00readme.html for noaa/glacial

bentonici (benthic): vivono sul fondo degli oceani
planktonici: vivono in superficie, trasportati dalle correnti.

Eemiano: ultimo interglaciale prima dell'Olocene, detto anche MIS 5e.
Il MIS 5c è un Interstadiale, quello di Amersfoort/Brömp.
Il MIS 5a è un Interstadiale, quello di Odderade. Si nota in
particolare nella stratigrafia europea nord occidentale.

Il termine MIS significa:
Marine Isotope Stages.
Gli interglaciali sono identificati da un valore MIS dispari.

Click to enlarge figures.

Past Interglacials Working Group of PAGES (2016), Interglacials of the last 800,000 years,
Rev. Geophys., 54, 162-219, doi:10.1002/2015RG000482.

Abstract: Interglacials, including the present (Holocene) period, are warm, low land ice extent (high sea level), end-members of glacial cycles. Based on a sea level definition, we identify eleven interglacials in the last 800,000 years, a result that is robust to alternative definitions. Data compilations suggest that despite spatial heterogeneity, Marine Isotope Stages (MIS) 5e (last interglacial) and 11c (~400 ka ago) were globally strong (warm), while MIS 13a (~500 ka ago) was cool at many locations. A step change in strength of interglacials at 450 ka is apparent only in atmospheric CO2 and in Antarctic and deep ocean temperature. The onset of an interglacial (glacial termination) seems to require a reducing precession parameter (increasing Northern Hemisphere summer insolation), but this condition alone is insufficient. Terminations involve rapid, nonlinear, reactions of ice volume, CO2 , and temperature to external astronomical forcing. The precise timing of events may be modulated by millennial-scale climate change that can lead to a contrasting timing of maximum interglacial intensity in each hemisphere. A variety of temporal trends is observed, such that maxima in the main records are observed either early or late in different interglacials. The end of an interglacial (glacial inception) is a slower process involving a global sequence of changes. Interglacials have been typically 10-30 ka long.

Somewhere between 1.2 and 0.6 Ma ago, weaker cycles with a period of ~40 ka gave way to stronger (greater isotopic amplitude) cycles with a recurrence period closer to 100 ka. This change is known as the Mid-Pleistocene Transition or Revolution. Its exact date is debated, and it is likely that different aspects of climate shifted into their new mode of operation at different times. By 800 ka ago, the change in amplitude was complete in most records, and glacial cycles with sea level amplitudes of more than 100 m were occurring, mostly with lengths of the order of 100 ka.

Page written: 11.3.2017.         Last updated: 11.3.2017.