Geology topics

James V. Browning

Publications and source records attributed to James V. Browning.

6 recordsLinked to original sources

USGS2024

Holocene foraminifera, climate, and decelerating rise in sea level on the mud patch, southern New England continental shelf

We examined Holocene benthic foraminiferal biofacies, % planktonic foraminifera, and lithofacies changes from New England mud patch cores and present a relative sea-level (RSL) record to evaluate evolution of these rapidly deposited (30–79 cm/kyr) muds. Sandy lower Holocene sections are dominated by Bulimina marginata . The mud patch developed from 11–9 ka as RSL rise slowed from 10 to 7 mm/yr; mud deposition began when the cores (69 to 91 m modern) were inundated below storm wave base. An Elphidium-B. marginata fauna developed at ca. 7–6 ka as RSL rise slowed from approximately 7 to 2 mm/yr. A Globobulimina fauna developed at 3 ka as RSL rise slowed to 1 mm/yr, reflecting lower O 2 conditions. Single specimen δ 18 O analyses of Globobulimina show ∼1‰ variations over the past 3 kyr, reflecting a shelf bottom water seasonal cycle of 4–5°C, and a temperature minimum during the Little Ice Age with warming since.

Journal of Foraminiferal Research↗

USGS2013

Chronology of Eocene-Miocene sequences on the New Jersey shallow shelf: implications for regional, interregional, and global correlations

Integrated Ocean Drilling Program Expedition 313 continuously cored and logged latest Eocene to early-middle Miocene sequences at three sites (M27, M28, and M29) on the inner-middle continental shelf offshore New Jersey, providing an opportunity to evaluate the ages, global correlations, and significance of sequence boundaries. We provide a chronology for these sequences using integrated strontium isotopic stratigraphy and biostratigraphy (primarily calcareous nannoplankton, diatoms, and dinocysts [dinoflagellate cysts]). Despite challenges posed by shallow-water sediments, age resolution is typically ±0.5 m.y. and in many sequences is as good as ±0.25 m.y. Three Oligocene sequences were sampled at Site M27 on sequence bottomsets. Fifteen early to early-middle Miocene sequences were dated at Sites M27, M28, and M29 across clinothems in topsets, foresets (where the sequences are thickest), and bottomsets. A few sequences have coarse (∼1 m.y.) or little age constraint due to barren zones; we constrain the age estimates of these less well dated sequences by applying the principle of superposition, i.e., sediments above sequence boundaries in any site are younger than the sediments below the sequence boundaries at other sites. Our age control provides constraints on the timing of deposition in the clinothem; sequences on the topsets are generally the youngest in the clinothem, whereas the bottomsets generally are the oldest. The greatest amount of time is represented on foresets, although we have no evidence for a correlative conformity. Our chronology provides a baseline for regional and interregional correlations and sea-level reconstructions: (1) we correlate a major increase in sedimentation rate precisely with the timing of the middle Miocene climate changes associated with the development of a permanent East Antarctic Ice Sheet; and (2) the timing of sequence boundaries matches the deep-sea oxygen isotopic record, implicating glacioeustasy as a major driver for forming sequence boundaries.

New Jersey↗

USGS2009

Sea-level rise in New Jersey over the past 5000 years: Implications to anthropogenic changes

We present a mid to late Holocene sea-level record derived from drilling the New Jersey coast that shows a relatively constant rise of 1.8??mm/yr from ~ 5000 to 500 calibrated calendar years before present (yrBP). This contrasts with previous New Jersey estimates that showed only 0.5??mm/yr rise since 2000??yrBP. Comparison with other Mid-Atlantic sea-level records (Delaware to southern New England) indicates surprising uniformity considering different proximities to the peripheral bulge of the Laurentide ice sheet, with a relative rise throughout the region of ~ 1.7-1.9??mm/yr since ~ 5000??yrBP. This regional sea-level rise includes both: 1) global sea-level (eustatic) rise; and 2) far-field geoidal subsidence (estimated as ~ 0.8-1.4??mm/yr today) due to removal of the Laurentide ice sheet and water loading. Correcting for geoidal subsidence, the U.S. east coast records suggest a global sea-level (eustatic) rise of ~ 0.4-1.0??mm/yr (with a best estimate of 0.7 ?? 0.3??mm/yr) since 5000??yrBP. Comparison with other records provides a best estimate of pre-anthropogenic global sea-level rise of < 1.0??mm/yr from 5000 until ~ 200??yrBP. Tide gauge data indicate a 20th century rate of eustatic rise of 1.8??mm/yr, whereas both tide gauge and satellite data suggest an increase in the rate of rise to ~ 3.3??mm/yr from 1993-2006 AD. This indicates that the modern rise (~ 3.3??mm/yr) is significantly higher than the pre-anthropogenic rise (0.7 ?? 0.3??mm/yr). ?? 2008 Elsevier B.V. All rights reserved.

