2018-10-16 12:11:26 • ID: 2032
Interconnectivity: On the possible Nature of the MSA in the Murzuq Desert
These are several MSA artifacts from a single find-spot in the Erg Murzuq, rich in non-tanged stone tools. We see a magnificent Bifacial Foliate, bi- and mono-facial points and bifacial scrapers, and of major interest- a 9 cm long backed and arched piece, all better executed than the usual debitage in the Murzuq.
The episodic nature of the Glacial / Interglacial cycles within the Pleistocene is explained by a theory referring to cyclical changes in the Earths circumnavigation of the Sun, as predicted by the Milutin Milankovitch, a Serbian astronomer.
He noted three cyclical changes, that heavily alter the insolation of the Earth, namely:
(1) Earth's eccentricity, with fluctuating orbital shape that ranges between more and less elliptical (0 to 5% ellipticity) on a cycle of about 100 k.a.
(2) Changes in the inclination of the Earths axis (tilt) in relation to its orbit around the Sun. Oscillations in the degree of tilt (between 21.5 to 24.5 degrees), occur on a periodicity of 41.ka.
(3) Cycles is Earth's precession which refers to the Earths slow wobble as it spins on axis. It has a periodicity of 23 k.a.
Regarding N-Africa, the combination of the three cycles had a deep impact on the cyclical desertification and "green Sahara" episodes.
"Insolation changes have driven monsoon dynamics and the periodical onset of humid episodes in North Africa over the last few million years, resulting in the greening of the Sahara and savannah expansion throughout most of the desert at times.
These so-called African humid periods (AHPs) were the consequence of a remarkable transformation of the hydrological cycle over North Africa, related to the intensification of the African summer monsoon in response to increased insolation and subsequent northward migration of the Intertropical Convergence Zone" (Skonieczny et al. 2015.
Reconstruction of the last African Humid Period (AHP) 11–5 k.a. BP, show isolated wetlands, small lakes and perineal rivers but no Megalakes, comparable to the Lake Megachad, in the Sahara, an observation that can be extrapolated to MIS5 and maybe even to the AHPs of Middle Pleistocene age, too.
The evidence for continuous humid corridors and interconnected waterways through the central Sahara may have allowed a north and westward dispersal of hominins originating in other regions of Africa. And in fact- such corridors have been localized in the Murzuq.
If the Murzuq was the recipient area for dispersals, it seems reasonable to take Central /West-Africa and East Africa as source areas into consideration.
Arguing in this way, lithics should have some resemblance to the very variable East African MSA (uni- and bifacial points, backed pieces) and Central/West Africa (mainly bifacial Foliates).
Indeed the artifacts found at "find-spot 43", more than 40 years ago have a Central / East African signature. This holds true for the "Lupemban-like" foliate as to the ached-backed element, which is unusually large, but has for-runners, for example, in the (smaller) MIS5 dated backed pieces, for example from Mumbwa cave .
The quasi absence of tanged pieces in the ensemble and the low frequency of the Levallois-technique fits the hypothesis, that the regional MSA was diversified, with the "Aterian" being only one "facies" (maybe derived from the Nubian complex) in the Lithic record.
Suggested Reading: Milankovitch, M. Kanon der Erdbestrahlungen und seine Anwendung auf das Eiszeitenproblem. Belgrad 1941.
Surf the Blog: see here 1751 , here 2030 , and here 2010
Resources and images in full resolution:
- Image: 2018-10-16_source3.jpg
- Image: 2018-12-02_mursuq4.jpg
- Image: 2018-12-02_muruq6.jpg
- Image: 2018-12-02_mourzuq.jpg
- Extern Link: www.pnas.org…16444.full.pdf
- Extern Link: skepticalscience.com…Milankovitch.html
- Extern Link: www.geo.arizona.edu…Blome_etal_2012.pdf
- Extern Link: www.nature.com…ncomms9751
- Extern Link: www.cambridge.org…7515BC9AAFE40606D3FC30C9D0C7D9D7
- Extern Link: www.pnas.org…458
- Extern Link: www.researchgate.net…258811002_The_Middle_Stone_Age_of_the_Central_Sahara_Biogeographical_opportunities_and_technological_strategies_in_later_human_evolution