Skip to Main Content
Skip Nav Destination

Chaotic, allochthonous, submarine gravity slide deposits (olistostromes) have been reported with increasing frequency during the past 15 yrs in stratigraphic columns throughout the world. One such unit, estimated to be several hundred meters thick, is distributed over 90 sq km in the Puerto Plata area of north-central Dominican Republic.

The gray, clay-sized, structureless matrix of this unit behaves as a quick-clay under shock, and is composed of kaolinite, quartz, montmorillonite, and illite. Pelagic Foraminifera date the matrix as Paleocene(?) or early Eocene(?).

Exotic blocks within the olistostrome include limestone, serpentinite, andesite, pillow volcanics, and tuffaceous rocks. The longest dimensions of the blocks range from 1 cm to 1.5 km, and the known ages range from pre-Paleocene to middle Eocene. Thus, the exotic blocks are older, the same age as, and younger than their enclosing matrix.

The matrix probably was once a marine tuffaceous unit of Paleocene-early Eocene age which was deposited rapidly and retained enough water to liquify spontaneously and to begin moving rapidly down a gentle submarine basin slope following an earthquake shock during the late-middle Eocene. Younger more competent overlying rocks were ruptured and incorporated into the moving mass, while older rocks were torn loose from the submarine slope. The entire unit was emplaced essentially instantaneously into a marine sedimentary sequence.

Although olistostromes record catastrophic events in the geologic record, they do not necessarily imply a major orogeny. However, most described olistostromes were formed during times of tectonic activity. The middle Eocene was such a time in the Puerto Plata area.

You do not currently have access to this chapter.

Figures & Tables





Citing Books via

Close Modal

or Create an Account

Close Modal
Close Modal