Strontium-isotopic correlation of Oligocene to Miocene sequences, New Jersey and Florida

Abstract

We use Sr-isotopic age estimates to date siliciclastic, carbonate, and mixed siliciclastic-carbonate Oligocene and Miocene sequences for the New Jersey Coastal Plain and Florida Peninsula and to correlate sequence boundaries with the deep-sea δ 18 O record and the inferred eustatic record of Exxon. The New Jersey onshore Oligocene to lower Miocene sequences correlate reasonably well with the Florida Miocene sequences. However, the majority of middle Miocene sequences mapped in New Jersey are missing from central Florida. The age of Oligocene to Miocene sequence boundaries determined in continuous boreholes from New Jersey, Alabama, and Florida show excellent correlation with deep-sea δ 18 O increases, which are inferred glacioeustatic lowerings. This is strong confirmation that global sea-level change is a primary control on the timing of Oligocene to Miocene sequence boundaries for the coastal plain sections studied here.Whereas global sea level has a significant influence on coastal plain sequences, there are major differences in the preservation of sequences within the same depositional basin (e.g., Salisbury Embayment) and between basins (e.g., Florida basins vs. Salisbury Embayment). These intra-and interbasinal differences must be ascribed to noneustatic processes such as tectonics or differential erosion. Tectonic mechanisms include faulting of crustal blocks, mobile basins with evolving arches and depocenters, local flexural subsidence, or differential subsidence caused by sediment loading.

Early Miocene sequence development across the New Jersey margin

“…Analysis of ODP onshore coreholes drilled at Island Beach, Atlantic City and Cape May established a detailed geochronology of six different lower and lower middle Miocene sequences (Kw0, Kw1a, Kw1b, Kw1c, Kw2a and Kw2b; 24.2–15.6 Myr, Table 1; Sugarman et al , 1997; Miller et al , 1998). Each sequence begins with a basal unconformity covered by a thin TST and a thicker HST.…”

Calcareous plankton bio-chronostratigraphy of the Maltese Lower Globigerina Limestone member

“…All samples in the Lower Globigerina Limestone member provided CLF values consistent with a warm climatic phase which should be related to the Chattian heating documented by the oxygen isotope curve of Miller et al (1987Miller et al ( , 1989Miller et al ( , 1991aMiller et al ( , 1991bMiller et al ( , 2005 Pekar and Miller 1996;Sugarman et al 1997;Shackleton et al 1999;Pekar et al 2002, 2006and Miller et al 2005 and below the beginning of the cooling trend that culminates in the Mi1 event. Based on the studies of Pekar et al (2006) and Raffi et al (2006), it is possible to date the two climatic events at about 25.1 Ma and 23.4 Ma respectively.…”

Ion microprobe measurement of strontium isotopes in calcium carbonate with application to salmon otoliths

“…The following samples were made: 1) Two high-purity, low-Sr (ϳ2 ppm) calcites synthesized from NIST SRM 915a and Specpure CaCO 3 for characterization of Ca-dimer production. 2) Calcite and aragonite synthesized from modern Tridachna shell (EN-1) powder ( 87 Sr/ 86 Sr ratio ϭ 0.709167 Ϯ 0.000016 (Ϯ2 standard error, or 2) (Sugarman et al, 1997). The Sr concentration of the EN-1 powder (1325 ppm) was determined by isotope dilution using thermal ionization mass spectrometry (TIMS) at the Center for Isotope Geochemistry at the University of California, Berkeley (UCB).…”