Early Sea Level Transgressions in the Past 4 MY, Optimum Times for Neritic Carbonate Global Establishment/Growth on Low Latitude Siliciclastic Shelf Edges

Drowned coralgal reefs are commonly observed along the edges of modern low latitude siliciclastic continental shelf (i.e. Gulf of Papua, western Gulf of Mexico). Responding to the initial sea level rise, these coralgal reefs established themselves on top of former lowstand siliciclastic coastal deposits (siliciclastic beach ridges and/or deltas) once the new coast line had migrated further towards land. They first thrived during the early part of the last deglaciation by growing vertically as much as 50 to 70 m but finally drowned not being capable to continuously keep up with the rise of sea level.

This simple scenario for coralgal reef establishment and growth during the last early sea level transgression subsequent to the last Glacial Maximum sea level lowstand, was apparently repeated in the Quaternary during at least three major sea level transgressions that terminated long intervals of significant sea level fall and lowstand, during the Mid-Brunhes (Marine Isotope Stage MIS 12 to 11, about 500 ka; i.e. Great Barrier Reef, Florida Keys, Belize and new Caledonia), and during two other transgressive intervals at about 1.0 and 1.5 Ma (MIS 34 to 31 and MIS 52 to 47, respectively; Gulf of Papua).

During the late Pliocene, several ephemeral phases of neritic carbonate growth are observed on the edges of the Gulf of Papua siliciclastic shelf, at the times when shelf edges were simultaneously prograding and aggrading (relative sea level transgressions). The best developed late Pliocene neritic carbonate edifices on top of shelf edge siliciclastic sediments in the Gulf of Papua seem to have occurred during the transgressions leading to the "mid-Pliocene warm interval" (~3.1 to 2.8 Ma).