A last glacial to early Holocene fringing reef system on the edge of the Nile littoral cell

Siliciclastic-dominated environments are considered inhospitable for reefs. Yet through glacial cycles, these localities may undergo periods of sediment starvation, which opens the environment for biogenic buildups. The Levant shelf is such an environment, indirectly receiving sediment from the Nile delta. Here, using high-resolution seismic data and targeted coring, a previously unknown, mostly buried, reef system at the edge of the Levant shelf is presented. This reef system, about a kilometer in width, spans most of the Levant shelf with a range of morphologies from mounded to flat top. It represents a lull in the sediment supply to the Levant shelf in the aftermath of the Last Glacial Maximum (LGM). The reef system developed atop an abrasion surface related to the LGM and persisted for several thousand years, during which it transitioned from the euphotic zone to the mesophotic zone. Termination of the reef phase ca. 8 ka coincided with renewal and intensification of sediment supply during the African Humid Period and Sapropel S1. The input of nutrients and sediment during these phases is considered here the kill mechanism. This suite of biogenic buildups represents a prime example of the mode exchange between siliciclastic and carbonate systems.