Late Miocene carbon isotope and paleoproductivity record

We examine whether or not a relationship exists between the late Miocene carbon isotope shift (~7.6-6.6 Ma) and marine productivity at four sites from the Indian and Pacific Oceans (Ocean Drilling Program Sites 721, 1146, 1172, and 846). We use a multiproxy approach based on benthic foraminiferal accumulation rates, elemental ratios, and dissolution indices, and we compare these data to benthic foraminiferal d13C values measured on the same samples. Although some of these sites have been targeted previously in studies of either the late Miocene/early Pliocene "biogenic bloom" (Sites 721 and 846) or the late Miocene carbon isotope shift (Site 1172), our records are the first to establish paired proxy records of carbon isotopes and paleoproductivity allowing a direct assessment of a potential link. Our results indicate that at all sites, productivity increased sometime during the d13C shift; at three sites (721, 1146, and 846), productivity increased at the beginning of the shift. The correlation coefficients derived from linear regression between micropaleontologically derived productivity and foraminiferal d13C values are relatively high during the time interval containing the late Miocene d13C shift (and statistically significant at three of the sites). Carbon flux and isotope mass balance considerations illustrate that transfer of organic matter between the terrestrial and marine reservoirs together with enhanced oceanic upwelling best approximates observed changes in carbon isotope records and paleoproductivity. We note that long-term trend in the Site 846 paleoproductivity record can be correlated to the long-term trend in the Site 848 eolian flux reconstructions of Hovan (1995, doi:10.2973/odp.proc.sr.138.132.1995) hinting at a link between strengthened wind regime and productivity during the late Miocene.

Age model, stable isotopes, major element proportions and endmember unmixing results from four western tropical Atlantic cores

We investigate changes in the delivery and oceanic transport of Amazon sediments related to terrestrial climate variations over the last 250 ka. We present high-resolution geochemical records from four marine sediment cores located between 5 and 12° N along the northern South American margin. The Amazon River is the sole source of terrigenous material for sites at 5 and 9° N, while the core at 12° N receives a mixture of Amazon and Orinoco detrital particles. Using an endmember unmixing model, we estimated the relative proportions of Amazon Andean material ("%-Andes", at 5 and 9° N) and of Amazon material ("%-Amazon", at 12° N) within the terrigenous fraction. The %-Andes and %-Amazon records exhibit significant precessional variations over the last 250 ka that are more pronounced during interglacials in comparison to glacial periods. High %-Andes values observed during periods of high austral summer insolation reflect the increased delivery of suspended sediments by Andean tributaries and enhanced Amazonian precipitation, in agreement with western Amazonian speleothem records. Increased Amazonian rainfall reflects the intensification of the South American monsoon in response to enhanced land-ocean thermal gradient and moisture convergence. However, low %-Amazon values obtained at 12° N during the same periods seem to contradict the increased delivery of Amazon sediments. We propose that reorganizations in surface ocean currents modulate the northwestward transport of Amazon material. In agreement with published records, the seasonal North Brazil Current retroflection is intensified (or prolonged in duration) during cold substages of the last 250 ka (which correspond to intervals of high DJF or low JJA insolation) and deflects eastward the Amazon sediment and freshwater plume.

Carbon and oxygen isotopic composition of benthic foraminifers from ODP Leg 167 sites

Three sites, drilled during Ocean Drilling Program (ODP) Leg 167, were chosen for detailed late Pleistocene paleoceanographic studies of intermediate water along the California margin. These sites are Site 1011 (Animal Basin, 31°17'N, 117°38'W, 2033 m water depth, 1600 m sill depth), Site 1012 (East Cortez Basin, 32°17'N, 118°23'W, 1783 m water depth, 1415 m sill depth), and Site 1018 (Guide Seamount, 36°59'N, 123°17'W, 2476 m water depth). Here we present carbon and oxygen isotopic measurements of benthic foraminifers from these three sites. We made 135 measurements from Site 1011, 387 measurements from Site 1012, and 231 measurements from Site 1018. This data report includes an explanation of the methods used to generate these isotopic records and the age models for each site. Detailed paleoceanographic interpretations of the isotopic records are currently under way.

