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

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.

Download Full-text

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

Brazilian Journal of Geology ◽

10.1590/2317-4889201620160050 ◽

2016 ◽

Vol 46 (2) ◽

pp. 147-166 ◽

Cited By ~ 15

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.

Download Full-text

Lontras Shale (Paraná Basin, Brazil): Insightful analysis and commentaries on paleoenvironment and fossil preservation into a deglaciation pulse of the Late Paleozoic Ice Age

Palaeogeography Palaeoclimatology Palaeoecology ◽

10.1016/j.palaeo.2020.109850 ◽

2020 ◽

Vol 555 ◽

pp. 109850 ◽

Cited By ~ 1

Author(s):

Lucas D. Mouro ◽

Mírian Liza Alves Forancelli Pacheco ◽

João H.Z. Ricetti ◽

Ana K. Scomazzon ◽

Rodrigo S. Horodyski ◽

...

Keyword(s):

Ice Age ◽

Late Paleozoic ◽

Late Paleozoic Ice Age ◽

Paraná Basin ◽

Insightful Analysis ◽

Fossil Preservation ◽

Parana Basin

Download Full-text

High-latitude ice and climate control on sediment supply across SW Gondwana during the late Carboniferous and early Permian

Geological Society of America Bulletin ◽

10.1130/b35852.1 ◽

2021 ◽

Author(s):

N. Griffis ◽

I. Montañez ◽

R. Mundil ◽

D. Le Heron ◽

P. Dietrich ◽

...

Keyword(s):

Detrital Zircon ◽

Sediment Supply ◽

Ice Age ◽

Late Paleozoic ◽

Far Field ◽

Early Permian ◽

Late Paleozoic Ice Age ◽

Paraná Basin ◽

Sw Gondwana ◽

Parana Basin

The response of sediment routing to climatic changes across icehouse-to-greenhouse turnovers is not well documented in Earth’s pre-Cenozoic sedimentary record. Southwest Gondwana hosts one of the thickest and most laterally extensive records of Earth’s penultimate icehouse, the late Paleozoic ice age. We present the first high-resolution U-Pb zircon chemical abrasion−isotope dilution−thermal ionization mass spectrometry (CA-ID-TIMS) analysis of late Paleozoic ice age deposits in the Kalahari Basin of southern Africa, which, coupled with existing CA-ID-TIMS zircon records from the Paraná and Karoo Basins, we used to refine the late Paleozoic ice age glacial history of SW Gondwana. Key findings from this work suggest that subglacial evidence in the Kalahari region is restricted to the Carboniferous (older than 300 Ma), with glacially influenced deposits culminating in this region by the earliest Permian (296 Ma). The U-Pb detrital zircon geochronologic records from the Paraná Basin of South America, which was located downstream of the Kalahari Basin in the latest Carboniferous and Permian, indicate that large-scale changes in sediment supplied to the Paraná were contemporaneous with shifts in the SW Gondwana ice record. Gondwanan deglaciation events were associated with the delivery of far-field, African-sourced sediments into the Paraná Basin. In contrast, Gondwanan glacial periods were associated with the restriction of African-sourced sediments into the basin. We interpret the influx of far-field sediments into the Paraná Basin as an expansion of the catchment area for the Paraná Basin during the deglaciation events, which occurred in the latest Carboniferous (300−299 Ma), early Permian (296 Ma), and late early Permian (<284 Ma). The coupled ice and detrital zircon records for this region of Gondwana present opportunities to investigate climate feedbacks associated with changes in freshwater and nutrient delivery to late Paleozoic ocean basins across the turnover from icehouse to greenhouse conditions.

Download Full-text

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

Geology ◽

10.1130/g46740.1 ◽

2019 ◽

Vol 47 (12) ◽

pp. 1146-1150 ◽

Cited By ~ 18

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.

Download Full-text