The Late Holocene development of St. Joseph Spit

• Other Authors: Rizk, Felix F.
• Format: Others
• Language: English
• Subjects: Geology
• Online Access: http://purl.flvc.org/fsu/lib/digcoll/etd/3087657

Reconstruction of the supratidal history of St. Joseph peninsula was approached on a granulometric, geometric, and internal-structure basis. === Textural and geomorphic evidences supports the hypothesis that the peninsula was integrated from two former barrier islands through subtidal aggradation as well as seaward and lateral progradation. The granulometric characteristics of the platform and subaerial sediment suite suggest a previous history of river and then beach transport. === Salinity-biotopes from benthic foraminifera in the sampled core connote a gradual sea level rise accompanying platform aggradation in the Late Holocene. The terminal stages of this sea level rise were characterized by small-scale fluctuations. === The pre-Holocene topography suggests that the Cape San Blas area represents the site of the earliest stages of platform aggradation. The oldest areas on the spit appear to have emerged at least 1,500 years ago. The Cape San Blas tombolo first emerged and hence linked up with Cape Can Blas about 1,000 years ago. Beach ridge growth rates in ridge set "nf" suggest 700 years of progradation history north of Eagle Harbor. === Two sediment sources were inferred from this study: Cape San Blas and Bell shoal. === Transverse transport was more important earlier in the history of the spit, but littoral drift later became dominant. North of Eagle Harbor, the spit developed under decreasing wave energy conditions. === Beach ridge origin on St. Joseph spit based on internal structure alone is equivocal. Both eolian and non-eolian strata were observed although the latter were more widespread. === Certain previous work has also shown the internal structure of ridges can form by vegetative trapping. === On the backshore of prograding beaches where the subaerial stages of beach ridge history begins, eolian and swash strata are inseparable. Beach ridges are therefore considered to be examples of convergent landforms, evolving initially from swash overtopping during elevated water levels. === Some of the eolian traits appear to come from pulses of eolian settling of "dust" as indicated by the tail-of-fines. === The standard deviation and the tail-of-fines were the most diagnostic criteria recognizing eolian traits. === In general, sediment in the study area revealed an environmental succession from fluvial to beach and (finally) to dune. === Source: Dissertation Abstracts International, Volume: 52-08, Section: B, page: 4088. === Major Professor: William Tanner. === Thesis (Ph.D.)--The Florida State University, 1991.