Periglacial evidence for a 1.91–1.89 Ga old glacial period at low latitude, Central Sweden

Kuipers, Gerrit; Beunk, F.F.; Wateren, F.M. van der

doi:10.1111/gto.12027

Cited by 16 publications

(16 citation statements)

References 9 publications

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“…The grooved surface exhibits vertical sandstone-filled cracks up to 5 cm wide and >20 cm deep outlining irregular polygons several metres across, interpreted as frost-fissure casts formed by thermal contraction-cracking in a frigid, windy periglacial setting. Kuipers et al (2013) interpreted a V-shaped, 1.7 m-deep wedge structure developed in 1.9 Ga dacitic metavolcanic sediments in central Sweden to be a periglacial ice-wedge cast.…”

Section: Palaeoproterozoic Australia Europe North Americamentioning

confidence: 98%

Strongly seasonal Proterozoic glacial climate in low palaeolatitudes: Radically different climate system on the pre-Ediacaran Earth

Williams

Schmidt

Young

2016

Geoscience Frontiers

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Proterozoic (pre-Ediacaran) glaciations occurred under strongly seasonal climates near sea level in low palaeolatitudes. Metre-scale primary sand wedges in Cryogenian periglacial deposits are identical to those actively forming, through the infilling of seasonal (winter) thermal contraction-cracks in permafrost by windblown sand, in present-day polar regions with a mean monthly air temperature range of 40°C and mean annual air temperatures of -20°C or lower. Varve-like rhythmites with dropstones in Proterozoic glacial successions are consistent with an active seasonal freeze-thaw cycle. The seasonal (annual) oscillation of sea level recorded by tidal rhythmites in Cryogenian glacial successions indicates a significant seasonal cycle and extensive open seas. Palaeomagnetic data determined directly for Proterozoic glacial deposits and closely associated rocks indicate low palaeolatitudes: Cryogenian deposits in South Australia accumulated at ≤10°, most other Cryogenian deposits at <20° and Palaeoproterozoic deposits at <15° palaeolatitude. Palaeomagnetic data imply that the Proterozoic geomagnetic field approximated a geocentric axial dipole, hence palaeolatitudes represent geographic latitudes. The Cryogenian glacial environment included ice-free, continental permafrost regions with ground frozen on a kyr time-scale, aeolian sandsheets, extensive and long-lived open seas, and an active hydrological cycle. This palaeoenvironment conflicts with the 'snowball Earth' and 'slushball Earth' hypotheses, which cannot accommodate large seasonal changes of temperature near the equator. Consequently, their proponents have attempted to refute the evidence for strong seasonality by M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT 2introducing Popperian 'auxiliary assumptions'. However, non-actualistic arguments that the Cryogenian sand wedges indicate diurnal or weakly seasonal temperature changes are based on misunderstandings of periglacial processes. Modelling of a strongly seasonal climate for a frozen-over Earth is invalidated by the evidence for persistent open seas and ice-free continental regions during Cryogenian glaciations, and gives a mean monthly air temperature range of only ≤10°C for ≤10° latitude. By contrast, a strongly seasonal climate in low palaeolatitudes, based on the actualistic interpretation of cryogenic sand wedges and other structures, is consistent with a high obliquity of the ecliptic (>54°) during Proterozoic lowlatitude glaciations, whereby the equator would be cooler than the poles, on average, and global seasonality would be greatly amplified.

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Section: Palaeoproterozoic Australia Europe North Americamentioning

confidence: 98%

Strongly seasonal Proterozoic glacial climate in low palaeolatitudes: Radically different climate system on the pre-Ediacaran Earth

Williams

Schmidt

Young

2016

Geoscience Frontiers

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“…10°, the bedding dips at 75° to N55E, and the outcrop surface is nearly at a right angle to the stratification (only ~5° oblique). Modified after photographs by Kuipers et al 27 . [Colour figure can be viewed at wileyonlinelibrary.com]…”

Section: Ice‐wedge Pseudomorph and Associated Deformations In The Stumentioning

confidence: 99%

“…ice ages occurred occasionally at different times during the Proterozoic but are conspicuously absent during a long Paleoproterozoic–Mesoproterozoic temperate interval ( c . 2.3 Ga to 750 Ma 26 ), known as the “Proterozoic glacial gap.” 22 However, the recent report of an ice‐wedge pseudomorph and related periglacial structures 27 in a c . 1.9 Ga lithified bedrock of the volcano‐sedimentary Bergslagen Group (BG 28 ) in the Svecofennian orogen of the Fennoscandian Shield in Sweden suggests an as yet little known ice age during that supposed “glacial gap”, prior to the Cryogenian period.…”

