Publication Date:
2023-06-27
Description:
A rich, uniquely distributed assemblage (〉80 species) of reworked Paleogene to early Neogene (~66-15 Ma) planktic foraminifera is documented within 〉470 m of late Neogene (~5.7-1.6 Ma) borehole limestone from the Great Bahama Bank west margin. Tests vary in size from 0.13 to 1.0 mm and are unusually well preserved. Where obtainable from the rock, the relict species constitute an estimated 20% to 50% of all taxa. Paleocene faunas occur in upper Miocene host rocks, Eocene species occur in upper Miocene and basal upper Pliocene rocks, and mixed Oligocene and early Miocene taxa occur throughout the section, including the uppermost Pliocene (i.e., the oldest groups disappear successively uphole). Each host-rock interval is separated by major disconformities. This record provides a substantial proxy for: (1) a probable source feature (an epipelagic marine tectonic wall, escarpment, or outcrop composed of pelagic and hemipelagic sediments); (2) a probable tectonically active source area (northern Cuba or southern Bahamas) ; and (3) a variety of events that span 〉60 Myr and have wide-ranging implications, from local (progressive isolation of the oldest faunas), to regional (changes in water depth indicated by the faunas), to global (hiatuses that correlate with one or more major sequence boundaries in the Atlantic, Bahamas, and Gulf of Mexico, as well as proposed eustatic lowstands). Seven unidentified foraminiferal biozones correspond to a proposed early Eocene composite condensed section on the eustatic curve and may have regional implications. The relict faunas also have significant implications for the timing and types of Paleogene and early Neogene sedimentation or nondeposition, sea-level fluctuations, slumping or changing depth of effective marine erosion, and regional late Neogene events that occurred over 4 Myr (age of host rocks).
The direction of the source area from the secondary-emplacement site and the estimated percentages of relict faunas indicate that not all the microfossils in the late Neogene borehole sediments and, by extrapolation therefore, along the entire west margin of the platform, were locally derived. The amount of a possible attendant sedimentary component is not known.
Keywords:
Acarinina broedermanni; Acarinina bullbrooki; Acarinina mckannai; Acarinina pentacamerata; Acarinina spp.; Age, maximum/old; Age, minimum/young; Bahamas; Cassigerinella chipolensis; Catapsydrax dissimilis; Catapsydrax howei; Catapsydrax unicavus; CDRILL; CLINO; Core drilling; DEPTH, sediment/rock; Globigerina, juvenile; Globigerina ampliapertura; Globigerina angiporoides; Globigerina binaiensis; Globigerina bradyi; Globigerina brevis; Globigerina bulloides; Globigerina ciperoensis angulisuturalis; Globigerina ciperoensis angustiumbilicata; Globigerina ciperoensis ciperoensis; Globigerina corpulenta; Globigerina cryptomphala; Globigerina eocaena; Globigerina euapertura; Globigerina foliata; Globigerina gortanii gortanii; Globigerina gortanii praeturritilina; Globigerina helicina; Globigerina inaequispira; Globigerina labiacrassata; Globigerina linaperta; Globigerina ouachitaensis ouachitaensis; Globigerina praebulloides leroyi; Globigerina quinqueloba; Globigerina sellii; Globigerinatella insueta; Globigerinatheka index index; Globigerinatheka index rubriformis; Globigerinatheka index tropicalis; Globigerinatheka subconglobata euganea; Globigerina triloculinoides; Globigerina tripartita; Globigerina woodi connecta; Globigerina woodi woodi; Globigerina yeguaensis; Globigerinita incrusta; Globigerinita naparimaensis; Globigerinoides bisphericus; Globigerinoides diminutus; Globigerinoides higginsi; Globigerinoides pseudodubia; Globigerinoides quadrilobatus altiaperturus; Globigerinoides quadrilobatus primordius; Globigerinoides ruber subquadratus; Globigerinoides trilobus immaturus; Globoconusa daubjergensis; Globorotalia fohsi peripheroronda; Globorotalia increbescens; Globorotalia obesa; Globorotalia opima nana; Globorotalia opima opima; Globorotalia postcretacea; Globorotaloides carcoselleensis; Globorotaloides suteri; Hastigerina bolivariana; Hastigerina cf. bolivariana; Morozovella aequa; Morozovella aragonensis; Morozovella lehneri; Morozovella pseudobulloides; Morozovella spp.; Morozovella uncinata; Neogloboquadrina mayeri; Planorotalites pusillus pusillus; Praeorbulina glomerosa curva; Praeorbulina glomerosa glomerosa; Praeorbulina transitoria; Pseudohastigerina micra; Pseudohastigerina naguewichiensis; Pseudohastigerina wilcoxensis; Truncorotaloides rohri; Truncorotaloides topilensis; Turborotalia cerroazulensis frontosa; Turborotalia cerroazulensis pomeroli; Turborotalia griffinae
Type:
Dataset
Format:
text/tab-separated-values, 860 data points
Permalink
