scholarly journals Current synthesis of the penultimate icehouse and its imprint on the Upper Devonian through Permian stratigraphic record

2021 ◽  
pp. SP512-2021-124
Author(s):  
Isabel Patricia Montañez
Keyword(s):  
Ice Sheets ◽  
Late Paleozoic ◽  
Earth System ◽  
Low Latitude ◽  
New Techniques ◽  
Shallow Marine ◽  
Rigorous Testing ◽  
System Components ◽  
Stratigraphic Record ◽  
Age Constraints

AbstractIcehouses are the less common climate state on Earth, and thus it is notable that the longest lived (∼370 to 260 Ma) and possibly most extensive and intense of icehouse periods spanned the Carboniferous Period. Mid- to high-latitude glaciogenic deposits reveal a dynamic glaciation-deglaciation history with ice waxing and waning from multiple ice centers and possible transcontinental ice sheets during the apex of glaciation. New high-precision U-Pb ages confirm a hypothesized west-to-east progression of glaciation through the icehouse, but reveal that its demise occurred as a series of synchronous and widespread deglaciations. The dynamic glaciation history, along with repeated perturbations to Earth System components, are archived in the low-latitude stratigraphic record revealing similarities to the Cenozoic icehouse. Further assessing the phasing between climate, oceanographic, and biotic changes during the icehouse requires additional chronostratigraphic constraints. Astrochronology permits the deciphering of time, at high resolution, in the late Paleozoic record as has been demonstrated in deep- and quit-water deposits. Rigorous testing for astronomical forcing in low-latitude cyclothemic successions, which have a direct link to higher latitude glaciogenic records through inferred glacioeustasy, however, will require a comprehensive approach that integrates new techniques with further optimization and additional independent age constraints given challenges associated with shallow-marine to terrestrial records.

THE CONTRIBUTION OF VOLCANIC AEROSOLS TO EARTH SYSTEM BEHAVIOR IN THE LATE PALEOZOIC

2018 ◽  
Author(s):  
Gerilyn S. Soreghan ◽  
◽  
Michael J. Soreghan ◽  
Nicholas G. Heavens
Keyword(s):  
Late Paleozoic ◽  
Earth System ◽  
System Behavior ◽  
Volcanic Aerosols

LATE PALEOZOIC IRON FERTILIZATION FROM DUST ENHANCED SHALLOW MARINE PRIMARY PRODUCTIVITY

2019 ◽  
Author(s):  
Mehrdad Sardar Abadi ◽  
◽  
Jeremy D. Owens ◽  
Xiaolei Liu ◽  
Theodore R. Them ◽  
...  
Keyword(s):  
Primary Productivity ◽  
Late Paleozoic ◽  
Shallow Marine ◽  
Iron Fertilization ◽  
Marine Primary Productivity

Consistent retrieval of cloud/aerosol single scattering properties and surface reflectance

2021 ◽  
Author(s):  
Marta Luffarelli ◽  
Yves Govaerts
Keyword(s):  
Radiative Transfer ◽  
Optical Thickness ◽  
Solution Space ◽  
Single Scattering ◽  
Aerosol Optical Thickness ◽  
Radiative Transfer Model ◽  
Transfer Model ◽  
Surface Reflectance ◽  
Earth System ◽  
System Components

<p>The CISAR (Combined Inversion of Surface and AeRosols) algorithm is exploited in the framework of the ESA Aerosol Climate Change Initiatiave (CCI) project, aiming at providing a set of atmospheric (cloud and aerosol) and surface reflectance products derived from S3A/SLSTR observations using the same radiative transfer physics and assumptions. CISAR is an advance algorithm developed by Rayference originally designed for the retrieval of aerosol single scattering properties and surface reflectance from both geostationary and polar orbiting satellite observations.  It is based on the inversion of a fast radiative transfer model (FASTRE). The retrieval mechanism allows a continuous variation of the aerosol and cloud single scattering properties in the solution space.</p><p> </p><p>Traditionally, different approaches are exploited to retrieve the different Earth system components, which could lead to inconsistent data sets. The simultaneous retrieval of different atmospheric and surface variables over any type of surface (including bright surfaces and water bodies) with the same forward model and inversion scheme ensures the consistency among the retrieved Earth system components. Additionally, pixels located in the transition zone between pure clouds and pure aerosols are often discarded from both cloud and aerosol algorithms. This “twilight zone” can cover up to 30% of the globe. A consistent retrieval of both cloud and aerosol single scattering properties with the same algorithm could help filling this gap.</p><p> </p><p>The CISAR algorithm aims at overcoming the need of an external cloud mask, discriminating internally between aerosol and cloud properties. This approach helps reducing the overestimation of aerosol optical thickness in cloud contaminated pixels. The surface reflectance product is delivered both for cloud-free and cloudy observations.  </p><p> </p><p>Global maps obtained from the processing of S3A/SLSTR observations will be shown. The SLSTR/CISAR products over events such as, for instance, the Australian fire in the last months of 2019, will be discussed in terms of aerosol optical thickness, aerosol-cloud discrimination and fine/coarse mode fraction.</p>

