There are lots of different studies on measurements of sunken coastlines during different periods in the past. Sometimes groups doing the studies have an agenda, trying to scare people into believing in some sort of fast massive flood. I don’t subscribe to the fear tactics or those doing sunken coastline research with a preconceived notion.
The sunken coastline charts are done on a slow scale of global warming since the Last Glacial Maximum. I realize that there are periods of time where sea levels may have risen slightly faster than other periods of time, but to get the general idea of how the sea levels rose and how coastlines sunk- I focus on slow 10 meter increments.
The most commonly quoted study for sea level rises and sunken coastlines is Lambeck et al. I do not follow nor endorse Lambeck’s results. Lambeck’s group begins their Last Glacial Maximum coast at minus -150 meters which is too deep for the LGM. Then Lambeck’s group contended that Bronze Age sea levels were at minus -5 meters below present, which is nonsense. Roman Empire coastlines were at minus -12 meters to -8 meters below present sea level with known underwater archeological finds in Alexandria and Sicily between minus -12 to -8 meters. Lambeck’s group contended to do some sort of “scientific” measurement to come to the minus -5 meter conclusion at the Bronze Age. But clearly their “science” must have been wrong. Then Lambeck’s group contended that the modern present coastlines existed 2000 years ago. Once again, nonsense. Sea levels have been rising for the last 2000 years and it’s utterly ridiculous that Lambeck’s group claimed “science” when making such a nonsense claim.
So I will not adhere to any results produced by the Lambeck et al study, even if it’s the most cited study on the net.
Last Glacial Maximum Sea Levels
All of my maps place the LGM sea levels at approximately minus -117 meters below present sea level. In the past, I tried different scales. I did do a Beringia Alaska map at minus -125 meters which doesn’t quite fit with the land formations underwater in that region. I have also done minus -100 meter and minus -110 meter maps of the Aegean basin in the past.
But especially when looking at the Aegean Basin, in some regions there’s a clear cut drop off after approximately minus -117 meters. Based on the underwater structure of land, I do acknowledge that in a past freeze, at least 3 to 4 freezes before the last glacial that sea levels dropped below minus -117 meters. I also have noticed (doing many maps of the Aegean and Mediterranean basins) that there appears to be a freeze in the past (maybe at the end of the dinosaur age) when sea levels may have dropped down to minus -150 meters. But I do not see any submerged land formation patterns to suggest that the minus -150 meter drop was recent, nor resembling the last glacial freeze. In addition, land animals crossing to islands at the minus -150 meter mark occurred millions of years before the last glacial and there was no new influx of animals to islands that connected at minus -150 meters at the last glacial. Therefore I conclude that the minus -150 meter drop did not reflect the LGM, but rather a previous freeze millions of years ago.
Late Paleolithic, Mesolithic, to the Younger Dryas
Before the internet was flooded with people quoting the clearly invalid Lambeck study, there was a 2004 research group out of Harvard who came up with the measurment of minus -75 meters at the Younger Dryas and other subsequent researchers came up with similar results.
So I began mapping my Younger Dryas coastline at minus -80 meters and then calculated an even estimate sea level rise between the LGM to the Younger Dryas. The results are as follows:
|Last Glacial Maximum
|-117 meters below present
|-100 meters below present
|-90 meters below present
|-80 meters below present
Early Neolithic to Late Neolithic
When looking at dates for the Neolithic different areas of the world use different time periods to refer to the Neolithic. I’ve conglomerated them into one scale, rather then using the word “neolithic” to give different time periods for different regions of the world. The results are as follows:
|-70 meters below present
|-60 meters below present
|-50 meters below present
Early Bronze Age to Present Sea Levels
Different archeologists use the word “bronze age” to refer to different time periods with differences of thousands of years. And the dates given for “bronze age” vary region by region which can be extremely confusing.
The earliest bronze age finds date to the 4th millenium B.C.E. in the Aegean Sea. However, the rest of the Mediterranean and Atlantic still wasn’t making bronze yet even if some groups in the Aegean were making bronze. Rather than adding to the confusion region by region, I put my maps on one time scale for the bronze age and if a Mediterranean or Atlantic group wasn’t making bronze yet, they still are placed on the Early Bronze Age map for uniformity.
