Guadalupian, Middle Permian) Mass Extinction in NW Pangea (Borup Fiord, Arctic Canada): a Global Crisis Driven by Volcanism and Anoxia
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The Capitanian (Guadalupian, Middle Permian) mass extinction in NW Pangea (Borup Fiord, Arctic Canada): A global crisis driven by volcanism and anoxia David P.G. Bond1†, Paul B. Wignall2, and Stephen E. Grasby3,4 1Department of Geography, Geology and Environment, University of Hull, Hull, HU6 7RX, UK 2School of Earth and Environment, University of Leeds, Leeds, LS2 9JT, UK 3Geological Survey of Canada, 3303 33rd Street N.W., Calgary, Alberta, T2L 2A7, Canada 4Department of Geoscience, University of Calgary, 2500 University Drive N.W., Calgary Alberta, T2N 1N4, Canada ABSTRACT ing gun of eruptions in the distant Emeishan 2009; Wignall et al., 2009a, 2009b; Bond et al., large igneous province, which drove high- 2010a, 2010b), making this a mid-Capitanian Until recently, the biotic crisis that oc- latitude anoxia via global warming. Although crisis of short duration, fulfilling the second cri- curred within the Capitanian Stage (Middle the global Capitanian extinction might have terion. Several other marine groups were badly Permian, ca. 262 Ma) was known only from had different regional mechanisms, like the affected in equatorial eastern Tethys Ocean, in- equatorial (Tethyan) latitudes, and its global more famous extinction at the end of the cluding corals, bryozoans, and giant alatocon- extent was poorly resolved. The discovery of Permian, each had its roots in large igneous chid bivalves (e.g., Wang and Sugiyama, 2000; a Boreal Capitanian crisis in Spitsbergen, province volcanism. Weidlich, 2002; Bond et al., 2010a; Chen et al., with losses of similar magnitude to those in 2018). In contrast, pelagic elements of the fauna low latitudes, indicated that the event was INTRODUCTION (ammonoids and conodonts) suffered a later, geographically widespread, but further non- ecologically distinct, extinction crisis in the ear- Tethyan records are needed to confirm this as The Capitanian (Guadalupian Series, Middle liest Lopingian (Huang et al., 2019). Although a a true mass extinction. The cause of this crisis Permian) crisis is among the least understood severe extinction of Capitanian brachiopods has is similarly controversial: While the temporal of the major mass extinctions. It has been in- been found in the Boreal sections of Spitsbergen coincidence of the extinction and the onset terpreted as extinction comparable to the “Big (Bond et al., 2015), evaluation of the true geo- of volcanism in the Emeishan large igneous 5” Phanerozoic crises (Stanley and Yang, 1994; graphic extent of the crisis requires more evi- province in China provides a clear link be- Bond et al., 2010a, 2015; Stanley, 2016) or, al- dence from outside Tethys to resolve the third tween those phenomena, the proximal kill ternatively, as a gradually attained low point in criterion. mechanism is unclear. Here, we present an Permian diversity of regional extent and there- The losses in China coincided with the onset integrated fossil, pyrite framboid, and geo- fore not a mass extinction at all (Yang et al., of Emeishan large igneous province volcanism chemical study of the Middle to Late Perm- 2000; Clapham et al., 2009; Payne and Clapham, in the southwest of the country (Wignall et al., ian section of the Sverdrup Basin at Borup 2012; Groves and Wang, 2013). Although there 2009a; Huang et al., 2019), suggesting a role for Fiord, Ellesmere Island, Arctic Canada. As is no universally accepted definition of “mass large igneous province activity. The recent de- in Spitsbergen, the Capitanian extinction extinction,” key criteria include the following: A velopment of mercury as a proxy for volcanism is recorded by brachiopods in a chert/lime- mass extinction should have significant impact (Sanei et al., 2012) permits further evaluation of stone succession 30–40 m below the Permian- on a range of biota, it should be of geologically the large igneous province–extinction link in lo- Triassic boundary. The extinction level shows short duration, and it should be of global extent. cations far removed from the site of volcanism. elevated concentrations of redox-sensitive Until recently, most studies have focused on Several large igneous province–driven kill trace metals (Mo, V, U, Mn), and contempo- equatorial (Tethyan) records, especially those mechanisms have been implicated in the Capi- rary pyrite framboid populations are domi- from South China, where fusulinacean foramini- tanian crisis, especially marine anoxia, which is nated by small individuals, suggestive of a fers and brachiopods lost 82% and 87% of spe- implicated in numerous other mass extinction causal role for anoxia in the wider Boreal cies, respectively (Jin et al., 1994; Shen and Shi, scenarios (see reviews