Abstract

The Margaret Creek formation of Belize (Upper Jurassic to Lower Cretaceous [?]) is mainly a clastic unit, which is situated in the Corozal Basin of northern Belize. The Margaret Creek ranges in thickness from zero to approximately 800 ft (243.6 m) in the deeper reaches of the Corozal Basin of northwestern Belize. The Margaret Creek formation at the de facto ‘type locality’ near St. Margaret’s Village is a fluvial deposit, which consists of fining-upward packages of braided stream channel sands that are rich in quartz and feldspar and finer grained overbank deposits. In the subsurface of northern Belize, these facies grade laterally into more marine-influenced deposits, which are rich in clays (including organic-rich clays) and a minor component of carbonates. The fine-grained facies of the Margaret Creek in the deeper reaches of the Corozal Basin has been described as a possible source rock, and recent studies have suggested that the coarser facies situated deep in the basin may be reservoir rocks. The description of the Margaret Creek formation provided here may help illuminate what those coarser reservoir rocks, a target of planned exploration activity, may be like in the subsurface.