scholarly journals Recent climatic, cryospheric, and hydrological changes over the interior of western Canada: a synthesis and review

2015 ◽  
Vol 12 (8) ◽  
pp. 8615-8674 ◽  
Author(s):  
C. M. DeBeer ◽  
H. S. Wheater ◽  
S. K. Carey ◽  
K. P. Chun
Keyword(s):  
Temporal Trends ◽  
Global Scale ◽  
Western Canada ◽  
Earth System ◽  
Predictive Capacity ◽  
Late 20Th Century ◽  
Cold Regions ◽  
Mountain Glaciers ◽  
System Components ◽  
Earth’S Climate

Abstract. It is well-established that the Earth's climate system has warmed significantly over the past several decades, and in association there have been widespread changes in various other Earth system components. This has been especially prevalent in the cold regions of the northern mid to high-latitudes. Examples of these changes can be found within the western and northern interior of Canada, a region that exemplifies the scientific and societal issues faced in many other similar parts of the world, and where impacts have global-scale consequences. This region has been the geographic focus of a large amount of previous research on changing climatic, cryospheric, and hydrological Earth system components in recent decades, while current initiatives such as the Changing Cold Regions Network (CCRN) seek to further develop the understanding and diagnosis of this change and hence improve predictive capacity. This paper provides an integrated review of the observed changes in these Earth system components and a concise and up-to-date regional picture of some of the temporal trends over the interior of western Canada since the mid or late-20th century. The focus is on air temperature, precipitation, seasonal snow cover, mountain glaciers, permafrost, freshwater ice cover, and river discharge. Important long-term observational networks and datasets are described, and qualitative linkages among the changing components are highlighted. Systematic warming and significant changes to precipitation, snow and ice regimes are unambiguous. However, integrated effects on streamflow are complex. It is argued that further diagnosis is required before predictions of future change can be made with confidence.

Maintaining Transactional Integrity in Long Running Workflow Services

2013 ◽  
pp. 135-164
Author(s):  
Stephan Reiff-Marganiec ◽  
Manar S. Ali
Keyword(s):  
Hierarchical Structure ◽  
Management System ◽  
Business Processes ◽  
Reactive System ◽  
Business Logic ◽  
Enterprise Integration ◽  
New Techniques ◽  
Notable Feature ◽  
System Components ◽  
System Controller

This chapter presents a framework to provide autonomous handling of long running transactions based on dependencies which are derived from the workflow. Business Processes naturally involve long running activities and require transactional behaviour across them. This framework presents a solution for forward recovery from errors by automatic application of compensation to executing instances of workflows. The mechanism is based on propagation of failures through a recursive hierarchical structure of transaction components (nodes and execution paths). The authors discuss a transaction management system that is implemented as a reactive system controller, where system components change their states based on rules in response to triggering of events, such as activation, failure, force-fail, completion, or compensation events. One notable feature of the model is the distinction of vital and non-vital components, allowing the process designer to express the cruciality of activities in the workflow with respect to the business logic. Another novel feature is that in addition to dependencies arising from the structure of the workflow, the approach also permits the workflow designer to specify additional dependencies which will also be enforced. Thus, the authors introduce new techniques and architectures supporting enterprise integration solutions that cater to the dynamics of business needs. The approach is implemented through workflow actions executed by services and allows management of faults through a policy-driven framework.

scholarly journals Glaciomarine sequence stratigraphy in the Mississippian Río Blanco Basin, Argentina, southwestern Gondwana. Basin analysis and palaeoclimatic implications for the Late Paleozoic Ice Age during the Tournaisian.

