Environmental changes in the Late Ordovician-early Silurian: Review and new insights from black shales and nitrogen isotopes

Melchin, Michael J.; Mitchell, Charles E.; Holmden, Chris; Štorch, Petr

doi:10.1130/b30812.1

Cited by 252 publications

(278 citation statements)

References 235 publications

(6 reference statements)

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“…triggered by abiotic, environmental perturbations of the graptolite ecosystem related to rapid changes in the marine climate (13,28,29). The link between Ordovician−Silurian evolutionary dynamics of the marine fauna and global climatic events is well supported (30)(31)(32)(33)(34)(35)(36), especially for the LOME and the Sheinwoodian climatic− evolutionary events and their accompanying perturbations in the carbon cycle.…”

Section: Resultsmentioning

confidence: 87%

Greenhouse−icehouse transition in the Late Ordovician marks a step change in extinction regime in the marine plankton

Crampton

Cooper

Sadler

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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Two distinct regimes of extinction dynamic are present in the major marine zooplankton group, the graptolites, during the Ordovician and Silurian periods (486−418 Ma). In conditions of "background" extinction, which dominated in the Ordovician, taxonomic evolutionary rates were relatively low and the probability of extinction was highest among newly evolved species ("background extinction mode"). A sharp change in extinction regime in the Late Ordovician marked the onset of repeated severe spikes in the extinction rate curve; evolutionary turnover increased greatly in the Silurian, and the extinction mode changed to include extinction that was independent of species age ("high-extinction mode"). This change coincides with a change in global climate, from greenhouse to icehouse conditions. During the most extreme episode of extinction, the Late Ordovician Mass Extinction, old species were selectively removed ("mass extinction mode"). Our analysis indicates that selective regimes in the Paleozoic ocean plankton switched rapidly (generally in <0.5 My) from one mode to another in response to environmental change, even when restoration of the full ecosystem was much slower (several million years). The patterns observed are not a simple consequence of geographic range effects or of taxonomic changes from Ordovician to Silurian. Our results suggest that the dominant primary controls on extinction throughout the lifespan of this clade were abiotic (environmental), probably mediated by the microphytoplankton.T he importance of the marine plankton in both the carbon cycle and in the food web that supports the diversity of marine life is undisputed. However, the evolutionary dynamics of planktic species and the factors controlling their diversity and evolutionary turnover are still poorly known (1, 2). This is particularly so for the Paleozoic, where problems of preservation and sampling bias, and poor time resolution, have precluded detailed analysis. How does the marine plankton respond to environmental perturbations arising from climate change over geological time? How does background extinction differ from episodic and mass extinction in the pelagic realm? Is the risk of plankton species extinction dependent on the amount of time since the species originated (3)? These questions have important implications for macroevolutionary process, stability of marine ecosystems, and modern biodiversity conservation (3-5). Here, using a new global data set of unparalleled temporal resolution, we attempt to answer these questions.The graptoloid clade (order Graptoloidea) constituted the main component of the early Paleozoic macrozooplankton from the beginning of the Ordovician to the Early Devonian (6). Graptoloids were colonial filter-feeding protochordates, generally ranging from a few millimeteres up to ∼200 mm in maximum dimension, which lived suspended in the water column in a range of depth zones. They have been used extensively for correlation and zonation (7-10), and the stratigraphic distributions of species are well docum...

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Section: Resultsmentioning

confidence: 87%

Greenhouse−icehouse transition in the Late Ordovician marks a step change in extinction regime in the marine plankton

Crampton

Cooper

Sadler

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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“…Several lines of evidence, including biomarkers [37], nitrogen isotopes [38,39], molybdenum isotopes [14,40], iron speciation [14] and black shale distributions [39], suggest that the onset of the Hirnantian icehouse climate state was accompanied by increased oxygenation of shelf environments. Many of the species found in deeper-water environments during the late Katian were small and thin-shelled [41], like modern low-oxygen specialists [42].…”

Section: Resultsmentioning

confidence: 99%

Biogeographic and bathymetric determinants of brachiopod extinction and survival during the Late Ordovician mass extinction

2016

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The Late Ordovician mass extinction (LOME) coincided with dramatic climate changes, but there are numerous ways in which these changes could have driven marine extinctions. We use a palaeobiogeographic database of rhynchonelliform brachiopods to examine the selectivity of Late Ordovician -Early Silurian genus extinctions and evaluate which extinction drivers are best supported by the data. The first (latest Katian) pulse of the LOME preferentially affected genera restricted to deeper waters or to relatively narrow (less than 358) palaeolatitudinal ranges. This pattern is only observed in the latest Katian, suggesting that it reflects drivers unique to this interval. Extinction of exclusively deeper-water genera implies that changes in water mass properties such as dissolved oxygen content played an important role. Extinction of genera with narrow latitudinal ranges suggests that interactions between shifting climate zones and palaeobiogeography may also have been important. We test the latter hypothesis by estimating whether each genus would have been able to track habitats within its thermal tolerance range during the greenhouse -icehouse climate transition. Models including these estimates are favoured over alternative models. We argue that the LOME, long regarded as non-selective, is highly selective along biogeographic and bathymetric axes that are not closely correlated with taxonomic identity.

