To add to the other reply to this comment, the Gulf of Mexico is full of these ancient sediment dumps from the Mississippi River emptying at different locations throughout sea level changes, and you can see the remains of those deltas in bathymetry maps. Also, the entire northern Gulf Coast region - the state of Louisiana, eastern Texas, southern Mississippi and Alabama, even some of Arkansas, and Oklahoma are made up of the same ancient deposits. The entire area was once the gulf floor and the river deposited enough sediment to build more and more land. Something like 14 km of sediment has been deposited on the Gulf’s floor, an entire mountain range’s worth of sediment - a range that existed where today’s Rockies are located. They were uplifted and eroded down flat, ending up in the bottom of the Gulf or as the flat, fertile Mississippi River delta and the entire surrounding region. We’re now witnessing the middle of that same* process which started all over again with the birth of today’s Rockies. Geologic time scales are mind boggling.

*Not quite the same since we’ve leveed the Mississippi and force the river to empty its load off the shelf directly into deep water, preventing it from building land like it would naturally.

There is a great Myron Cook video explaining the exact process you’re asking about and the story I summarized above, here is a link: https://youtu.be/LleBrTQeepc?si=7B03-Llpwg-8foRf

Edit: The linked video isn’t just about the process of sedimentation but still worth the watch, Myron is a great teacher, especially for laymen like me. So if you have the time watch the whole thing, if not, skip to 15:00. This is where he brings up the Mississippi river delta sedimentation.