2020 ◽  
Vol 177 (6) ◽  
pp. 1107-1128 ◽  
Author(s):  
Miguel Ezpeleta ◽  
Juan José Rustán ◽  
Diego Balseiro ◽  
Federico Miguel Dávila ◽  
Juan Andrés Dahlquist ◽  
...  
Keyword(s):  
Compositional Analysis ◽  
Ice Age ◽  
Late Paleozoic ◽  
Provenance Analysis ◽  
Glacial Ice ◽  
Content Type ◽  
Late Paleozoic Ice Age ◽  
Glacial Stage ◽  
Supplementary Material ◽  
Age Constraints

The Late Paleozoic Ice Age (LPIA) has been well recorded in the uppermost Mississippian–Pennsylvanian of Gondwana. Nevertheless, little is known about the temporal and geographic dynamics, particularly during the early Mississippian. We report on exceptional Tournaisian glaciomarine stratigraphic sections from central Argentina (Río Blanco Basin). Encompassing c. 1400 m, these successions contain conspicuous glacigenic strata with age constraints provided by palaeontological data and U/Pb detrital zircon age spectra. A variety of marine, glaciomarine and fan-deltaic environments indicate relative sea-level variations mainly associated with tectonism and repetitive cycles of glacial activity. Provenance analysis indicates a source from the Sierras Pampeanas basement located to the east. Fifteen sequences were grouped into three depositional models: (1) Transgressive Systems Tracts (TST) to Highstand Systems Tracts (HST) sequences unaffected by glacial ice; (2) Lowstand Systems Tracts (LST) to TST and then to HST with glacial influence; and (3) non-glacial Falling-Stage Systems Tracts (FSST) to TST and HST. The glacial evidence indicates that the oldest Mississippian glacial stage of the LPIA in southwestern Gondwana is constrained to the middle Tournaisian. In contrast with previous descriptions of Gondwanan coeval glacial records, our sequence analysis confirms complex hierarchical climate variability, rather than a single episode of ice advance and retreat.Supplementary material: Detailed stratigraphic sections, palaeocurrents and compositional analysis and U/Pb detrital Zr methodology and data are available at: https://doi.org/10.6084/m9.figshare.c.5011424

Asynchronous trilobite extinctions at the early to middle Cambrian transition

Geology ◽  
2020 ◽  
Vol 48 (5) ◽  
pp. 441-445 ◽  
Author(s):  
F.A. Sundberg ◽  
K.E. Karlstrom ◽  
G. Geyer ◽  
J.R. Foster ◽  
J.W. Hagadorn ◽  
...  
Keyword(s):  
Critical Time ◽  
Data Sets ◽  
Early Cambrian ◽  
Earth System ◽  
Middle Cambrian ◽  
West Gondwana ◽  
Paleoclimatic Data ◽  
First Time ◽  
Age Constraints ◽  
Prior Models

Abstract Trilobites appeared and diversified rapidly in the Cambrian, but it is debated as to whether their radiations and extinctions were globally synchronous or geographically restricted and diachronous. The end of the early Cambrian is a classic example—it has traditionally been defined by the extinction of olenellid and redlichiid trilobites and the appearance of paradoxidid trilobites. Here we integrate the global biostratigraphy of these three trilobite groups with high-precision tuff and tandem detrital zircon U-Pb age constraints to falsify prior models for global synchronicity of these events. For the first time, we demonstrate that olenellid trilobites in Laurentia went extinct at least 3 Ma after the first appearance of paradoxidids in Avalonia and West Gondwana (ca. 509 Ma). They also disappeared before the extinction of redlichiids and prior to the base of the Miaolingian at ca. 506 Ma in South China. This indicates that these three trilobite groups (paradoxidids, olenellids, and redlichiids) and their associated biotas overlapped in time for nearly 40% of Cambrian Epoch 2, Age 4. Implications of this chronological overlap are: (1) trilobite transitions were progressive and geographically mediated rather than globally synchronous; and (2) paleontological databases underestimate the diversity of the early Cambrian. This ∼3 Ma diachroneity, at a critical time in the early evolution of animals, also impacts chemostratigraphic and paleoclimatic data sets that are tied to trilobite biostratigraphy and that collectively underpin our understanding of the Cambrian Earth system.

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