Meteoroid mayhem in Ole Virginny: Source of the North American tektite strewn field

Poag, C. Wylie; Powars, David S.; Poppe, Lawrence J.; Mixon, Robert B.

doi:10.1130/0091-7613(1994)022<0691:mmiovs>2.3.co;2

Cited by 120 publications

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“…Using the geographic position as well as age and chemical data, previous studies have suggested that the Chesapeake Bay impact structure is the source of the North American tektites (Poag et al 1994;Koeberl et al 1996). Here we report the first Sr-Nd isotope data for samples from the Chesapeake Bay structure, which establish a clear correlation between this impact structure and the 35 Ma tektites and the associated microtektites from the North American strewn field.…”

Section: Discussionmentioning

confidence: 67%

“…The 40 Ar/ 39 Ar step-heating dating on microtektites from Deep Sea Drilling Project (DSDP) site 612, located in offshore New Jersey, USA, yielded 35.2 ± 0.3 Ma and 35.5 ± 0.3 Ma (Obradovich et al 1989), and new data by Horton and Izett (2005) resulted in a weighted mean total fusion 40 Ar/ 39 Ar age of 35.3 ± 0.2 Ma (2σ) for four North American tektites. When seismic data and results from shallow drill cores indicated the presence of an impact structure underneath the Chesapeake Bay at the Atlantic coast of Virginia and Maryland, a connection of the NAT and the North American spherule layer to the Chesapeake Bay impact event was discussed (e.g., Poag et al 1994;Koeberl et al 1996;Glass et al 1998;Montanari and Koeberl 2000;Whitehead et al 2000). Poag et al (2004) assume a diameter of about 85 km for the Chesapeake Bay impact structure, yet such a large size has been questioned by Collins and W¸nnemann (2005), who note that the crater would only be about 45 km in diameter had it formed on land.…”

Section: Late Eocene Impactsmentioning

confidence: 99%

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Establishing the link between the Chesapeake Bay impact structure and the North American tektite strewn field: The Sr-Nd isotopic evidence

Deutsch

Koeberl

2006

Meteoritics &Amp; Planetary Science

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, which is in excellent agreement with previously published data for samples of the NAT strewn field. Target rocks with highly radiogenic Sr isotopic composition, as required for explaining the isotopic characteristics of Deep Sea Drilling Project (DSDP) site 612 tektites, were not among the analyzed sample suite. Based on the new isotope data, we exclude any relation between the NA tektites and the Popigai impact crater, although they have identical ages within 2σ errors. The Chesapeake Bay structure, however, is now clearly constrained as the source crater for the North American tektites, although the present data set obviously does not include all target lithologies that have contributed to the composition of the tektites.

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Section: Discussionmentioning

confidence: 67%

Section: Late Eocene Impactsmentioning

confidence: 99%

Establishing the link between the Chesapeake Bay impact structure and the North American tektite strewn field: The Sr-Nd isotopic evidence

Deutsch

Koeberl

2006

Meteoritics &Amp; Planetary Science

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“…Collapse of this cavity starts at its base and causes a flow of water and rock debris toward the crater center (e.g., Shuvalov 2002). These processes at marinetarget craters may explain the lack of a raised crater rim at the Mjølnir (Tsikalas et al 1998a(Tsikalas et al , 1998bTsikalas and Faleide 2004), Lockne (Sturkell and Lindström 2004), Chesapeake Bay (Poag et al 1994(Poag et al , 2004, and Chicxulub (e.g., Morgan et al 2002a) craters, and the beveled crater rim at Montagnais crater (Jansa et al 1989;Jansa 1993) (cf. Figs.…”

Section: Post-impact Infillingmentioning

confidence: 99%

Post‐impact structural crater modification due to sediment loading: An overlooked process

Tsikalas

Faleide

2007

Meteorit & Planetary Scien

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Abstract-Post-impact crater morphology and structure modifications due to sediment loading are analyzed in detail and exemplified in five well-preserved impact craters: Mjølnir, Chesapeake Bay, Chicxulub, Montagnais, and Bosumtwi. The analysis demonstrates that the geometry and the structural and stratigraphic relations of post-impact strata provide information about the amplitude, the spatial distribution, and the mode of post-impact deformation. Reconstruction of the original morphology and structure for the Mjølnir, Chicxulub, and Bosumtwi craters demonstrates the long-term subsidence and differential compaction that takes place between the crater and the outside platform region, and laterally within the crater structure. At Mjølnir, the central high developed as a prominent feature during post-impact burial, the height of the peak ring was enhanced, and the cumulative throw on the rim faults was increased. The original Chicxulub crater exhibited considerably less prominent peakring and inner-ring/crater-rim features than the present crater. The original relief of the peak ring was on the order of 420-570 m (currently 535-575 m); the relief on the inner ring/crater rim was 300-450 m (currently ∼700 m). The original Bosumtwi crater exhibited a central uplift/high whose structural relief increased during burial (current height 101-110 m, in contrast to the original height of 85-110 m), whereas the surrounding western part of the annular trough was subdued more that the eastern part, exhibiting original depths of 43-68 m (currently 46 m) and 49-55 m (currently 50 m), respectively. Furthermore, a quantitative model for the porosity change caused by the Chesapeake Bay impact was developed utilizing the modeled density distribution. The model shows that, compared with the surrounding platform, the porosity increased immediately after impact up to 8.5% in the collapsed and brecciated crater center (currently +6% due to post-impact compaction). In contrast, porosity decreased by 2-3% (currently −3 to −4.5% due to post-impact compaction) in the peak-ring region. The lateral variations in porosity at Chesapeake Bay crater are compatible with similar porosity variations at Mjølnir crater, and are considered to be responsible for the moderate Chesapeake Bay gravity signature (annular low of −8 mGal instead of −15 mGal). The analysis shows that the reconstructions and the long-term alterations due to post-impact burial are closely related to the impact-disturbed target-rock volume and a brecciated region of laterally varying thickness and depthvarying physical properties. The study further shows that several crater morphological and structural parameters are prone to post-impact burial modification and are either exaggerated or subdued during post-impact burial. Preliminary correction factors are established based on the integrated reconstruction and post-impact deformation analysis. The crater morphological and structural parameters, corrected from post-impact loading and modification effects, can be used to better const...

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“…This mixture has been found in other boreholes in the New Jersey Coastal Plain (Poore and Bybell, 1988) as well as in DSDP (Miller and Hart, 1987) and ODP boreholes (Snyder et al, 1996). It is likely that its deposition is related to a bolide impact postulated by Poag et al (1992Poag et al ( , 1994. The contact separating Sequence E8 from Sequence E9 is sharp at the Island Beach borehole with a medium to coarse pebbly glauconitic, quartzose sand underlain by a slightly sandy clay (Fig.…”

Section: Sequence E8mentioning

confidence: 94%

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

Browning¹,

Miller²,

Fossen³

et al. 1997

Proceedings of the Ocean Drilling Program, 150X Scientific Results

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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.

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Meteoroid mayhem in Ole Virginny: Source of the North American tektite strewn field

Cited by 120 publications

References 0 publications

Establishing the link between the Chesapeake Bay impact structure and the North American tektite strewn field: The Sr-Nd isotopic evidence

Establishing the link between the Chesapeake Bay impact structure and the North American tektite strewn field: The Sr-Nd isotopic evidence

Post‐impact structural crater modification due to sediment loading: An overlooked process

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

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