding of the past, the mechanisms of change are little understood. There are many speculative suggestions about the causes of change but few quantitative and convincing tests of these suggestions.

scholarly journals Stratigraphic and tectonic control of deep-water scarp accumulation in Paleogene synorogenic basins: a case study of the Súľov Conglomerates (Middle Váh Valley, Western Carpathians)

2017 ◽  
Vol 68 (5) ◽  
pp. 403-418 ◽  
Author(s):  
Ján Soták ◽  
Zuzana Pulišová ◽  
Dušan Plašienka ◽  
Viera Šimonová
Keyword(s):  
Deep Water ◽  
Fault Scarp ◽  
Submarine Landslides ◽  
Orogenic Wedge ◽  
Calcite Veins ◽  
Tectonic Erosion ◽  
Mass Flow Deposits ◽  
Miocene Tectonics ◽  
Mass Transport Deposits

Abstract The Súľov Conglomerates represent mass-transport deposits of the Súľov-Domaniža Basin. Their lithosomes are intercalated by claystones of late Thanetian (Zones P3 - P4), early Ypresian (Zones P5 - E2) and late Ypresian to early Lutetian (Zones E5 - E9) age. Claystone interbeds contain rich planktonic and agglutinated microfauna, implying deep-water environments of gravity-flow deposition. The basin was supplied by continental margin deposystems, and filled with submarine landslides, fault-scarp breccias, base-of-slope aprons, debris-flow lobes and distal fans of debrite and turbidite deposits. Synsedimentary tectonics of the Súľov-Domaniža Basin started in the late Thanetian - early Ypresian by normal faulting and disintegration of the orogenic wedge margin. Fault-related fissures were filled by carbonate bedrock breccias and banded crystalline calcite veins (onyxites). The subsidence accelerated during the Ypresian and early Lutetian by gravitational collapse and subcrustal tectonic erosion of the CWC plate. The basin subsided to lower bathyal up to abyssal depth along with downslope accumulation of mass-flow deposits. Tectonic inversion of the basin resulted from the Oligocene - early Miocene transpression (σ1 rotated from NW-SE to NNW-SSE), which changed to a transpressional regime during the Middle Miocene (σ1 rotated from NNE-SSW to NE-SW). Late Miocene tectonics were dominated by an extensional regime with σ3 axis in NNW-SSE orientation.

Limitations of Corrosion Resistant Alloy in High CO2 Gas Production Systems: A Case Study

2021 ◽  
Author(s):  
Jorge Rodriguez ◽  
Susana Gómez ◽  
Ngoc Tran Dinh ◽  
Giovanni Ortuño ◽  
Narendra Borole
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
High Pressure ◽  
Stainless Steel ◽  
Carbon Steel ◽  
Material Selection ◽  
Dynamic Modelling ◽  
General Corrosion ◽  
High Co2

Abstract The paper presents the application of a holistic approach to corrosion prediction that overcomes classical pitfalls in corrosion testing and modelling at high pressure, high temperature and high CO2 conditions. Thermodynamic modelling of field and lab conditions allows for more accurate predictions by a novel CO2/H2S general corrosion model validated by laboratory tests. In the proposed workflow, autoclave tests at high pressure and temperature are designed after modeling corrosion in a rigorous thermodynamic framework including fluid-dynamic modelling; the modeled steps include preparation, gas loading and heating of fluid samples at high CO2 concentration, and high flow velocities. An autoclave setup is proposed and validated to simultaneously test different conditions. Corrosion rates are extrapolated to compute service life of the materials and guide material selection. The results from the model and tests extend the application of selected stainless steel grade beyond the threshold conditions calculated by simplistic models and guidelines. Consideration of fugacities and true aqueous compositions allows for accurate thermodynamic representation of field conditions. Computation by rigorous fluid dynamics of shear stress, multiphase flow and heat transfer effects inside completion geometry lead to a proper interpretation of corrosion mechanisms and models to apply. In the case study used to showcase the workflow, conventional stainless steel is validated for most of the tubing. It is observed that some sections of the system in static condition are not exposed to liquid water, allowing for safe use of carbon steel, while as for other critical parts, more noble materials are deemed necessary. Harsh environments pose a challenge to the application of conventional steel materials. The workflow applied to the case study allows accurate representation and application of materials in its application limit region, allowing for safe use of carbon steel or less noble stainless steels in those areas of the completion where corrosion is limited by multiphase fluid-dynamics, heat transfer or the both. The approximation is validated for real case study under high CO2 content, and is considered also valid in the transportation of higher amounts of CO2, for example, in CCUS activities.

Integrated Reservoir Petrophysical Characterization and 3D Modeling: a Deep-Water Turbidite Reservoir Case Study

2008 ◽  
Author(s):  
Livio Ruvo ◽  
Mirko Calderoni ◽  
Marco Cesaro ◽  
Franco Fonnesu ◽  
Ilario Franco ◽  
...  
Keyword(s):  
Deep Water ◽  
3D Modeling
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