The Accretion of Gorgona Island, Colombia: Multichannel Seismic Evidence

摘要: Gorgona Island is one of several terranes oceanic rock found in western Colombia and Ecuador. This island on the outer shelf southern composed almost entirely mafic ultramafic rocks best known for its komatiitic lava flows Late Cretaceous age. The tectonic history this unusual block not known. A multichannel seismic reflection profile, collected by Texpet (a subsidiary Texaco, Inc.) 70 km (44 mi) south Island, reveals some details about continental margin area. basement high interpreted to be a continuation high-velocity basement. separated from folded deposits forearc basin landward-dipping thrust fault. fault forms current terrane boundary may original accretion structure block. It unaffected overlying folding has probably been reactivated. thought an extension large northern Colombia, Serrania de Baudo. However, comparison gravity, reflection, structural data two regions suggests that are major break. stratigraphy have accreted before Early Miocene, whereas Baudo was during Miocene-Pliocene as part collision Panama arc with Colombia.