Sequence stratigraphy of the arcadia formation, Southeast Florida: an integrated approach

The Arcadia Formation is a mixed carbonate-siliciclastic rock unit that existed as
a shallow carbonate ramp to platform environment during the Late Oligocene to Early
Miocene Epoch. It can be divided into two distinct, informal sections based on
lithological properties: the upper Arcadia Formation and lower Arcadia Formation. The
sections are part of a major, third-order sequence that can be further divided into four
higher-frequency, lower magnitude sequences: ARS1, ARS2, ARS3, and ARS4. The
sequence boundary separating ARS2 and ARS3 represents a drastic change in the
depositional regime from a high-energy, inner ramp/platform to a lower-energy, deep
outer ramp environment. ARS3 represents the period of maximum flooding and
constitutes a major portion of the regressive system tract (RST) of the third order depositional sequence. In certain sections, the Arcadia Formation is heavily bioturbated
including ichnotaxa from the glossifungites, cruziana, and scolithos inchofacies.
Thalassinoides sp. burrows of the glossifungites ichnofacies were found to be commonly
associated with firmground substrates and breaks in sedimentation. The lithofacies
associations were grouped into paleodepositional environments that ranged from
restricted marine to deep outer ramp with lithology ranging from grainstone to
wackestone to mudstone with variable amounts of siliciclastic and phosphatic
constituents. Each sequence boundary extends regionally south from Broward County to
southern Miami-Dade County utilizing gamma-ray geophysical signatures unique to each
sequence.