Marine Isotype Stages - a note

 DNA analysis suggests that the descendants of Australia's Aboriginal peoples left Africa perhaps 72,000 years ago. To reach Australia they would have travelled through the Arabian Peninsula. This is a desert area today, difficult to traverse. But was this always so? Were there periods when  the Peninsula was green in whole or part, when the Aboriginal ancestors might have passed? 

A clue here might be provided by Marine isotype stages (MIS). The material that follows is drawn from Wikipedia. 

What are Marine isotype stages?

Quoting:

"Marine isotope stages (MIS), marine oxygen-isotope stages, or oxygen isotope stages (OIS), are alternating warm and cool periods in the Earth's paleoclimate, deduced from oxygen isotope data derived from deep sea core samples. Working backwards from the present, which is MIS 1 in the scale, stages with even numbers have high levels of oxygen-18 and represent cold glacial periods, while the odd-numbered stages are lows in the oxygen-18 figures, representing warm interglacial intervals. The data are derived from pollen and foraminifera (plankton) remains in drilled marine sediment cores, sapropels, and other data that reflect historic climate; these are called proxies."

 The Stages

The following represents the dates etc of some of the stages most relevant to my topic.

Quoting

"The following are the start dates (apart from MIS 5 sub-stages) of the most recent MIS (Lisiecki & Raymo 2005, LR04 Benthic Stack). The figures, in thousands of years ago, are from Lisiecki's website.[13] Numbers for substages in MIS 5 denote peaks of substages rather than boundaries.

MIS     Start date

MIS 1 – 14 kya, end of the Younger Dryas marks the start of the Holocene. The LR04 date of 14 kya had to accommodate less well studied time intervals, and the generally accepted date of 11.7 kya is to be preferred.[14]

MIS 2 – 29 (Last Glacial Maximum)

MIS 3 – 57[a] (MIS 2-4 is called the Last Glacial Period, Wisconsinan glaciation in North America, Weichselian glaciation in northern Europe)

MIS 4 – 71

MIS 5 – 130, usually sub-divided into a to e:

MIS 5a – 82 (peak of interglacial sub-stage)

MIS 5b – 87 (peak of glacial sub-stage)

MIS 5c – 96 (peak of interglacial sub-stage)

MIS 5d – 109 (peak of glacial sub-stage)

MIS 5e – 123 (peak of Last Interglacial, also known as the Eemian among other names)

MIS 6 – 191 (Penultimate Glacial Period, also called Illinoian glacial in North America, later Saalian in northern Europe and later Wolstonian in Britain)

MIS 7 – 243 (Aveley Interglacial in Britain)

MIS 8 – 300 (early Wolstonian in Britain)

MIS 9 – 337 (Purfleet Interglacial in Britain)[16]

MIS 10 – 374

MIS 11 – 424 (Hoxnian Interglacial in Britain, and Holstein Interglacial in Central Europe)"

Comment

If you look at the stages you will see that MIS 4 and 5 are the most relevant to our story. In my next note I will move from the broad stages to look at some of the research relating to the Arabian peninsula to check when the Aboriginal ancestors might have been able to come.