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Pacific Coast: Gorgona Island
Gorgona Island (Fig. 46) is located at 3º 51'N, 78º 13'W, about 30 km north of Guapi Bay (Fig. 25). The island is composed mainly of basic and ultra-basic igneous intrusive and extrusive rocks, locally classified as komatiites (Echavarria 1982). The island conforms to the so-called "Igneous complex of Gorgona", dated between 66 and 86 ma (Espinoza et al. 1982). The island is about 9 km long and 2.5 km wide, with a maximum height of 338 m. It is surrounded by Gorgonilla Island and by numerous smaller stacks and keys. These erosional remnants together encompass about 615 km2 (Barrios and Mateo Lopez 2001). The shores of Gorgona are predominantly steep plunging cliffs (Fig. 47) and minor sandy and shingle beaches (Fig. 48) supplied, on its eastern side, by coral reef detritus.
Figure 46. Gorgona and Gorgonilla Islands, view to the north. Reproduced by permission of Observatorio Sismológico del Suroccidente Colombiano (OSSO) - Universidad del Valle. |
Figure 47. Basaltic stack near the northern end of Gorgona Island. Photo by I. Correa. |
Figure 48. Eastern shore of Gorgona Island, with thin sandy-cobble beaches and blocks of basaltic rocks. Photo by I. Correa. |
continue to Malpelo Island
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