The Central Iapetus magmatic province: An updated review and link with the ca. 580 Ma Gaskiers glaciation

Abstract

Large igneous provinces and associated silicic magmatism can have a significant global climatic effect, so we explored the relationship between the large igneous province record and the ca. 580 Ma Gaskiers glaciation. The late Ediacaran glaciation exists on at least 14 different paleocontinental blocks, and assuming synchroneity, this Gaskiers glaciation was likely of short duration, with estimates ranging from 1.6 m.y. to 340 k.y. The Central Iapetus magmatic province event found in Laurentia, Baltica, and West Africa consists of multiple pulses in the range 620–520 Ma, with the ca. 580 Ma pulse particularly well developed in North Africa. Based on the age matches of 580–570 Ma Central Iapetus magmatic province pulses and the Gaskiers glaciation, and taking into consideration that there is no robust evidence for a major meteorite impact at the time of the Gaskiers onset, we propose that: (1) the initial silicic ca. 580 Ma pulse of the Ouarzazate event (Anti-Atlas of Morocco) helped to trigger the Gaskiers glaciation, and (2) global warming associated with the subsequent ca. 579–570 Ma continental flood basalts, marking the second stage of the Ouarzazate event, helped to end the ice age.

Large Igneous Province Record Through Time and Implications for Secular Environmental Changes and Geological Time‐Scale Boundaries

“…Owing to their large volume and short duration of emplacement, LIPs and associated SLIPs can have a dramatic effect on global environments. Postulated effects operate over short (up to several years) to long (up to several 100 kyrs and even myrs) timescales and include warming, cooling, acid rain, ocean acidification, ozone depletion increasing UV-B radiation, marine anoxia, mercury poisoning, and sea level changes, many of which are evidenced by, for example, stable isotopic excursions and changes in chemical composition of sediments (Ernst & Youbi, 2017;Bekker & Ernst 2017;Zhang et al, 2018;Grasby et al, 2019;Jones et al, 2019;Svensen et al, 2019;Youbi et al, 2020;Babila & Foster, chapter 17 Youbi et al,Chapter 8 this volume). With increasing precision of U-Pb dating of LIPs, resulting in age uncertainties in some cases less than 50,000 years, an increasing number of Phanerozoic Global Time Scale (GTS) boundaries that were originally defined based on biotic crises (including mass extinctions) can be correlated with LIP events (e.g., Wignall, 2001;Bond & Grasby, 2017;Kasbohm et al, Chapter 2 this volume;Ernst et al, 2020a).…”

“…The ca. 580 Ma pulse of the Central Iapetus Magmatic Province (CIMP, 615-560 Ma) has been tentatively correlated with the 580 Ma Gaskiers glaciation (Pu et al, 2016;Youbi et al, 2020;Youbi et al, Chapter 8 this volume), and this LIP has a potential role in both the initiation and termination of this glaciation.…”

Revised stratigraphic framework for the lower Anti-Atlas Supergroup based on U–Pb geochronology of magmatic and detrital zircons (Zenaga and Bou Azzer-El Graara inliers, Anti-Atlas Belt, Morocco)

“…Abati et al, 2010;Gärtner et al, 2013;2018). However, recent studies in the northern WAC (El Bahat et al, 2013;Söderlund et al, 2013;Youbi et al, 2013;Ikenne et al, 2017) Walsh et al, 2002;Gasquet et al, 2004;El Bahat et al, 2013;Kouyaté et al, 2013;Söderlund et al, 2013;Youbi et al, 2013;El Bahat et al, 2017;Ikenne et al, 2017;Bouougri et al, 2020 ;Youbi et al, 2020). Re-Os geochronology of the sedimentary succession of the Atar Group in the Taoudeni Basin of Mauritania indicated depositional ages ranging from 1109 ± 22 to 1105 ± 37 Ma (Rooney et al, 2010).…”

“…(ii) The Neoproterozoic Pan-African Orogeny . The Neoproterozoic sequences of the Anti-Atlas Belt are composed of units that were involved in the Pan-African Orogeny and the unconformably overlying post-collisional volcano-sedimentary rocks of the Ouarzazate Supergroup, which are a part of the Central Iapetus Magmatic Province (CIMP; Doblas et al, 2002;Maloof et al, 2005;Gasquet et al, 2005Gasquet et al, , 2008Ernst and Youbi, 2017;Tuduri et al, 2018;Youbi et al, 2020). The Neoproterozoic rocks underlying the Ouarzazate Supergroup are subdivided into the lower units (Lkest-Taghdout, Bou-Azzer, and Iriri groups), affected by all Pan-African orogenic events, and the upper units (Saghro and Bou Salda groups), only affected by the latest stage of the Pan-African Orogeny (e.g.…”

“…The later post-collisional, extensional stage (605-542 Ma) is characterized by molasse deposition and magmatism of the Ouarzazate Supergroup, which was followed by the foreland development in the Saharan cratonic basin to the south (Taroudant and Tata groups; e.g. Doblas et al, 2002;Maloof et al, 2005;Gasquet et al, 2005Gasquet et al, , 2008Hefferan et al, 2014;Karaoui et al, 2014;2015;Tuduri et al, 2018;Geyer and Landing, 2006;Youbi et al, 2020).…”