Obviously there are known underwater archeological finds of the Roman Empire between the sea levels of minus -12 meters to minus -8 meters. The Roman built section of Alexandria is submerged beneath the Mediterranean at minus -12 to -8 meters. Favignana, Sicily of the Egadi Islands has a submerged city at minus -12 meters that was destroyed by the Romans.
In the Bay of Cambay, Dwaraka sits between minus -20 meters to minus -40 meters. The dates for the minus -20 meter finds is around 1000 B.C.E. I usually place my “before the Archaic Age” coastline at minus -20 meters for approximately c. 850 B.C.E. which I began doing when it was noted in history that Chios island had separated from the Lydia, Turkey coastline before Ancient Greece. Chios island separates at minus -18 meters.
Also noteworthy, is that the Red Sea floods into the Suez Bay which used to be land at approximately minus -27 meters. Before that there was a fresh water lake in the Suez Bay surrounded by land. Taking into account that the Egyptians would have made dams to stop the Red Sea from flooding backwards into the fresh water Suez Lake, I’m not certain if the minus -27 meter mark is natural or an Egyptian dam that flooded over. Nonetheless, Moses and the Isrealites crossed the Suez Bay when it was land and after the Red Sea flooded the Suez. This was said to occur during the reign of Queen Tiye, but unfortunately there’s a whole range of different alleged carbon dates for Queen Tiye’s reign and a dispute over which mummy was really hers. The earliest dates for Queen Tiye’s mummy is approximately 1800 B.C.E. and the latest dates for Queen Tiye’s mummy is 1450 B.C.E. Either way, it is at the minus -27 meter mark in which the Red Sea floods into the Suez lake and former Suez land region. Therefore, I put all minus -30 meter coastlines at the approximate date of c. 2000 B.C.E.
So the final summary for dates on the maps is as follows:
|Early Bronze Age
|-40 meters below present
|No name timeperiod
|-30 meters below present
|-20 meters below present
|-12 meters below present
|-10 meters below present
- 2 Responses to Timescale
- John Saringer says:
June 23, 2013 at 5:04 pm
Interesting site.. ..congratulations. I’m particularly interested in your map of Sicily to Malta and your assumptions about sea level rises since LGM. I know that there is a great deal of contradiction and inconsistency due to local effects. In your map, have you taken any land movements such as glacial rebound into account? ..reason I ask is that the biggest difference between your predictions and Lambeck seems to be related to glacial rebound. Since the last LGM there have also been as many as 50 major earthquakes in the area.. Comments?
- mapmistress says:
July 28, 2013 at 12:26 pm
The difficulty with the Malta-Ragusa platform maps was there there was no data alike. Every nautical map that I could find of the region gave different measurements. Each one had a completely different line drawn for the 100 meter sea depth mark.
The discrepancies are that no one can seem to agree on the measurements of sea depths of the region. Of the bathymetric charts that I got ahold of, they were vague. Only measuring in bulk of 50 meter increments. And the bathymetric charts differed from the nautical charts. Not really sure why no one agrees on measurements of sea depths for that region. So I did the best I could at compiling the measurements from different nautical charts and bathymetric charts.
Glacial rebound is added into my maps especially on Younger Dryas maps, which was a major glacial rebound. However, for the purposes of the blog, I’m more concerned with focusing on known archeology finds of each timeframe and where humans might have colonized on former coastlines that are now underwater. That means that many times my Younger Dryas maps don’t make it into a blog. Many islands are colonized by boat groups at the late Paleolithic through the Mesolithic (not counting land migration groups). So it’s usually a Mesolithic map that makes the blog rather than a Younger Dryas map of the coastline.
Earthquakes and shifts don’t usually make it. But I do blog about earthquakes changing the coast in several blogs and in some of the blogs I do mention that one plate is sliding under another which could mean a different coastline in the past. It depends on which region I’m referring to. For example, in the Milos blog, I mention that the south coast of Milos might be completely different due to the fact that the south coast sits on a plate that is submerging under another plate. It all depends on the region.