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Structural and Gravity Transects of the Colon Mountains-Nicaraguan Rise Orogenic Belt of Honduras and Offshore Nicaragua/Jamaica

Abstract

Late Cretaceous northward collision of the Great Arc of the Caribbean with a thin strip of Precambrian-Paleozoic continental rocks led to four distinctive deformed belts observed in outcrop in northern Central America and extending 150 km to the east-northeast beneath the carbonate platform of the Nicaraguan Rise. These deformed belts are identified from outcrop relations described from previous field studies in Central America, and from vintage and modern seismic reflection and gravity data from the Nicaraguan Rise. The belts include: 1) a relatively undeformed continental foreland in northern Central America and the northern Nicaraguan Rise; these rocks have a crustal thickness ranging from 45 km in western Honduras to 30 km at 85W; 2) northwest-verging fold-thrust belt of the Colon Mountains that extends up to 150 km to the northeast and plunges below the Tertiary carbonate cap of the Nicaraguan Rise; these rocks have a crustal thickness of 20-30 km and show an imbricate style of thrusting of late Cretaceous age; 3) Great Arc of the Caribbean or Siuna belt of Nicaragua: these rocks include calc-alkaline volcanic rocks, serpentinite, and ultramafic cumulates of Campanian age (75 Ma) and were deformed by northward thrusting in the late Cretaceous; 4) Caribbean oceanic plateau of Nicaragua and Costa Rica and the area of the Lower Nicaraguan Rise; this little deformed belt has a crustal thickness of 18-20 km and was formed during the Caribbean plume event during the Santonian (88 Ma). Four transects are presented using a combination of 7500 km of seismic and gravity data. Ages are tied to 41 available wells including those from the IODP program. Petroleum implications include: 1) a proven hydrocarbon system at the Main Cape well near the coast of eastern Honduras that formed as an Eocene restricted marine basin in a piggy-back setting on the northward-vergent thrust belt; 2.) a deeper, Cretaceous age, likely gas-prone passive margin play that has been deformed and incorporated into southward-dipping thrust faults formed during the northward transport of the Siuna belt/Great Arc of the Caribbean; and 3) the petroleum potential of the northward-vergent thrust belt is unknown as wells have not penetrated to this depth.