Provenance of late Paleozoic glacial/post-glacial deposits in the eastern Chaco-Paraná Basin, Uruguay and southernmost Paraná Basin, Brazil

2020 ◽  
pp. 102989
Author(s):  
Nicholas D. Fedorchuk ◽  
Neil P. Griffis ◽  
John L. Isbell ◽  
César Goso ◽  
Eduardo L.M. Rosa ◽  
...  
Keyword(s):  
Late Paleozoic ◽  
Glacial Deposits ◽  
Paraná Basin ◽  
Parana Basin

scholarly journals A new Xenacanthiformes shark (Chondrichthyes, Elasmobranchii) from the Late Paleozoic Rio do Rasto Formation (Paraná Basin), Southern Brazil

2014 ◽  
Vol 86 (1) ◽  
pp. 135-145 ◽  
Author(s):  
VICTOR E. PAULIV ◽  
ELISEU V. DIAS ◽  
FERNANDO A. SEDOR ◽  
ANA MARIA RIBEIRO
Keyword(s):  
New Species ◽  
Longitudinal Section ◽  
Optical Microscope ◽  
Late Paleozoic ◽  
Southern Brazil ◽  
Fossil Assemblage ◽  
Transversal Section ◽  
Paraná Basin ◽  
Parana Basin ◽  
A New Species

The Brazilian records on Xenacanthiformes include teeth and cephalic spines from the Parnaíba, Amazonas and Paraná basins. This work describes a new species of Xenacanthidae, collected in an outcrop of Serrinha Member of Rio do Rasto Formation (Wordian to Wuchiapingian), Paraná Basin, municipality of Jacarezinho, State of Paraná. The teeth of the new species are two or three-cuspidated and the aboral surface show a smooth concavity and one rounded basal tubercle. The coronal surface presents one semi-spherical and subcircular coronal button, and also two lateral main cusps and one central (when present) with less than one fifth of the size of the lateral cusps in the labial portion. The lateral cusps are asymmetric or symmetric, rounded in transversal section, lanceolate in longitudinal section, devoid of lateral carinae and lateral serrations, and with few smooth cristae of enameloid. In optical microscope the teeth show a trabecular dentine (osteodentine) base, while the cusps are composed by orthodentine, and the pulp cavities are non-obliterated by trabecular dentine. The fossil assemblage in the same stratigraphical level and in the whole Rio do Rasto Formation indicates another freshwater record for xenacanthid sharks.

scholarly journals Coupled stratigraphic and U-Pb zircon age constraints on the late Paleozoic icehouse-to-greenhouse turnover in south-central Gondwana

Geology ◽  
2019 ◽  
Vol 47 (12) ◽  
pp. 1146-1150 ◽  
Author(s):  
Neil Patrick Griffis ◽  
Isabel Patricia Montañez ◽  
Roland Mundil ◽  
Jon Richey ◽  
John Isbell ◽  
...  
Keyword(s):  
Ice Age ◽  
Late Paleozoic ◽  
Karoo Basin ◽  
Base Level ◽  
South Central ◽  
Paraná Basin ◽  
Forcing Mechanisms ◽  
Sequence Boundaries ◽  
Parana Basin ◽  
Order Sequence

Abstract The demise of the Late Paleozoic Ice Age has been hypothesized as diachronous, occurring first in western South America and progressing eastward across Africa and culminating in Australia over an ∼60 m.y. period, suggesting tectonic forcing mechanisms that operate on time scales of 106 yr or longer. We test this diachronous deglaciation hypothesis for southwestern and south-central Gondwana with new single crystal U-Pb zircon chemical abrasion thermal ionizing mass spectrometry (CA-TIMS) ages from volcaniclastic deposits in the Paraná (Brazil) and Karoo (South Africa) Basins that span the terminal deglaciation through the early postglacial period. Intrabasinal stratigraphic correlations permitted by the new high-resolution radioisotope ages indicate that deglaciation across the S to SE Paraná Basin was synchronous, with glaciation constrained to the Carboniferous. Cross-basin correlation reveals two additional glacial-deglacial cycles in the Karoo Basin after the terminal deglaciation in the Paraná Basin. South African glaciations were penecontemporaneous (within U-Pb age uncertainties) with third-order sequence boundaries (i.e., inferred base-level falls) in the Paraná Basin. Synchroneity between early Permian glacial-deglacial events in southwestern to south-central Gondwana and pCO2 fluctuations suggest a primary CO2 control on ice thresholds. The occurrence of renewed glaciation in the Karoo Basin, after terminal deglaciation in the Paraná Basin, reflects the secondary influences of regional paleogeography, topography, and moisture sources.