Stable isotope record of foraminifera from the subarctic Pacific

Benthic (Uvigerina spp., Cibicidoides spp., Gyroidinoides spp.) and planktonic (N. pachyderma sinistral, G. bulloides) stable isotope records from three core sites in the central Gulf of Alaska are used to infer mixed-layer and deepwater properties of the late glacial Subarctic Pacific. Glacial-interglacial amplitudes of the planktonic delta18O records are 1.1-1.3 per mil, less than half the amplitude observed at core sites at similar latitudes in the North Atlantic; these data imply that a strong, negative deltaw anomaly existed in the glacial Subarctic mixed layer during the summer, which points to a much stronger low-salinity anomaly than exists today. If true, the upper water column in the North Pacific would have been statically more stable than today, thus suppressing convection even more efficiently. This scenario is further supported by vertical (i.e., planktic versus benthic) delta18O and delta13C gradients of >1 per mil, which suggest that a thermohaline link between Pacific deep waters and the Subarctic Pacific mixed layer did not exist during the late glacial. Epibenthic delta13C in the Subarctic Pacific is more negative than at tropical-subtropical Pacific sites but similar to that recorded at Southern Ocean sites, suggesting ventilation of the deep central Pacific from mid-latitude sources, e.g., from the Sea of Japan and Sea of Okhotsk. Still, convection to intermediate depths could have occurred in the Subarctic during the winter months when heat loss to the atmosphere, sea ice formation, and wind-driven upwelling of saline deep waters would have been most intense. This would be beyond the grasp of our planktonic records which only document mixed-layer temperature-salinity fields extant during the warmer seasons. Also we do not have benthic isotope records from true intermediate water depths of the Subarctic Pacific.

Oxygen and carbon isotopic composition in Eocene and Oligocene planktonic and benthic foraminifera from DSDP sediments

Oxygen and carbon isotope ratios in Eocene and Oligocene planktonic and benthic foraminifera have been investigated from Atlantic, Indian, and Pacific Ocean locations. The major changes in Eocene-Oligocene benthic foraminiferal oxygen isotopes were enrichment of up to 1 per mil in 18O associated with the middle/late Eocene boundary and the Eocene/Oligocene boundary at locations which range from 1- to 4-km paleodepth. Although the synchronous Eocene-Oligocene 18O enrichment began in the latest Eocene, most of the change occurred in the earliest Oligocene. The earliest Oligocene enrichment in 18O is always larger in benthic foraminifera than in surface-dwelling planktonic foraminifera, a condition that indicates a combination of deep-water cooling and increased ice volume. Planktonic foraminiferal d18O does not increase across the middle/late Eocene boundary at our one site with the most complete record (Deep Sea Drilling Project Site 363, Walvis Ridge). This pattern suggests that benthic foraminiferal d18O increased 40 m.y. ago because of increased density of deep waters, probably as a result of cooling, although glaciation cannot be ruled out without more data. Stable isotope data are averaged for late Eocene and earliest Oligocene time intervals to evaluate paleoceanographic change. Average d18O of benthic foraminifera increased by 0.64 per mil from the late Eocene to the early Oligocene d18O maximum, whereas the average increase for planktonic foraminifera was 0.52 per mil. This similarity suggests that the Eocene/Oligocene boundary d18O increase was caused primarily by increased continental glaciation, coupled with deep sea cooling by as much as 2°C at some sites. Average d18O of surface-dwelling planktonic foraminifera from 14 upper Eocene and 17 lower Oligocene locations, when plotted versus paleo-latitude, reveals no change in the latitudinal d18O gradient. The Oligocene data are offset by ~0.45 per mil, also believed to reflect increased continental glaciation. At present, there are too few deep sea sequences from high latitude locations to resolve an increase in the oceanic temperature gradient from Eocene to Oligocene time using oxygen isotopes.

Geochemistry of middle Eocene-lower Oligocene pelagic sediments of ODP Hole 105-647A

Geochemical analyses of the middle Eocene through lower Oligocene lithologic Unit IIIC (260-518 meters below seafloor [mbsf]) indicate a relatively constant geochemical composition of the detrital fraction throughout this depositional interval at Ocean Drilling Program (ODP) Site 647 in the southern Labrador Sea. The main variability occurs in redox-sensitive elements (e.g., iron, manganese, and phosphorus), which may be related to early diagenetic mobility in anaerobic pore waters during bacterial decomposition of organic matter. Initial preservation of organic matter was mediated by high sedimentation rates (36 m/m.y.). High iron (Fe) and manganese (Mn) contents are associated with carbonate concretions of siderite, manganosiderite, and rhodochrosite. These concretions probably formed in response to elevated pore-water alkalinity and total dissolved carbon dioxide (CO2) concentrations resulting from bacterial sulfate reduction, as indicated by nodule stable-isotope compositions and pore-water geochemistry. These nodules differ from those found in upper Cenozoic hemipelagic sequences in that they are not associated with methanogenesis. Phosphate minerals (carbonate-fluorapatite) precipitated in some intervals, probably as the result of desorption of phosphorus from iron and manganese during reduction. The bulk chemical composition of the sediments differs little from that of North Atlantic Quaternary abyssal red clays, but may contain a minor hydrothermal component. The silicon/ aluminum (Si/Al) ratio, however, is high and variable and probably reflects original variations in biogenic opal, much of which is now altered to smectite and/or opal CT. An increase in the sodium/potassium (Na/K) ratio in the upper Eocene corresponds to the beginning of coarsergrained feldspar flux to the site, possibly marking the onset of more vigorous deep currents. Although the Site 647 cores provide a nearly complete high-resolution, high-latitude Eocene-Oligocene record, the high sedimentation rate and somewhat unusual diagenetic conditions have led to variable alteration of benthic foraminifers and fine-fraction carbonate and have overprinted the original stable-isotope records. Planktonic foraminifers are less altered, but on the whole, there is little chance of sorting out the nature and timing of environmental change on the basis of our stable-isotope analyses.

