The Latest Danian Event (LDE) was a

hyperthermal event A hyperthermal event corresponds to a sudden warming of the planet on a geologic time scale. The consequences of this type of event are the subject of numerous studies because they can constitute an analogue of current global warming. Hypertherma ...

that occurred at the end of the

Danian The Danian is the oldest age or lowest stage of the Paleocene Epoch or Series, of the Paleogene Period or System, and of the Cenozoic Era or Erathem. The beginning of the Danian (and the end of the preceding Maastrichtian) is at the Cretac ...

stage Stage, stages, or staging may refer to: Arts and media Acting * Stage (theatre), a space for the performance of theatrical productions * Theatre, a branch of the performing arts, often referred to as "the stage" * ''The Stage'', a weekly Brit ...

Timing

The LDE is believed to have been

approximately An approximation is anything that is intentionally similar but not exactly equal to something else. Etymology and usage The word ''approximation'' is derived from Latin ''approximatus'', from ''proximus'' meaning ''very near'' and the prefix ' ...

170-230 kyr in duration and occurred about 62.18 Ma. The LDE consisted of two distinct ''δ''¹³C excursions, which are referred to as LDE1 and LDE2, respectively.

Effects

The LDE was similar in essence to the Palaeocene-Eocene Thermal Maximum (PETM), although significantly smaller in magnitude. Seawater warmed by about 2-3 °C in both the surface oceans and the deep oceans. The LDE led to a significant shoaling of the oceanic

lysocline The lysocline is the depth in the ocean dependent upon the carbonate compensation depth (CCD), usually around 5 km, below which the rate of dissolution of calcite increases dramatically because of a pressure effect. While the lysocline is the upp ...

, which is evidenced by the greatly reduced

calcium carbonate Calcium carbonate is a chemical compound with the chemical formula . It is a common substance found in Rock (geology), rocks as the minerals calcite and aragonite, most notably in chalk and limestone, eggshells, gastropod shells, shellfish skel ...

preservation that occurred during the event. Significant

black shale Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of clay minerals (hydrous aluminium phyllosilicates, e.g., kaolin, Al2 Si2 O5( OH)4) and tiny fragments (silt-sized particles) of other minerals, especiall ...

deposition occurred during the LDE, a consequence of sea level rise and clastic starvation combined with enhanced nutrient input into the ocean and anoxia. The planktonic foraminifer

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

''Morozovella'', especially the

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

''M. angulata'', increased in abundance. Sediment core analysis from

Shatsky Rise The Shatsky Rise is Earth's third largest oceanic plateau, (after Ontong Java and Kerguelen) located in the north-west Pacific Ocean east of Japan. It is one of a series of Pacific Cretaceous large igneous provinces (LIPs) together with Hess Ri ...

shows that 40 kyr before LDE1, an increase in

phytodetritus In oceanography, phytodetritus is the organic particulate matter resulting from phytoplankton and other organic material in surface waters falling to the seabed. This process takes place almost continuously as a "marine snow" of descending particles ...

occurred, increasing the abundance of the benthic foraminifer ''Tappanina selmensis''. The start of LDE1 brought about oligotrophic conditions on the seafloor, which continued through LDE2. Unlike the PETM, the LDE did not result in an extinction of benthic foraminifera.

Comparisons with present global warming

As the first global hyperthermal event of the

Cenozoic The Cenozoic Era ( ; ) is Earth's current geological era, representing the last 66million years of Earth's history. It is characterized by the dominance of mammals, insects, birds and angiosperms (flowering plants). It is the latest of three g ...

era An era is a span of time. Era or ERA may also refer to: * Era (geology), a subdivision of geologic time * Calendar era Education * Academy of European Law (German: '), an international law school * ERA School, in Melbourne, Australia * E ...

, the LDE has been interpreted as analogous to present-day anthropogenic global warming. Based on what happened during the LDE, researchers predict the immediate future, in geologic terms, will be characterised by significant ocean acidification and enhanced atmospheric circulation creating a smaller latitudinal temperature gradient.

References

{{Reflist Danian

Timing

Effects

Comparisons with present global warming

See also

References