Not up on the exact details, but alot of the so called "early" deep water surveys of the ocean floor are done by a ship with the tranducer mounted on the bottom hull of the ship. The sea floor is then pinged, which echos back up to the ship,as the ship makes a gridded pattern sweep of the floor bottom. Thus a profile of the floor bottom is recorded which in appearance looks like a side wall profile of a trench in 2-D. Any abnormal spikes that stand up on the bottom are then gone back over to see what they are, such as a wreck or natural geological formation. This was the early approach, so your mistaken to think that side scan sonar as being "pulled" by a cable. This early technology evolved with the NAVY, looking for subs during the Cold War. With this technology the Ocean Floors where mapped as we know it today. Military technology, and that is where Ballard comes in.
Once you find something on the bottom today, with side scan, it usually is followed up by pulling a sled across it. This takes what looks more like a pictures in 3-D perspective. It's more visually oriented, and can give you a great picture of a ship wreck. This is where Ballard comes in working for the NAVY and Ocean Holes Institute on the U.S. East coast. So bacially there are two types of approaches to bottom survey, doing side scan survey with a ship mounted with a transducer for VERY DEEP water, or pulling a side scan fish in shallow water, say from 300 meter deep to zero depth. Deeper than 300 meter, used the ship mounted tranducer on the hull. Once all that is done, if it's not too deep they pull a sled and acquire a picture. And if it's REAL DEEP a mini sub goes down to take samples and photo like Ballard did on the Titanic. All Ballard knowledge and equipment evolved out from the NAVY, and as this technology began to loose it "High Security" profile, it was given out to the general public to use and study.
Now in the Black Sea, Ballard is in 300 meters and less. He followed the depth at where the coast line was before the Black Sea was filled.
Along the shelf edge and he has recorded wrecks that have varified where the coast line existed before rising water. He also followed up side scan survey with pulling a sled to see what the abnormalities where. And he took samples with a mini sub I believe.
Along the coast of West Louisiana, and East Texas, side scan surveys have been performed for the Oil Company's. Side scan is pulled behind a small vessel. It's shaped usually like a small torpedo, and it's called a "fish." This is all shallow water less than 100 meters. In this particular reference that I now refer to, probably around 20 to 50 meters, side scan survey have found pockets of shell that resemble shell middens along the side of old river channels that once pushed out to the outer continental shelf, before the sea level rose some some 3,000 or 5,000 years ago. This would be all pre-pottery time in the Southeast. So until some coring is done on these possible shell-middens to varify if they are "man made" or natural shell deposits we want know for sure. Coring is the only way to test something on the seafloor at this time. But they are strongly believed to be early shell middens. Both Paleo and Archaic people most certainly where scattered along these early tributaries, these river banks, that extended out to the continental shelf along the Gulf Coast before the sea level rose to what we know it today. We're a long way off from archaeological excavation on the sea floor except in shallow water. Then it has largely been on ship wrecks, with artifacts scattered atop the sea floor, which is gridded off by string, and then sediment is blown away or pumped back up to a ship where it runs through a water sieve. Trowel work of course out of the question. So stratigraphy would need a core sample to be established.
Long point given. Side scan survey can find abnormalities on the floor in the 2-D perspective, like a trench wall profile. But then additional follow up is needed to see what it is in a 3-D perspective. Side scan by itself is not totally conviencing. But it CAN be performed a various depths.
If you need reference to this, I can followed up with that after work.
CHEERS ...
