A sulfidic driver for the end-Ordovician mass extinction

Hammarlund, Emma U.; Dahl, Tais W.; Harper, David A. T.; Bond, David P.G.; Nielsen, Arne Thorshøj; Bjerrum, Christian J.; Schovsbo, Niels H.; Schönlaub, Hans Peter; Zalasiewicz, Jan; Canfield, Donald E.

doi:10.1016/j.epsl.2012.02.024

Cited by 188 publications

(127 citation statements)

References 99 publications

Supporting

Mentioning

112

Contrasting

Order By: Relevance

“…Genera that ranged into shallower waters (BA 1 -2) experienced much lower extinction rates than those restricted to deeper waters (BA 3-6). The pattern is not limited to a single region but is apparent across a broad palaeolatitudinal range (figure 2), implying that it reflects the operation of a globalscale environmental driver and that the previously noted demise of the widespread deep water (BA 5-6) Foliomena fauna [14,22] is only the most extreme manifestation of a broader selective sweep. Interpretation of this pattern is complicated by uncertainty regarding the actual depth ranges represented by BAs (which are restricted to shelf and slope settings) [26], but the sign of the depth signal is informative.…”

Section: Resultsmentioning

confidence: 94%

“…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%

“…Previous studies of the LOME have implicated two major drivers of extinction: (i) loss of species inhabiting shallow cratonic seaways that drained as Gondwanan glaciers grew; and (ii) loss of species with narrow and/or relatively warm thermal tolerance ranges as the polar front advanced and the latitudinal temperature gradient steepened [12,13]. Late Ordovician -Early Silurian climatic events seem also to have been associated with major changes in oceanographic circulation, productivity and oxygenation of outer shelf and slope settings [6,14]. Changes in oxygenation, in particular, have been suggested as a major additional agent of extinction, particularly for taxa with planktonic life stages [15 -17].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

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

2016

View full text Add to dashboard Cite

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.

show abstract

Section: Resultsmentioning

confidence: 94%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

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

2016

View full text Add to dashboard Cite

show abstract

“…The Pr/Ph ratio and the homohopane index in the Table 2 (Didyk et al, 1978;Peters et al, 2005;Powell, 1988) suggest that the depositional environment of the organic matter was mostly suboxic, intermittently, and became anoxic for periods as a result of reintroduction of deep anoxic waters to shelf areas during Late Hirnantian sea level rise (Hammarlund et al, 2012). The interpretation of the depositional setting as generally oxic/suboxic is supported by the predominance of C 31 homohopane homologue and the low content of the C 35 homohopane (Peters and Moldowan, 1991).…”

Section: Paleodepositional Environmentsmentioning

confidence: 99%

“…Enhanced preservation is consistent with TOC increase, biomarker ratios, and lithology change across the boundary (Fig 8 and Table 2). The proposal that depositional conditions changed from relatively oxic to relatively reducing across the Ordovician-Silurian boundary owing to a sea level rise (Berry, 2010;Hammarlund et al, 2012;Trela, 2007;Zhang et al, 2011), during which black graptolitic and organic rich shales were deposited, can be tested using biomarker data and the Pr/Ph ratio and homohopane index ( Fig. 8 and Table 2) that represent clear evidence of such changes (Fig.…”

Section: Organic Geochemical Characteristics Of Black Shales Acrossmentioning

confidence: 99%

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

View full text Add to dashboard Cite

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.

show abstract

Stratigraphic and Earth System approaches to defining the Anthropocene

et al. 2016

View full text Add to dashboard Cite

Stratigraphy provides insights into the evolution and dynamics of the Earth System over its long history. With recent developments in Earth System science, changes in Earth System dynamics can now be observed directly and projected into the near future. An integration of the two approaches provides powerful insights into the nature and significance of contemporary changes to Earth. From both perspectives, the Earth has been pushed out of the Holocene Epoch by human activities, with the mid-20th century a strong candidate for the start date of the Anthropocene, the proposed new epoch in Earth history. Here we explore two contrasting scenarios for the future of the Anthropocene, recognizing that the Earth System has already undergone a substantial transition away from the Holocene state. A rapid shift of societies toward the UN Sustainable Development Goals could stabilize the Earth System in a state with more intense interglacial conditions than in the late Quaternary climate regime and with little further biospheric change. In contrast, a continuation of the present Anthropocene trajectory of growing human pressures will likely lead to biotic impoverishment and a much warmer climate with a significant loss of polar ice.

show abstract

A sulfidic driver for the end-Ordovician mass extinction

Cited by 188 publications

References 99 publications

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

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

Stratigraphic and Earth System approaches to defining the Anthropocene

Contact Info

Product

Resources

About