Section: Introductionmentioning

confidence: 99%

“…1.9 Ga lithified bedrock of the volcano‐sedimentary Bergslagen Group (BG 28 ) in the Svecofennian orogen of the Fennoscandian Shield in Sweden suggests an as yet little known ice age during that supposed “glacial gap”, prior to the Cryogenian period. After the initial report, 27 further work was carried out to better understand the significance of these periglacial features as to their thermal processes and the permafrost conditions under which they developed and to better constrain their age through radiometric dating. Here, this ancient ice‐wedge pseudomorph and its environmental implications are discussed in detail, in particular evidence derived from this feature for the existence of permafrost.…”

Section: Introductionmentioning

confidence: 99%

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Evidence of permafrost in the Paleoproterozoic (c. 1.9 Ga) of Central Sweden

Vandenberghe

Kuipers²,

Beunk

et al. 2020

Permafrost & Periglacial

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This paper reports on an ice‐wedge pseudomorph that formed and is preserved in metavolcanic host material that was later transformed to metamorphic solid bedrock. It has been dated to 1,895 ± 5 Ma by U–Pb geochronology of zircon in the bedrock, an Early Proterozoic age. Detailed observation of the deformation structures of the wedge points to an ice‐wedge pseudomorph based on typical downbending around the wedge and vertical lamination in the inner part of the wedge due to slumping into the wedge after the ice melted, along with a few remains of lateral pressure structures (such as folds and upturned strata) in the adjacent host sediment. The interpretation of the wedge structure as an ice‐wedge pseudomorph confirms previous work on this topic. This ice‐wedge pseudomorph demonstrates for the first time the existence of permafrost at c. 1.9 Ga. It indicates that permafrost and associated conditions were present in lowlands at low latitude at discrete time intervals early in Earth’s history. Although some caution should be applied, mean annual air temperature appears to have been slightly below the freezing point at that time.

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“…A few notable exceptions have been recognized. Williams (2005) and Kuipers et al (2013) Using Re-Os geochronology, the authors dated a series of organic-rich shales over-and underlying the glacial diamictite unit within the Vazante Group, constraining the age of the glaciation to between 1.3 and 1.1 Ga (Geboy et al, 2013). This age estimate would place the Vazante Group diamictite well within the Mesoproterozoic.…”

Section: A 15 Billion-year Hothouse?mentioning

confidence: 99%

Late Proterozoic Transitions in Climate, Oxygen, and Tectonics, and the Rise of Complex Life

Planavsky

Tarhan

Bellefroid

et al. 2015

Paleontol. Soc. pap.

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The transition to the diverse and complex biosphere of the Ediacaran and early Paleozoic is the culmination of a complex history of tectonic, climate, and geochemical development. Although much of this rise occurred in the middle and late intervals of the Neoproterozoic Era (1000–541 million years ago [Ma]), the foundation for many of these developments was laid much earlier, during the latest Mesoproterozic Stenian Period (1200–1000 Ma) and early Neoproterozoic Tonian Period (1000–720 Ma). Concurrent with the development of complex ecosystems, changes in the composition, configuration, and tectonic interaction between continental plates have been proposed as major shapers of both climate and biogeochemical cycling, but there is little support in the geologic record for overriding tectonic controls. Biogeochemical evidence, however, suggests that an expansion of marine oxygen concentrations may have stabilized nutrient cycles and created more stable environmental conditions under which complex, eukaryotic life could gain a foothold and flourish. The interaction of tectonic, biogeochemical, and climate processes, as described in this paper, resulted in the establishment of habitable environments that fostered the Ediacaran and early Phanerozoic radiations of animal life and the emergence of complex, modern-style ecosystems.

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Periglacial evidence for a 1.91–1.89 Ga old glacial period at low latitude, Central Sweden

Cited by 16 publications

References 9 publications

Strongly seasonal Proterozoic glacial climate in low palaeolatitudes: Radically different climate system on the pre-Ediacaran Earth

Strongly seasonal Proterozoic glacial climate in low palaeolatitudes: Radically different climate system on the pre-Ediacaran Earth

Evidence of permafrost in the Paleoproterozoic (c. 1.9 Ga) of Central Sweden

Late Proterozoic Transitions in Climate, Oxygen, and Tectonics, and the Rise of Complex Life

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