Abstract

Onshore stratigraphy of northern Belize consists of (1) a thick section of deformed and metamorphosed Carboniferous-Permian sedimentary and volcanic strata in the Maya Mountains, (2) a moderately thick section of Mesozoic strata, mostly carbonates, which are found in the subsurface and in outcrop near the Maya Mountains and along major faults, and (3) a relatively thin section of Paleocene-Pleistocene carbonates, which comprise most of the coastal plain of northern Belize. Recently renewed onshore petroleum exploration efforts in central Belize have shown that small-scale anticlinal and fault-related features are important productive petroleum traps in that area. These geologic structures are related to tectonic forces that affected the area beginning mainly during Cretaceous but continuing into Paleogene. The trend in orientation of these structures is north-northeast to south-southwest in the northern and central part of Belize, but the trend changes to more nearly east-northeast to west-southwest as these structures draw near to the Maya Mountains. The petroleum bearing units are the Hill Bank and Yalbac formations, but petroleum may reside in overlying units (Barton Creek and El Cayo carbonates) as well. Petroleum traps at the newly discovered Spanish Lookout Oil Field, and another new oil field nearby, are structural in nature. At this time, Spanish Lookout Oil Field is producing approximately 5000 barrels of oil per day, but may have the potential for perhaps as much as 7000 barrels of oil per day. Seismic, aeromagnetic, and gravity data support the interpretation of similar basement-related, small-scale anticlinal and fault structures in many areas within the main petroleum concessions of central Belize.