in Wignall, 2001; Bond crisis. Mercury concentrations—a proxy for 1996; Bond et al., 2010a), thus fulfilling the first and Wignall, 2014; Bond and Grasby, 2017). volcanism—are generally low throughout criterion. These losses were originally ascribed Notably, the Capitanian losses in Spitsbergen the succession but are elevated at the extinc- to the Guadalupian-Lopingian Series boundary coincided with a phase of benthic oxygen deple- tion level, and this spike withstands normal- (end of Capitanian Stage), hence the widespread tion (Bond et al., 2015). Other purported Capi- ization to total organic carbon, total sulfur, use of the term “end-Guadalupian extinction” tanian extinction mechanisms include cooling and aluminum. We suggest this is the smok- in earlier literature. However, the South China (Isozaki et al., 2007), death-by-photosynthetic benthic crisis has now been accurately dated to shutdown at the onset of volcanism (Bond et al., the Jinogondolella altudaensis–Jinogondolella 2010a, 2010b), ocean acidification caused by † [email protected]. prexuanhanensis conodont zones (Shen and Shi, volcanogenic CO2 (McGhee et al., 2013), and GSA Bulletin; May/June 2020; v. 132; no. 5/6; p. 931–942; https://doi.org/10.1130/B35281.1; 8 figures; 3 tables; published online 30 August 2019. © 2019 The Authors. Gold Open Access: 931 This paper is published under the terms of the CC-BY license. Downloaded from http://pubs.geoscienceworld.org/gsa/gsabulletin/article-pdf/132/5-6/931/4990324/931.pdf by guest on 28 September 2021 Bond et al. volcanogenic toxic metal poisoning (Grasby presence of Crockerland, a structural high that environmental and biotic changes on the NW et al., 2015). formed the northern basin rim (Embry, 1988, margin of Pangea. Thus, controversy surrounds whether the 1989). The Middle to Late Permian succession Capitanian crisis was a true global extinction and at Borup Fiord (81°00′33.4″N, 81°30′51.0″W; MATERIAL AND METHODS whether (and how) the Emeishan large igneous Fig. 2) formed at around 40°N on a shallow, province was responsible. We address this with open-marine siliceous ramp near the basin’s Facies and Fossils a new record from the Sverdrup Basin (Arctic northeastern margin and belongs to the De- Canada). Our study presents brachiopod range gerböls and Lindström Formations (but shares Sedimentary logging was undertaken through data from the Degerböls and Lindström Forma- lithological similarities with their more distal ∼100 m of the Degerböls and Lindström Forma- tions of Ellesmere Island, Permian-aged mixed equivalents, the van Hauen and Black Stripe tions and the basal meters of the Blind Fiord For- spiculitic chert/carbonate units that formed on Formations, respectively; Beauchamp et al., mation at Borup Fiord, which was accessed by a cool, siliciclastic ramp in the Boreal Ocean 2009; Embry and Beauchamp, 2019). The suc- helicopter in July 2015. The outcrop lies along- (Embry, 1988; Embry and Beauchamp, 2008, cession is composed of white to pale-gray spic- side an east-west–trending glacier and provides 2019; Beauchamp et al., 2009). We assessed the ulitic cherts and numerous limestone interbeds a continuous exposure of fresh surfaces polished role of redox changes during this interval using (Beauchamp and Grasby, 2012). The Lindström by ice movement. Facies, and trace and body a combination of petrographic and geochemical Formation is overlain conformably by the latest fossils (principally brachiopods) were identified approaches, and we further examined the link Permian–Early Triassic Blind Fiord Formation in the field. The field observations were supple- between these factors and the Emeishan large (Grasby and Beauchamp, 2008; Proemse et al., mented with analysis of 24 thin sections. igneous province using the mercury proxy for 2013) at Borup Fiord, while an unconformity volcanism. The precise ages of the Degerböls marks this contact in more proximal settings. As Redox Proxies and Lindström Formations are unclear, and we in other regions, notably the lithostratigraphi- investigated this through lithostratigraphic and cally similar Svalbard and Barents Sea, the The concentrations of redox-sensitive trace chemostratigraphic comparison with better- Permian-Triassic boundary lies a few meters metals in marine sediment provide a measure of dated Boreal successions in East Greenland and above the major lithological change at the for- ancient depositional conditions, because the re- Spitsbergen. mational contact (Beauchamp et al., 2009). The duced forms of many metals (e.g., Mo, U, V, and Blind Fiord Formation is a thick succession of Mn) are insoluble in seawater; therefore, these REGIONAL GEOLOGY offshore mudstones, siltstones, and shelf-slope elements are scavenged by sediment under anox- sandstones that record major flooding, as well as ic conditions. The U, Th, and K concentrations The