Was the Richat a lake or wetland within human memory, and if so when?
Three answers, none aheadNone is ahead yet. See what would settle it.
Where it stands
Three answers have been proposed. None is ahead on the evidence yet. Three are still possible.
Why it matters
Plato's Atlantis is a city of rings of water, and proponents say the Richat's rings held water around Plato's date of about 9600 BC. The record of the Sahara's last wet phase, the African Humid Period, says whether and when there was water here, and what kind.
Answers 3
What would settle it
- Search the de Lumley mission reports and later Adrar studies for any dated lake or marsh deposits (diatomite, lacustrine clays, freshwater shell beds) inside the Richat's ring depressions, as opposed to the outer-ring stream alluvium.
- Read the full text of deMenocal et al. 2000 for the dates of the arid Younger Dryas interval at ODP Site 658C, and compare them with the 11,600 years ago the Atlantis case uses; the abstract gives no dates for it.
History
- Herodotus: by the fifth century BC Herodotus knew inner Libya as waterless and rainlessFor: Wet but not a ringed lake: streams and small lakes in the African Humid Period, about 14,800 to 5,500 years ago
- Plato: plato's rings were belts of sea joined to the ocean by a channel, not a lake fed by riversAgainst: Yes: around Plato's date of about 9600 BC, rivers filled the Richat's rings with water
- Plato: plato's date falls inside the African Humid Period, and streams were laying down gravels in the Richat across that spanFor: Yes: around Plato's date of about 9600 BC, rivers filled the Richat's rings with water
- deMenocal et al.: off Mauritania, dust fell to a low between about 14,800 and 5,500 years ago, when the Sahara was green with perennial…For: Wet but not a ringed lake: streams and small lakes in the African Humid Period, about 14,800 to 5,500 years ago
- deMenocal et al.: proponents tie the catastrophe to the Younger Dryas, which off Mauritania was a dry break in the humid periodAgainst: Yes: around Plato's date of about 9600 BC, rivers filled the Richat's rings with water
- deMenocal et al.: plato's date falls inside the African Humid Period, and streams were laying down gravels in the Richat across that spanFor: Yes: around Plato's date of about 9600 BC, rivers filled the Richat's rings with water
- Giresse et al.: plato's date falls inside the African Humid Period, and streams were laying down gravels in the Richat across that spanFor: Yes: around Plato's date of about 9600 BC, rivers filled the Richat's rings with water
- Shanahan et al.: across Africa the humid period lasted about 14,800 to 5,500 years ago and ended earlier in the northFor: Wet but not a ringed lake: streams and small lakes in the African Humid Period, about 14,800 to 5,500 years ago
- Shanahan et al.: plato's date falls inside the African Humid Period, and streams were laying down gravels in the Richat across that spanFor: Yes: around Plato's date of about 9600 BC, rivers filled the Richat's rings with water
- Tierney et al.: leaf waxes off the western Sahara put the Green Sahara at about 11,000 to 5000 years ago, with a likely abrupt endFor: Wet but not a ringed lake: streams and small lakes in the African Humid Period, about 14,800 to 5,500 years ago
- Tierney et al.: one leaf-wax record starts the Green Sahara about 11,000 years ago, after Plato's dateAgainst: Yes: around Plato's date of about 9600 BC, rivers filled the Richat's rings with water
- Novella: proponents tie the catastrophe to the Younger Dryas, which off Mauritania was a dry break in the humid periodAgainst: Yes: around Plato's date of about 9600 BC, rivers filled the Richat's rings with water
- Session 1: found two results bearing on its answers
- Session 2: raised the question, proposed three answers and found ten results bearing on its answers