Late Paleozoic Ice-Age rhythmites in the southernmost Paraná Basin: A sedimentological and paleoenvironmental analysis

2020 ◽  
Vol 90 (8) ◽  
pp. 969-979 ◽  
Author(s):  
Julia Tedesco ◽  
Joice Cagliari ◽  
Carolina Danielski Aquino
Keyword(s):  
Ice Age ◽  
Late Paleozoic ◽  
Interglacial Period ◽  
Fine Grained ◽  
Geochemical Proxies ◽  
Late Paleozoic Ice Age ◽  
Paraná Basin ◽  
Parana Basin

ABSTRACT Fine-grained rhythmites are a recurrent sedimentary facies in glacially influenced marine and lacustrine sequences throughout geological time. Paleoenvironmental interpretation of these ancient deposits has been a challenge, because similar rhythmites may have formed in different depositional contexts. In the Paraná Basin, the Itararé Group contains numerous successions of fine-grained rhythmites, deposited in the Carboniferous during the Late Paleozoic Ice Age (LPIA). The described rhythmites are characterized by the intercalation of fine-grained sandstones and siltstones with clay and clayey siltstones. We have identified two distinct types of rhythmites based on the contact between couplets, couplets thickness, sedimentary structures, and geochemical proxies. Type 1 rhythmites are characterized by intercalation of very fine-grained sandstone–siltstone (60–90%) with claystone (40–10%) and normal grading. Type 2 rhythmites are characterized by couplets of siltstone (50%) and claystone (50%), with a sharp contact within couplets. Type 1 rhythmites are interpreted as turbidity-current deposits, and Type 2 as distal deposits of hypopycnal flow. Geochemical proxies suggest deposition of the rhythmites under marine conditions, in a period of rising temperature and humidity, and with intensified chemical weathering. These paleoenvironmental characteristics are in agreement with the interglacial period. The preservation of thick rhythmite successions of the Itararé Group in the southern part of the basin was controlled by the constant creation of accommodation space inside paleovalleys.

A mantle flow mechanism for the late Paleozoic subsidence of the Paraná Basin

2000 ◽  
Vol 105 (B7) ◽  
pp. 16359-16370 ◽  
Author(s):  
Russell N. Pysklywec ◽  
Marcia C. L. Quintas
Keyword(s):  
Late Paleozoic ◽  
Mantle Flow ◽  
Flow Mechanism ◽  
Paraná Basin ◽  
Parana Basin

scholarly journals A review on late Paleozoic ice-related erosional landforms in the Paraná Basin: origin and paleogeographical implications

2016 ◽  
Vol 46 (2) ◽  
pp. 147-166 ◽  
Author(s):  
Eduardo Luiz Menozzo da Rosa ◽  
Fernando Farias Vesely ◽  
Almério Barros França
Keyword(s):  
Ice Age ◽  
Late Paleozoic ◽  
Precambrian Basement ◽  
Review Of The Literature ◽  
Ice Flow ◽  
Late Paleozoic Ice Age ◽  
Paraná Basin ◽  
Flow Directions ◽  
Parana Basin ◽  
Meso Scale

ABSTRACT: The Late Paleozoic Ice Age is recorded in the Paraná Basin as glacial deposits, deformational features and ice-related erosional landforms of the Itararé Group. Erosional landforms are often employed to build paleogeographic models that depict the location of ice masses and paleo ice-flow directions. This paper provides a review of the literature and new data on micro- to meso-scale ice-related, erosional landforms of the Paraná Basin. Examined landforms can be placed into four broad categories based on their mode of origin. Subglacial landforms on rigid substrates occur on the Precambrian basement or on older units in the Paraná Basin. They include streamlined landforms and striated pavements formed by abrasion and/or plucking beneath advancing glaciers. Subglacial landforms on soft beds are intraformational surfaces generated by erosion and deformation of unconsolidated deposits when overridden by glaciers. Ice-keel scour marks are soft-sediment striated/grooved landforms developed by the scouring of free-floating ice masses on underlying sediments. Striated clast pavements are horizons containing aligned clasts that are abraded subglacially due to the advance of glaciers on unconsolidated deposits. Only those erosional landforms formed subglacially can be used as reliable paleo ice-flow indicators. Based on these data, the paleogeography of the Paraná Basin during the Late Paleozoic Ice Age fits into a model of several glacial lobes derived from topographically-controlled ice spreading centers located around the basin instead of a single continental ice sheet.

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