Reevaluation of the timing and extent of late Paleozoic glaciation in Gondwana: Role of the Transantarctic Mountains

Geology ◽  
2003 ◽  
Vol 31 (11) ◽  
pp. 977 ◽  
Author(s):  
John L. Isbell ◽  
Paul A. Lenaker ◽  
Rosemary A. Askin ◽  
Molly F. Miller ◽  
Loren E. Babcock
Keyword(s):  
Late Paleozoic ◽  
Transantarctic Mountains

Evidence of oribatid mite detritivory in Antarctica during the late Paleozoic and Mesozoic

2004 ◽  
Vol 78 (6) ◽  
pp. 1146-1153 ◽  
Author(s):  
Derek W. Kellogg ◽  
Edith L. Taylor
Keyword(s):  
Fossil Record ◽  
Oribatid Mite ◽  
Late Paleozoic ◽  
Transantarctic Mountains ◽  
Animal Interaction ◽  
Wood Boring

Despite their importance in breaking down lignified tissue today, much is still unknown about the role of mites in the fossil record, especially with reference to the Paleozoic–Mesozoic transition. This study examines permineralized peat from three localities in the central Transantarctic Mountains, ranging in age from Permian to Jurassic, for evidence of diversity and abundance of wood-boring mites. Evidence of mites, in the form of coprolites and tunnels in wood and other tissues, was found at all three localities; the Triassic site included more than 10 times as many wood borings as the Permian site. Our results supplement prior evidence of wood-boring mites during the Mesozoic and thereby fill in the known geologic range of this plant/animal interaction.

Contribution a l'etude tectonique de la presqu'ile de Brogger (Spitsberg)

1966 ◽  
Vol S7-VIII (4) ◽  
pp. 560-566 ◽  
Author(s):  
Lucien Barbaroux
Keyword(s):  
Late Carboniferous ◽  
Late Paleozoic ◽  
Metamorphic Complex

Abstract New observations on the Brogger peninsula (Spitsbergen) show that the Hecla Hoek (Caledonide) geosynclinal metamorphic complex, reactivated by successive orogenies, overlaps Paleozoic and Cenozoic sedimentary formations in a northwest direction along a continuous front. The role of northwest-southeast-trending deformation in the Hercynian (late Paleozoic) and north-south deformation in the Tertiary assume greater importance than was heretofore accorded them. The existence of an Erzgebirgian (late Carboniferous) and a Saalian (mid-Permian) phase of Paleozoic orogeny can be shown.

scholarly journals Influence of temporally varying weatherability on CO<sub>2</sub>–climate coupling and ecosystem change in the late Paleozoic

2020 ◽  
Author(s):  
Jon D. Richey ◽  
Isabel P. Montañez ◽  
Yves Goddéris ◽  
Cindy V. Looy ◽  
Neil P. Griffis ◽  
...  
Keyword(s):  
Steady State ◽  
Ice Age ◽  
Secular Change ◽  
Ecosystem Change ◽  
Late Paleozoic ◽  
Relative Role ◽  
C Cycle ◽  
Ecosystem Perturbation ◽  
Atmospheric Pco2

Abstract. Earth's penultimate icehouse, the Late Paleozoic Ice Age (LPIA), was a time of dynamic glaciation and repeated ecosystem perturbation, under conditions of substantial variability in atmospheric pCO2 and O2. Improved constraints on the evolution of atmospheric pCO2 and O2 : CO2 during the LPIA and its subsequent demise to permanent greenhouse conditions is crucial for better understanding the nature of linkages between atmospheric composition, climate, and ecosystem perturbation during this time. We present a new and age-recalibrated pCO2 reconstruction for a 40-Myr interval (~313 to 273 Ma) of the late Paleozoic that (1) confirms a previously hypothesized strong CO2-glaciation linkage, (2) documents synchroneity between major pCO2 and O2 : CO2 changes and compositional turnovers in terrestrial and marine ecosystems, (3) lends support for a modeled progressive decrease in the CO2 threshold for initiation of continental ice sheets during the LPIA, and (4) indicates a likely role of CO2 and O2 : CO2 thresholds in floral ecologic turnovers. Modeling of the relative role of CO2 sinks and sources, active during the LPIA and its demise, on steady-state pCO2 using an intermediate complexity climate-C cycle model (GEOCLIM) and comparison to the new multi-proxy CO2 record provides new insight into the relative influences of the uplift of the Central Pangaean Mountains, intensifying aridification, and increasing mafic rock to-granite rock ratio of outcropping rocks on the global efficiency of CO2 consumption and secular change in steady-state pCO2 through the late Paleozoic.

