Eustatic sea-level and climate changes over the last 600 ka as derived from mollusc-based ESR-chronostratigraphy and pollen evidence in Northern Eurasia

This study investigated the influence of sea-level and climate changes on the decreased fluvial aggradation and subsequent widespread peat initiation in the middle to late-Holocene in the Ishikari lowland, which is a coastal floodplain formed in response to the postglacial sea-level change. By introducing a new approach to separately evaluate the rates of organic and clastic sediment input, we demonstrated that the peat began to form when the fluvial sedimentation rate was significantly decreased (less than 0.6 mm/yr), while plant macrofossil analysis suggested that lowering of water level is also important to the peat initiation. Such changes in sedimentary environment may be associated with the abrupt abandonment of crevasse splays. The concentrated ages of the peat initiation around 5600–5000, 4600–4300, and 4100–3600 cal. BP suggest that an allogenic control promoted the abandonment of crevasse splays, and different onset ages can be explained by different fluvial responses of the Ishikari River and its tributaries. The abandonment of crevasse splays could result from sea-level fall or decreased precipitation. While submillennial sea-level fluctuations coincident with the peat initiation have not been reported in coastal lowlands of Japan, the close comparison of the onset ages and decreased precipitation recorded in a stalagmite from China, which represents the strength of the East Asian summer monsoon (EASM), suggests that decrease in precipitation led to the abandonment of crevasse splays. Our results may indicate that similar fluvial responses might be common in other coastal floodplains affected by the EASM.

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Geomorphic response to sea level and climate changes during Late Quaternary in a humid tropical coastline: Terrain evolution model from Southwest India

PLoS ONE ◽

10.1371/journal.pone.0176775 ◽

2017 ◽

Vol 12 (5) ◽

pp. e0176775 ◽

Cited By ~ 2

Author(s):

Maya K. ◽

Vishnu Mohan S. ◽

Ruta B. Limaye ◽

Damodaran Padmalal ◽

Navnith K. P. Kumaran

Keyword(s):

Sea Level ◽

Climate Changes ◽

Late Quaternary ◽

Evolution Model ◽

Geomorphic Response ◽

Southwest India

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Climate change in the recent geological past and the near future. Predicting its impacts: a Review

Bulletin of the Geological Society of Greece ◽

10.12681/bgsg.20684 ◽

2019 ◽

Vol 55 (1) ◽

pp. 260

Author(s):

Constantinos Perisoratis

Keyword(s):

Climate Change ◽

Sea Level Rise ◽

Climatic Change ◽

Sea Level ◽

Scientific Community ◽

Climate Changes ◽

Late Quaternary ◽

The Earth ◽

Geological Past ◽

Near Future

The climate changes are necessarily related to the increase of the Earth’s temperature, resulting in a sea level rise. Such continuous events, were taking place with minor and greater intensity, during the alternation of warm and cool periods in the Earth during the Late Quaternary and the Holocene periods. However, a particularly significant awareness has taken place in the scientific community, and consequently in the greater public, in the last decades: that a climatic change will take place soon, or it is on-going, and that therefore it is important to undertake drastic actions. However, such a climatic change has not been recorded yet, and hence the necessary actions are not required, for the time being.

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Graptolite dynamics in Silurian and Devonian time

Bulletin of the Geological Society of Denmark ◽

10.37570/bgsd-1986-35-16 ◽

1987 ◽

Vol 35 ◽

pp. 149-159

Author(s):

T. N. Koren'

Keyword(s):

Environmental Factors ◽

Sea Level ◽

Comparative Studies ◽

Climate Changes ◽

Environmental Changes ◽

Time Intervals ◽

Early Devonian ◽

Carbonate Sedimentation ◽

Reference Sections ◽

Devonian Age

On the basis of biostratigraphic data known at present some preliminary attempts are made to evaluate graptolite dynamics, that is changes in graptolite diversity in time and space within pelagic fades of Silurian and Early Devonian age. For the comparative studies of diversity fluctuations versus some major environmental changes a standard graptolite zonation is used. Several critical and more or less well studied stratigraphical intervals are chosen; among them the Ordovician/Silurian, Sheinwoodian/Gorstian and Gorstian/Ludfordian boundary beds. For each level the most complete reference sections are analyzed. Special attention is given to the graptolite extinction, specification and radiation events within these time intervals. They might have been partly connected with or influenced by the environmental factors as a result of eustatic sea-level and climate changes, alteration of anoxic conditions, migration of carbonate sedimentation in pelagic direction, and other globally detectable events. The graptolite evolution during the time of monograptid existence can be subdivided into three phases using the comparison of the amplitude of the extinction-origination events and repeatability of the synphasic cycles.

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INFLUENCE OF THE PALEOCLIMATIC RECONSTRUCTIONS UNCERTAINTY ON THE SUBMARINE PERMAFROST DYNAMICS

Interexpo GEO-Siberia ◽

10.33764/2618-981x-2019-4-1-99-105 ◽

2019 ◽

Vol 4 (1) ◽

pp. 99-105

Author(s):

Valentina Malakhova ◽

Alexey Eliseev

Keyword(s):

Time Series ◽

Sea Level ◽

Air Temperature ◽

Climate Changes ◽

Arctic Shelf ◽

The Arctic ◽

Time Intervals ◽

Ocean Level ◽

Subsea Permafrost ◽

Uncertainty Coefficient

The estimates of the subsea permafrost sensitivity to the uncertainty of paleoclimatic reconstructions of air temperature and ocean level have been obtained. This was done by using the model for thermophysical processes in the subsea sediments and the scenario for climate changes at the Arctic shelf for the last 400 kyr. This model was forced by four time series of temperature at the sediment top, by using different combinations of air temperature and sea level. The uncertainty coefficient of the response of the permafrost base depth is less than 0,3, with the exception of isolated time intervals and / or the deepest areas of the shelf.

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