New Jersey↗

USGS2009

Integrated sequence stratigraphy of the postimpact sediments from the Eyreville core holes, Chesapeake Bay impact structure inner basin

The Eyreville core holes provide the first continuously cored record of postimpact sequences from within the deepest part of the central Chesapeake Bay impact crater. We analyzed the upper Eocene to Pliocene postimpact sediments from the Eyreville A and C core holes for lithology (semiquantitative measurements of grain size and composition), sequence stratigraphy, and chronostratigraphy. Age is based primarily on Sr isotope stratigraphy supplemented by biostratigraphy (dinocysts, nannofossils, and planktonic foraminifers); age resolution is approximately ±0.5 Ma for early Miocene sequences and approximately ±1.0 Ma for younger and older sequences. Eocene–lower Miocene sequences are subtle, upper middle to lower upper Miocene sequences are more clearly distinguished, and upper Miocene–Pliocene sequences display a distinct facies pattern within sequences. We recognize two upper Eocene, two Oligocene, nine Miocene, three Pliocene, and one Pleistocene sequence and correlate them with those in New Jersey and Delaware. The upper Eocene through Pleistocene strata at Eyreville record changes from: (1) rapidly deposited, extremely fine-grained Eocene strata that probably represent two sequences deposited in a deep (>200 m) basin; to (2) highly dissected Oligocene (two very thin sequences) to lower Miocene (three thin sequences) with a long hiatus; to (3) a thick, rapidly deposited (43–73 m/Ma), very fine-grained, biosiliceous middle Miocene (16.5–14 Ma) section divided into three sequences (V5–V3) deposited in middle neritic paleoenvironments; to (4) a 4.5-Ma-long hiatus (12.8–8.3 Ma); to (5) sandy, shelly upper Miocene to Pliocene strata (8.3–2.0 Ma) divided into six sequences deposited in shelf and shoreface environments; and, last, to (6) a sandy middle Pleistocene paralic sequence (~400 ka). The Eyreville cores thus record the filling of a deep impact-generated basin where the timing of sequence boundaries is heavily influenced by eustasy.

Virginia↗

USGS1997

Lower to middle Eocene sequences of the New Jersey coastal plain and their significance for global climate change

Boreholes from Island Beach, Allaire, Atlantic City, and Mays Landing, NJ provide an excellent chronology of lower to middle Eocene passive margin sequences and allow analysis of long-term sea-level changes and sedimentation patterns. These New Jersey sequences are tied directly to the geomagnetic polarity time scale through magnetostratigraphy. Integrated stratigraphy (including magnetostratigraphy, lithostratigraphy, plankton biostratigraphy, and benthic foraminiferal biofacies studies) reveals that these sections contain a relatively continuous record of lowermost Eocene to middle Eocene deposition interrupted by short hiatuses. A sequence boundary at the base of the section spans the Paleocene/Eocene boundary, representing a hiatus from 55.8 to 54.7 Ma. A second sequence boundary is associated with a hiatus from 54.0 to 53.4 Ma. A third sequence boundary is associated with a hiatus from 52.9 to 52.3 Ma. Two major unconformities occur near the lower/middle Eocene boundary at all three boreholes. The first represents a hiatus between 50.9 and ~50.5 to 49.9 Ma; the second, between ~49.6 and 48.6 Ma. Early Eocene water depths inferred from benthic foraminiferal biofacies analysis varied from 150 to 200 m and reached their maximum depth between 53.4 and 53.2 Ma. In the middle Eocene, the sedimentation record is less continuous with hiatuses from 48.3 to 47.9 Ma, 46.9 to 44.5 Ma, and 43.4 to ~41.2 Ma. A major lithofacies change from carbonate dominated to siliciclastic dominated occurred by 41.2 Ma. Of the 14 sequences inferred by Exxon for the early to middle Eocene, nine are resolvable on the New Jersey Margin and the remaining five appear to be combined with others. Thus the New Jersey record is consistent with the Exxon record for the early to middle Eocene, although the New Jersey record is better dated. Comparison of the record of sedimentation with the global δ 18 O record shows interesting parallels. It is unlikely that early Eocene sequence boundaries are the result of glacioeustasy because hiatuses from the New Jersey Coastal Plain in this interval do not match increases in the δ 18 O record. In the late middle Eocene, concomitant increases in the planktonic and benthic δ 18 O records coincide with the timing of hiatuses on the New Jersey Coastal Plain. Increases in the δ 18 O records between 43 and 41 Ma coincide with a New Jersey hiatus and a corresponding change in sedimentation type from carbonate dominated to siliciclastic dominated. We conclude that these represent evidence of the first Antarctic ice cap and the beginning of the “Icehouse” world.

New Jersey↗

USGS1997

Upper Eocene sequence stratigraphy and the Absecon Inlet Formation, New Jersey Coastal Plain

We evaluate the age, benthic biofacies, and sequence stratigraphy of thick and well-recovered upper Eocene sediments from the New Jersey Coastal Plain. These strata are herein defined as a lithostratigraphic unit and named the Absecon Inlet Formation. The formation is divided into upper and lower portions. At its type locality in the Atlantic City borehole, the lower portion of the Absecon Inlet Formation consists of 171 ft (52 m) of glauconitic silts and silty clays and is assigned to calcareous nannoplankton Zone NP 19/20 (late Eocene). At the ACGS#4 borehole, the type locality for its upper portion, the formation consists of slightly sandy clays and is assigned to Zone NP 21 (late Eocene to earliest Oligocene). The continuous stratigraphic occurrence of Hantkenina spp. in these sediments is evidence of an Eocene age for the upper portion of the Absecon Inlet Formation. Benthic foraminiferal analysis reveals five biofacies in the Absecon Inlet Formation, three of which can be related to paleowater depth: a Siphonina biofacies inhabited water depths of 75 ± 25 m; a Cibicidoides biofacies inhabited water depths of 100 ± 30 m; and a Globobulimina biofacies inhabited water depths of 125 ± 30 m. In addition, a Gyroidinoides biofacies occurs only within transgressive systems tracts. A Bulimina jacksonensis biofacies is believed to be related to a circum-Atlantic paleoceanographic event unrelated to depth changes on the shelf. Gamma-log, lithologic, and faunal/floral data are used to interpret the sequence stratigraphic architecture of the Absecon Inlet Formation. We conclude that the timing of unconformities (sequence boundaries) and maximum flooding surfaces within the Absecon Inlet Formation is consistent with the eustatic record of Exxon and the global δ 18 O record.

New Jersey↗