Ecuador

Introduction

The coastline of Ecuador, including the Galapagos, Puna and Jambeli islands, is about 2,500 km long. The coastal area is divided into two well defined geological regions by the northwest-southeast Chongon-Colonche Range. The northern region is characterised by ranges with horst-like blocks of pyroclastic rocks, basic lavas and dolerites which underlie Cretaceous and Tertiary sediment. The Lower and Middle Cretaceous rocks are largely volcanic deposits, whereas the Upper Cretaceous consists of sands, clays and agglomerates.

The ranges are truncated by the coastline, and as a result, rocky promontories, cliffs and pocket beaches are common features along the coast. South of the Chongon-Colonche Range there is a deep basin covered by thick Tertiary and Quaternary sediment. Intensive block faulting has occurred in the region that is occupied by the Gulf of Guayaquil.

The coastal region is considered to have been unstable since Pleistocene times, and continental uplift is...