STRATIGRAPHY OF THE MARGARET CREEK FORMATION, NORTHERN BELIZE

The Margaret Creek formation of northern Belize, is a widely distributed clastic unit of the subsurface of northern Belize. According to previous work, the Margaret Creek formation may range from Upper Jurassic to Lower Cretaceous. The Margaret Creek unconformably overlies the Santa Rosa group (Permian-Carboniferous) and is conformably overlain by the Hill Bank formation, which is regarded as Lower Cretaceous. In the Maya Mountains, some minor fault-bounded blocks, provide limited surface exposures of coarse clastic facies of the Margaret Creek. One of these exposures is located on the main highway at St. Margaret’s Village, Belize, which is the de facto ‘type locality’ of this informal stratigraphic unit. At St. Margaret’s Village, approximately 30 m of the formation is exposed. The stratigraphic section there is comprised of a series of fining upward sequences, which consist typically of a > 1 m thick, channel sand, which is overlain by < 2 m of mottled, overbank clayey sands. These overbank sands are poorly to moderately developed paleosols, as indicated by textural mottling and concentration of pedogenic iron. At the St. Margaret’s Village exposure, there are significant portions of three distinct packages of fining upward deposits, each consisting of several channel sand-overbank sequences. These constituent overbank sequences thicken upward within each package and the terminal paleosol in the package is significantly thicker than the underlying ones. This fluvial stratigraphy is interpreted as a succession of packaged braided stream deposits, which were deposited on the flanks of the then-rising Maya Mountains.