scholarly journals The Role of Lithospheric Flexure in the Landscape Evolution of the Wilkes Subglacial Basin and Transantarctic Mountains, East Antarctica

2019 ◽  
Vol 124 (3) ◽  
pp. 812-829 ◽  
Author(s):  
Guy J. G. Paxman ◽  
Stewart S. R. Jamieson ◽  
Fausto Ferraccioli ◽  
Michael J. Bentley ◽  
Neil Ross ◽  
...  
Keyword(s):  
Landscape Evolution ◽  
East Antarctica ◽  
Lithospheric Flexure ◽  
Transantarctic Mountains

scholarly journals Glaciation, erosion and the evolution of the Transantarctic Mountains, Antarctica

1996 ◽  
Vol 23 ◽  
pp. 303-308 ◽  
Author(s):  
Andrew Kerr ◽  
Alan Gilchrist
Keyword(s):  
Tectonic Evolution ◽  
Flexural Rigidity ◽  
High Amplitude ◽  
Insufficient Data ◽  
Glacial Erosion ◽  
Denudation Rates ◽  
Modelling Studies ◽  
Glacial Processes ◽  
Transantarctic Mountains

Modelling studies of the tectonic evolution of the Transantarctic Mountains in Antarctica have drawn differing conclusions as to the primary mechanisms involved. None has considered the role of the East Antarctic ice sheet in detail. We use a denudation—flexural model to examine the isostatic response of the continental margin to glacial erosion to determine whether glacial processes have played a role in forcing mountain uplift. The conclusion is that, although there are insufficient data formally to delimit the role of glacial erosion, available geophysical and geomorphological data are not inconsistent with the results of the differential denudation model, providing certain conditions are met. These results indicate that the current topography of the Transantarctic Mountains can be simulated, in part, from the isostatic response of the lithosphere to glacial erosion. The short wavelength and high amplitude of the Transantarctic Mountains do not require a low flexural rigidity in the unrated lithosphere, provided there is a fast escarpment retreat from the rift hinge, high escarpment denudation rates and a large differential in denudation between the coastal zone and the interior.

scholarly journals The role of environment in the diversity and evolutionary turnover rates of the Foraminiferida

1992 ◽  
Vol 6 ◽  
pp. 278-278 ◽  
Author(s):  
S.W. Starratt
Keyword(s):  
Shallow Water ◽  
Sea Level ◽  
Deep Water ◽  
Taxonomic Diversity ◽  
Late Paleozoic ◽  
Ecological Niches ◽  
Time Interval ◽  
Turnover Rates ◽  
Extinction Event

Taxonomic databases are important tools in the study of faunal diversity and evolution. The usefulness of the inferences drawn from these databases is diminished when the role of environment is not considered. Analysis of the foraminiferal database at the genus and family levels is used to demonstrate the effect of water depth on presumed changes in taxonomic diversity and evolutionary turnover rates.This paleoenvironmental effect is particularly noticeable when foraminiferal faunas of the late Paleozoic and the Mesozoic and Cenozoic intervals are compared. The late Paleozoic fauna is dominated by the Fusulinina and shallow-water (0–200 m) Textularuna. Standing diversity fluctuates greatly, and evolutionary turnover is high. This reflects short-term fluctuations in sea level which led to the rapid formation and destruction of narrow ecological niches. Evolutionary turnover appears to be related to reef growth during this time. This trend may also reflect an increased number of k-selected specialists which serve as proxy indicators for a slow-circulating oligotrophic ocean system. Shallow-water taxa may also be predisposed to extinction due to their reliance on symbiotic algae. The extinction event at the end of the Permian resulted in the loss of almost 70% of the standing generic diversity. This included the complete loss of the Fusulinina as well as a number of shallow-water textularids. Cohort survivorship curves are steep and taxon ages short during this time.The diversity increase over the past 245 million years has largely been due to the addition of deep-water (200-10,000 m) taxa. This was particularly true during the Late Cretaceous and early Eocene, and may reflect the relatively high eustatic sea level during those intervals. The relationship between reef development and evolutionary turnover rates is less clear during this time interval. Although the extinction event that marked the end of the Cretaceous resulted in a greater loss in absolute taxonomic diversity than occurred at the end of the Permian, the relative loss in generic diversity was only about 21% due to the large number of deep-water taxa. When the entire fauna is considered, cohort survivorship curves are less steep and taxon ages are longer than in the late Paleozoic, but when only the shallow-water taxa are considered, the results are similar to those for the late Paleozoic.

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