Abstract ref. 

By Barremian-Aptian time, the reef stepped back 40-50 km from the lower Cretaceous margin and formed a long tract of coral-rudist reefs such as the one evident in seismic profiles in the shallow subsurface at the head of Blake Nose (Fig. 3). 

The Aptian reef tract ceased growth during the late Aptian, at which time periplatform debris was no longer delivered to the outer edge of Blake Nose, and the deposition of green and red variegated clays began. 