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“…The Early Ordovician to Early Silurian time interval represents a period of black shale deposition under stratified and anoxic bottom water conditions in many areas of North Africa, the Middle East and Europe, Fig. 1 (Berry, 2010;Leggett, 1980;Thickpenny and Leggett, 1987;Trela and Podhalanska, 2010;Wilde, 1987) including Poland (Melchin et al, 2013;Page et al, 2007). During the Ordovician-Silurian transition, there were considerable changes in the atmosphere, ocean, biosphere and, hence, in the general marine depositional conditions (Underwood et al, 1997) inextricably linked with the Late Ordovician (End Hirnantian) glacial event (Melchin et al, 2013;Sheehan, 2001).…”

Section: Introductionmentioning

confidence: 99%

“…1 (Berry, 2010;Leggett, 1980;Thickpenny and Leggett, 1987;Trela and Podhalanska, 2010;Wilde, 1987) including Poland (Melchin et al, 2013;Page et al, 2007). During the Ordovician-Silurian transition, there were considerable changes in the atmosphere, ocean, biosphere and, hence, in the general marine depositional conditions (Underwood et al, 1997) inextricably linked with the Late Ordovician (End Hirnantian) glacial event (Melchin et al, 2013;Sheehan, 2001). Glaciation events Mustafa, K.A., Sephton M.A., Spathopoulos, F., Watson, J.S., Krzywiec, P. Organic geochemical characteristics of black shales across the Ordovician-Silurian boundary in the Holy Cross Mountains, Central Poland, Marine andPetroleum Geology, doi:10.1016/j.marpetgeo.2015.08.018. 3 have major influence on the productivity and preservation of organic matter due to the changes in oceanic ventilation and circulation that cause oxygenation of the seawater (Berry and Wilde, 1978;Berry, 2010;Wilde, 1987).…”

Section: Introductionmentioning

confidence: 99%

“…9 A&B) in the HCM are consistent with those for the wider Ordovician-Silurian paleoenvironments. For instance, a drastic change in the Mustafa, K.A., Sephton M.A., Spathopoulos, F., Watson, J.S., Krzywiec, P Mountains, Central Poland, Marine andPetroleum Geology, doi:10.1016/j.marpetgeo.2015.08.018. 15 depositional environment, bottom water condition, fossil fauna, and organic matter production and preservation was observed during the transition from the Late Ordovician to the Early Silurian, not only in Poland (Kremer, 2001;Masiak et al, 2003;Podhalanska, 2003;Sawlowicz and Porebska, 1998;Trela et al, 2001), but also in other parts of the world (Armstrong et al, 2009;Lüning et al, 2006;Melchin et al, 2013;Vecoli, 2008).…”

Section: Organic Geochemical Characteristics Of Black Shales Acrossmentioning

confidence: 99%

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Organic geochemical characteristics of black shales across the Ordovician–Silurian boundary in the Holy Cross Mountains, central Poland

Mustafa

Sephton

Watson

et al. 2015

Marine and Petroleum Geology

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Black shales in the Holy Cross Mountains area of Poland provide a record of environmental change across the Ordovician-Silurian boundary. The changing depositional conditions have generated a variation in organic matter contents above and below the boundary. Investigating the organic constitution of these black shales has the potential to reveal how their organic matter contents were generated and how suitable these rocks and their lateral equivalents may be for exploitation as shale and Silurian rocks, these rocks were buried and subjected to thermal maturation. Rock Eval and Mustafa, K.A., Sephton M.A., Spathopoulos, F., Watson, J.S., Krzywiec, P. Organic geochemical characteristics of black shales across the Ordovician-Silurian boundary in the Holy Cross Mountains, Central Poland, Marine and Petroleum Geology, doi:10.1016/j.marpetgeo.2015.08.018. 2 biomarker thermal maturity parameters all indicate that the organic matter is mature and lies within the oil window. The Ordovician and Silurian shales have direct relevance to recent attempts to discover and exploit shale gas reservoirs in Poland. Our data and interpretations suggest that the relatively low TOC values (<2%) and low maturities for gas generation render these rocks unsuitable for commercial shale gas production. The progressive improvement in conditions for preserving organic matter across the Ordovician-Silurian boundary does, however, leave the possibility that more suitable deposits occur in Early Silurian rocks in other parts of the basin.

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Environmental changes in the Late Ordovician-early Silurian: Review and new insights from black shales and nitrogen isotopes

Cited by 252 publications

References 235 publications

Greenhouse−icehouse transition in the Late Ordovician marks a step change in extinction regime in the marine plankton

Greenhouse−icehouse transition in the Late Ordovician marks a step change in extinction regime in the marine plankton

Biogeographic and bathymetric determinants of brachiopod extinction and survival during the Late Ordovician mass extinction

Organic geochemical characteristics of black shales across the Ordovician–Silurian boundary in the Holy Cross Mountains, central Poland

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