Although optical luminesence dating can be used to date landslide scars in the vicinity of Damieh. that might be a bit like searching for a needle in a haystack so I prefer to concentrate initial efforts in identifying landslide deposits downstream of Damieh. The first step would involve identifying a landslide deposit signature using known events – specifically the earthquakes of 1546 AD and 1927 AD. The seismites from these earthquakes should be identifiable after radiocarbon dating combined with seasonal palynology.
Next comes the (admittedly difficult) task of identifying the landslide deposit. After the dammed water breaks through it will carry the sediment downstream. Since the landlsides are caused by a collapse of soft Plesitocene Lisan formation making up the river banks near Damieh, the key would be to identify reworked Lisan formation landslide deposits from normal Holocene Deposition. Stein et al (1997) examined geochemical differences between the two deposits in order to better understand the evolution of the Dead Sea water body and this work suggests several ways to distinguish the deposits including (but not limited to)
- thin section work
- Micro X Ray Fluorescence scanning to look at Trace Element Geochemistry
- Sr87/Sr86 isotope ratios
- Sr/Ca ratios
Figure 5 from Stein, M., et al. (1997) is reproduced below
Once a landslide deposit “signature” is developed, we can search for landslide deposits in the Exodus time window (~1150 BC – ~1560 BC). Of particular initial interest would be the ~1550 BC Jordan Valley Earthquake that may explain the tilted walls and ash layer Kenyon identified in Jericho at the end of the Middle Bronze age. Jericho was abandoned for many hundreds of years after this event. Thus, this seems to me to be the most promising date to look for the destruction of Jericho.
This is also supported by Josephus who reports that Manetho in writing about Egyptian History (in a text that is now lost and only quoted in other peoples works) states that the Exodus occurred in ~1600 BC and coincided with the expulsion of the Hyksos – a semitic people believed to have come from Canaan who ruled Egypt during the 15th dynasty. 1560 BC is 40 years after 1600 BC.
That said, as Exodus is a confounding enigma, I think the entire potential Exodus time window should be searched without presumption.
Landslide caused by Floods
The 1266 AD damming of the Jordan was caused by flooding and the account in Joshua 3 mentions that the flood waters were high when the natural damming occurred. Hence, it would also be useful to look into a flood signature such as from
- increased amounts of the trace element Mn due to increased dilution of the saline upper water body in the Dead Sea causing a change in the oxidation state of Mn (cite article)
- the Sulfur Cycle (Torfstein, 2008)
- increased aragonite deposition due to an influx of bicarbonates (Stein, 1997)
- palynolgy could also be used since the account in Joshua mentions the time of year (Harvest)