Uppermost Campanian–Maestrichtian strontium isotopic, biostratigraphic, and sequence stratigraphic framework of the New Jersey Coastal Plain Peter J. Sugarman New Jersey Geological Survey, CN 427, Trenton, New Jersey 08625, and Department of Geological Sciences, Rutgers University, New Brunswick, New Jersey 08903 Kenneth G. Miller Department of Geological Sciences, Rutgers University, New Brunswick, New Jersey 08903, and Lamont-Doherty Earth Observatory of Columbia University, Palisades, New York 10964 David Bukry U.S. Geological Survey, 345 Middlefield Road, Menlo Park, California 94025 Mark D. Feigenson Department of Geological Sciences, Rutgers University, New Brunswick, New Jersey 08903 ABSTRACT boundaries elsewhere in the Atlantic Recent stratigraphic studies have concen- Coastal Plain (Owens and Gohn, 1985) and trated on the relationships between these se- Firm stratigraphic correlations are the inferred global sea-level record of Haq quences, their bounding surfaces (unconfor- needed to evaluate the global significance of et al. (1987); they support eustatic changes mities), and related sea-level changes. The unconformity bounded units (sequences). as the mechanism controlling depositional shoaling-upward sequences described by We correlate the well-developed uppermost history of this sequence. However, the latest Owens and Sohl (1969) have been related to Campanian and Maestrichtian sequences Maestrichtian record in New Jersey does recent sequence stratigraphic terminology of the New Jersey Coastal Plain to the geo- not agree with Haq et al. (1987); we at- (e.g., Van Wagoner et al., 1988) by Olsson magnetic polarity time scale (GPTS) by in- tribute this to correlation and time-scale (1991) and Sugarman et al. (1993). Glauco- tegrating Sr-isotopic stratigraphy and bio- differences near the Cretaceous/Paleogene nite beds are equivalent to the condensed stratigraphy. To do this, we developed a boundary. High sedimentation rates in the section of Loutit et al. (1988). By definition Maestrichtian (ca. 73–65 Ma) Sr-isotopic latest Maestrichtian of New Jersey (Shrews- (Van Wagoner et al., 1988), these may be- reference section at Deep Sea Drilling bury Member of the Red Bank Formation long to either the late transgressive systems Project Hole 525A in the southeastern At- and the Tinton Formation) suggest tectonic tract or the early highstand systems tract, lantic Ocean. Maestrichtian strata can then uplift and/or rapid progradation during depending on the location of the maximum be dated by measuring their 87Sr/86Sr com- deposition of the highstand systems tract. flooding surface separating the systems position, calibrating to the GPTS of S. C. tracts. It is unclear where the maximum Cande and D. V. Kent (1993, personal com- INTRODUCTION flooding surface is with respect to the glau- mun.), and using the equation Age (Ma) 5 conite sands (i.e., at the base, within, or at 37 326.894 2 52 639.89 (87Sr/86Sr). Sr-strat- Stratigraphic sequences, consisting of ge- the top of the sands), and assignment to igraphic resolution for the Maestrichtian is netically related strata bounded by uncon- transgressive systems tract or highstand sys- estimated as 61.2 to 62 m.y. formities, are well documented for the out- tems tract is equivocal (cf. Fig. 2, columns A At least two unconformity-bounded units cropping Campanian and Maestrichtian and B). The clay-silt and quartz sand facies comprise the uppermost Campanian to beds of the New Jersey Coastal Plain are equivalent to the highstand systems tract Maestrichtian strata in New Jersey. The (Owens and Sohl, 1969). Complete se- (Fig. 2). Lowstand systems tracts have not lower one, the Marshalltown sequence, is quences coarsen and shoal upward, marking been identified in the New Jersey Coastal assigned to calcareous nannofossil Zones vertical transitions from marine-shelf facies Plain, although it is possible that they are CC20/21 (;NC19) and CC22b (;NC20). It to nearshore-marine and nonmarine facies. locally present as incised valley fills, as they ranges in age from ;74.1 to 69.9 Ma based Each sequence is typically a cycle of sedi- are in the Alabama Coastal Plain (Mancini on Sr-isotope age estimates. The overlying mentation consisting of a lower glauconite and Tew, 1993). Navesink sequence is assigned to calcareous sand, a middle clay-silt, and an upper quartz Mapping cyclic sequences on the basis of nannoplankton Zones CC25–26 (;NC21– sand (Figs. 1 and 2). The sequence bound- lithologic characteristics is simple if enough 23); it ranges in age from 69.3 to 65 Ma aries are recognized in outcrop as distinct outcrops and boreholes are available. How- based on Sr-isotope age estimates. The up- surfaces of erosion that commonly have con- ever, when sharp facies changes occur along per part