How the Land of Shanghai Was Formed （2/4） How the Land of Shanghai Was Formed （2/4）

Suggestions: • The Geological History of Shanghai • The Shaping of the Land that Became Shanghai

With the (relative) sea level dropping to about 130 meters below today's level, the coastline retreatadvanced to the edge of the East China Sea continental shelf. With the (relative) sea level dropping to about 130 meters below today's level, the coastline advanced to the edge of the East China Sea continental shelf.

The coastline is the edge of the land, so we say it “advances” when the land area increases. I don’t think “relative” is needed here since “below today’s level” is already relative. I would add “to” because it didn’t necessarily drop BY 130 m (we don’t know what the level was before it dropped).

As the {relative sea level rose to about -35 m | sea level rose to about 35 m below today’s level}, the coastline retreated westward to near the Shengsi Islands. As the {relative sea level rose to about -35 m | sea level rose to about 35 m below today’s level}, the coastline retreated westward to near the Shengsi Islands.

It took me a while to figure out what “-35” meant. I would write it out, and omit “relative.” Alternatively, if you’re going to refer to relative sea levels frequently in this series of posts, then you could explain this method of notation by adding it in parentheses after the first instance: “With the sea level dropping to about 130 meters below today's level (-130 m), the coastline retreated….” But doing this will give the sentence a more technical/scientific tone, which might not be what you’re going for.

During this period, early sediment deposition in the Yangtze eEstuary led to the emergence of ancient sandbars, which served as the geological precursors to modern Chongming Island and the southeastern coastal areas of Shanghai. During this period, early sediment deposition in the Yangtze Estuary led to the emergence of ancient sandbars, which served as the geological precursors to modern Chongming Island and the southeastern coastal areas of Shanghai.

Sometimes "Estuary" is capitalized when it is considered part of the proper noun "Yangtze Estuary", but looking it up right now, it seems to be inconsistent. So your original sentence is correct too.

During this period, early sediment deposition in the Yangtze estuary led to the emergence of ancient sandbars, which served as the geological precursors to modern Chongming Island and the southeastern coastal areas of Shanghai. During this period, early sediment deposition in the Yangtze estuary led to the emergence of ancient sandbars, which served as the geological precursors to modern Chongming Island and the southeastern coastal areas of Shanghai.