Chapter 1 The geological record of Neoproterozoic ice ages

Arnaud, Emmanuelle; Halverson, Galen P.; Shields, Graham A.

doi:10.1144/m36.1

Cited by 46 publications

(31 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Burtman (2006) also recognized two major episodes of volcanic activity along the southern and western boundary of KNNTS in the Early Devonian and in the mid-Carboniferous to Permian, while no active margin development is known there from the Cambrian and Ordovician. Precambrian (Late Ediacaran, not Cryogenian) diamictites of the Baikanur Formation are sedimentological markers in Karatau-Naryn (Chumakov 2011), but are unknown from other tectonostratigraphic units in the Kazakh Orogen (Arnaud et al 2011). …”

Section: Karatau-naryn Microcontinent and North Tien Shanmentioning

confidence: 99%

Late Ordovician palaeogeography and the positions of the Kazakh terranes through analysis of their brachiopod faunas

Popov

Cocks

2017

Acta Geologica Polonica

View full text Add to dashboard Cite

ABSTRACT:Popov, L.E. and Cocks, L.R.M. 2017. Late Ordovician palaeogeography and the positions of the Kazakh terranes through analysis of their brachiopod faunas. Acta Geologica Polonica, 67 (3), 323-380. Warszawa.Detailed biogeographical and biofacies analyses of the Late Ordovician brachiopod faunas with 160 genera, grouped into 94 faunas from individual lithotectonic units within the Kazakh Orogen strongly support an archipelago model for that time in that area. The Kazakh island arcs and microcontinents within several separate clusters were located in the tropics on both sides of the Equator. Key units, from which the Late Ordovician faunas are now well known, include the Boshchekul, Chingiz-Tarbagatai, and Chu-Ili terranes. The development of brachiopod biogeography within the nearly ten million year time span of the Late Ordovician from about 458 to 443 Ma (Sandbian, Katian, and Hirnantian), is supported by much new data, including our revised identifications from the Kazakh Orogen and elsewhere. The Kazakh archipelago was west of the Australasian segment of the Gondwana Supercontinent, and relatively near the Tarim, South China and North China continents, apart from the Atashu-Zhamshi Microcontinent, which probably occupied a relatively isolated position on the south-western margin of the archipelago. Distinct faunal signatures indicate that the Kazakh terranes were far away from Baltica and Siberia throughout the Ordovician. Although some earlier terranes had joined each other before the Middle Ordovician, the amalgamation of Kazakh terranes into the single continent of Kazakhstania by the end of the Ordovician is very unlikely. The Late Ordovician brachiopods from the other continents are also compared with the Kazakh faunas and global provincialisation statistically determined.

show abstract

Section: Karatau-naryn Microcontinent and North Tien Shanmentioning

confidence: 99%

Late Ordovician palaeogeography and the positions of the Kazakh terranes through analysis of their brachiopod faunas

Popov

Cocks

2017

Acta Geologica Polonica

View full text Add to dashboard Cite

show abstract

“…It is well understood that the identification of proglacial deposits is crucial when searching for a related ice-margin upstream -such domains are abundantly illustrated in glacial facies models (Boulton, 1972;Edwards, 1989;Einsele, 1992;Lønne et al, 2001;Le Heron et al, 2009) -yet there are few studies about well-documented and precisely positioned Proterozoic (e.g., Arnaud et al, 2011;Domack and Hoffman, 2011) and Palaeozoic (e.g., Visser, 1997) to Cenozoic icefront zones. Sedimentary evidence of ice margins resulting from more or less stationary ice fronts constitutes indeed spatially subordinate features in comparison with extensive till covers and other proglacial deposits such as glaciomarine to glaciolacustrine deposits.…”

Section: Ice-marginal Wedges and The Recognition Of Palaeo-ice Frontsmentioning

confidence: 99%

Sedimentary imprints of former ice-sheet margins: Insights from an end-Ordovician archive (SW Libya)

Girard

Ghienne

Du-Bernard

et al. 2015

Earth-Science Reviews

View full text Add to dashboard Cite

“…There are no known glacial rocks below the Smalfjord Formation; evidence of an earlier Cryogenian ("Sturtian") glacial event is, therefore, absent, unlike many other Neoproterozoic successions (cf. Arnaud et al, 2011). Whether this is because the Sturtian glaciation, for which there is a wide range of isotopic ages (741-643 Ma; cf.…”

Section: Stop 81: Sjåbuselva East Of Kibymentioning

confidence: 99%

Neoproterozoic Glacial and Associated Facies in the Tanafjord-Varangerfjord Area, Finnmark, North Norway

Rice¹,

Edwards²,

Hansen³

2012

Neoproterozoic Glacial and Associated Facies in the Tanafjord-Varangerfjord Area, Finnmark, North Norway

View full text Add to dashboard Cite

This excursion guide describes the glacigenic rocks of the Smalfjord and Mortensnes Formations, and parts of the intervening Nyborg Formation, at the base of the Vestertana Group in the Tanafjord-Varangerfjord region of East Finnmark, NorthNorway. These are agreed to be either of glacial (sensu lato) origin or signifi cant to our understanding of Neoproterozoic glacial processes and events. The Smalfjord and Mortensnes Formations have been equated with the Marinoan (636.3 ± 4.9 Ma and 635.5 ± 1.2 Ma) and Gaskiers (584-582 Ma) glaciations, respectively. The rocks, which are superbly exposed, display a wide range of sedimentary lithologies/facies; lodgment, banded, deformation, fl ow, and melt-out diamictites; as well as glaciomarine, proglacial, and fl uvioglacial sediments. Diamictites derived from carbonate units showing the Trezona and Wonoka negative δ 13 C anomalies are seen.Glaciotectonic and/or soft-sediment structures described include folds, normal and thrust faults (imbricate fans), fl anking structures, shear-sense criteria (sigma clasts), striations (with paleoloess), lobate-cuspate contacts, downward intrusion of fl uidized sediments (with bridge structures), pro-and subglacial channels, nested channels, graded beds, possible iceberg dump structures, ghost clasts, dropstones and lonestones, allochthonous rafts of substrate sediments, ball-and-pillow structures, convolute laminations (pseudonodules), delta foresets, ice-crystal molds, sandstone dikes, and a possible kettle hole. The complex geometry of the sub-Smalfjord unconformity onto older Neoproterozoic sediments and the Archean Baltic Shield is documented at several scales. Marinoan cap dolostones (Maieberg negative δ 13 C anomaly), with typical sheet cracking (and "pseudostromatolites") and atypical clastic interbeds, are described from the base of the Nyborg Formation at several localities.

show abstract

Chapter 1 The geological record of Neoproterozoic ice ages

Cited by 46 publications

References 32 publications

Late Ordovician palaeogeography and the positions of the Kazakh terranes through analysis of their brachiopod faunas

Late Ordovician palaeogeography and the positions of the Kazakh terranes through analysis of their brachiopod faunas

Sedimentary imprints of former ice-sheet margins: Insights from an end-Ordovician archive (SW Libya)

Neoproterozoic Glacial and Associated Facies in the Tanafjord-Varangerfjord Area, Finnmark, North Norway

Contact Info

Product

Resources

About