of this sequence, the Tinton For- siderable relief, overlying lag gravels (in- strike or dip, or components of a complete mation, has no calcareous planktonic con- cluding ripup clasts), bioturbation, and dia- sequence are missing due to erosion, non- trol; Sr-isotopes provide an age estimate of genetic cementation by ground water. Unit deposition, or facies change, tracing of for- 66 6 1.2 Ma (latest Maestrichtian). contacts are generally conformable within a mations may be difficult. The problem is Sequence boundaries at the base and the sequence, whereas the sequence boundaries compounded where lithologies are similar top of the Marshalltown sequence match are sharp and unconformable. and thin. For example, additional sequences GSA Bulletin; January 1995; v. 107; no. 1; p. 19–37; 17 figures; 3 tables. 19 SUGARMAN ET AL. Sr-isotope stratigraphy offers another in- dependent means for correlating the Cam- panian-Maestrichtian strata of New Jersey to the GPTS. Sr-isotope stratigraphy re- quires a rapid change in the marine 87Sr/86Sr record and calibration against an independ- ent time variable, which is commonly mag- netostratigraphy (e.g., Miller et al., 1991). Upper Cretaceous Sr-isotope sections have been calibrated with either biostratigraphic, paleomagnetic, or isotopic data in Europe (McArthur et al., 1992a, 1993; N. H. M. Swinburne, A. Montanari, and D. J. De- Paolo, unpubl. data) and the United States western interior (McArthur et al., 1994) and include Campanian to early Maestrichtian Sr data. Additional studies (Martin and Macdougall, 1991; Nelson et al., 1991; McArthur et al., 1992b) have concentrated on the change in 87Sr/86Sr across the Creta- ceous/Paleogene boundary, generating data on the latest Maestrichtian that are cali- brated with biostratigraphic zonations and limited paleomagnetic data (Martin and Macdougall, 1991). In this study, we examine the uppermost Campanian–Maestrichtian sequences in more detail and calibrate them to the GPTS using Sr-isotopes and biostratigraphy. To correlate independently the New Jersey sections to the GPTS, we developed an uppermost Campa- nian–Maestrichtian Sr-isotope reference sec- tion for Deep Sea Drilling Project (DSDP) Figure 1. Generalized stratigraphic column for the outcropping upper Campanian and Hole 525A in the eastern South Atlantic Maestrichtian sediments of the New Jersey Coastal Plain. Molluscan range zones are from (;800 km off the coast of Africa), which con- N. F. Sohl (in Owens et al., 1977, and Owens and Gohn, 1985). Sr-isotope age estimates are tains a reliable magnetostratigraphic record from this study. Differing stage assignments based on foraminifera (foram) and calcareous (Chave, 1984). We also provide new calcare- nannoplankton (nanno) are shown. Tht 5 Hornerstown, S. H. 5 Sandy Hook Member, Kml ous nannoplankton biostratigraphic data from 5 Mount Laurel, Kw 5 Wenonah, Kmt 5 Marshalltown, unc. 5 unconformity, Camp 5 onshore and offshore sections to compare re- Campanian. gional correlations. Integration of Sr-isotopic and biostratigraphic studies of the New Jersey uppermost Campanian–Maestrichtian strata may occur in the subsurface that do not crop rapidly in the Cretaceous, enhancing their allows dating and evaluation of processes out in the New Jersey Coastal Plain (Gohn, value for biostratigraphic correlation, their forming sequences. 1992a; Olsson and Usmani, 1992). succession in the Campanian and Maes- To trace accurately sequences and their trichtian is poorly known (Hancock, 1991). STRATIGRAPHIC SETTING sedimentary facies within a basin, and to Because their zonation is developed for iso- establish interregional correlations, some lated basins, correlations with deep-water Three Campanian and Maestrichtian se- method of chronostratigraphic analysis is re- index fossils is generally difficult, leading quences are examined in this study (Fig. 1). quired. Numerous biostratigraphic studies to uncertainties in integrated chronostrati- Detailed descriptions of these sequences have been undertaken on the Upper Creta- graphic sections. and their corresponding formations appear ceous strata of New Jersey; however, there Radiometric ages based on K/Ar dating in Owens and Sohl (1969) and Owens et al. are still problems correlating this section to of glauconite beds have been established (1970). A brief summary is given here. a standard chronostratigraphy. Planktonic for the Campanian/Maestrichtian strata of The uppermost Campanian sequence, in- index fossils are generally rare, and their New Jersey (Casey, 1964; Owens and Sohl, formally termed the Marshalltown sequence, ranges may be affected by paleoecological 1973; Krinsley, 1973; Obradovich, 1988). includes the Marshalltown, Wenonah, and and paleoclimatologic factors. Calibration Age estimates