Stable carbon and oxygen isotope record of planktonic and benthic foraminifera at ODP Site 111-677 in the Panama Basin

Oxygen and carbon isotope ratio measurements are presented for Globigerinoides ruber and for benthic species (mainly Uvigerina spp.) in the Pleistocene and uppermost Pliocene section of ODP Hole 677A in the Panama Basin. This provides the best available continuous Pleistocene stable isotope records from any location, fully justifying the recoring of DSDP Site 504. Oxygen isotope stage 22 (age about 0.85 Ma) was of similar magnitude to the most extensive glacials of the Brunhes and constitutes a logical base for the middle Pleistocene. Oxygen isotope stages as defined by Ruddiman et al. (1986, doi:10.1016/0012-821X(86)90024-5) and by Raymo et al. (1989, doi:10.1029/PA004i004p00413) back to stage 104 are recognized. Although the internationally agreed base of the Quaternary at or near stage 62 (about 1.6 Ma) is not marked by a major isotopic event, it does approximate the base of a regime characterized by highly regular 41,000-yr climate cycles. The records at Site 677 are ideal for time-series analyses and will permit a new attempt to develop a chronology for the early Pleistocene based on tuning to the orbital frequencies. The carbon isotope records also appear to contain considerable variance at orbital frequencies throughout the sequence analyzed.

Oxygen and carbon isotopes from benthic and planktonic foraminifers at DSDP Leg 74 Holes

Oxygen and carbon isotope measurements have been made in picked planktonic and benthonic foraminifers from the five sites drilled on Leg 74, covering the whole Cenozoic. For the Neogene, the coverage gives good information on the development of the vertical temperature structure of Atlantic deep water. For the Paleogene, vertical gradients were weak and it is possible to combine data from different sites to obtain a very detailed record of both the temperature and carbon isotope history of Atlantic deep waters.

Oxygen and carbon isotopes for foraminifers at DSDP Leg 73 Holes

We carried out oxygen and carbon isotope studies on monospecific foraminifer samples from DSDP Sites 522, 523, and 524 of Leg 73 in the central South Atlantic Ocean. The oxygen isotope ratios show a warming of 2 to 3 °C in bottom water and 5°C in surface water during the Paleocene and early Eocene. The carbon isotope values indicate strong upwelling during the early Eocene. The 1% increase in the d18O values of benthic and planktonic foraminifers at Site 523 in the later middle Eocene we ascribe to changes in the pattern of the evaporation and precipitation. The changes may be due to the worldwide Lutetian transgression. The oxygen ratios for the benthic and planktonic foraminifers indicate a cooling at the Eocene/Oligocene transition. The maximum temperature drop (5°C for benthic and 3°C for planktonic foraminifers) is recorded slightly beyond the Eocene/Oligocene boundary and took place over an interval of about 100,000 yr. The pattern of currents in the Southern Hemisphere was mainly structured by a precursor of the subtropical convergence during the Paleocene to late Eocene. The cooling at the Eocene/Oligocene transition led to drastic changes in the circulation pattern, and a precursor of the Antarctic convergence evolved.

Stable isotopc record of ODP Site 114-704

We report a near-continuous, stable isotopic record for the Pliocene-Pleistocene (4.8 to 0.8 Ma) from Ocean Drilling Program Site 704 in the sub-Antarctic South Atlantic (47°S, 7°E). During the early to middle Pliocene (4.8 to 3.2 Ma), variation in delta18O was less than ~0.5 per mil, and absolute values were generally less than those of the Holocene. These results indicate some warming and minor deglaciation of Antarctica during intervals of the Pliocene but are inconsistent with scenarios calling for major warming and deglaciation of the Antarctic ice sheet. The climate System operated within relatively narrow limits prior to ~3.2 Ma, and the Antarctic cryosphere probably did not fluctuate on a large scale until the late Pliocene. Benthic oxygen isotopic values exceeded 3 per mil for the first time at 3.16 Ma. The amplitude and mean of the delta18O signal increased at 2.7 Ma, suggesting a shift in climate mode during the latest Gauss. The greatest delta18O values of the Gaus anti Gilbert chrons occurred at ~2.6 Ma, just below a hiatus that removed the interval from ~2.6 to 2.3 Ma in Site 704. These results agree with those from Subantarctic Site 514, which suggest that the latest Gauss (2.68 to 2.47 Ma) was the time of greatest change in Neogene climate in the northern Antarctic and Subanthtic regions. During this period, surface water cooled as the Polar Front Zone (PFZ) migrated north and perennial sea ice Cover expanded into the Subantarctic region. Antarctic ice volume increased and the ventilation rate of Southern Ocean deep water decreased during glacial events after 2.7 Ma. We suggest that these changes in the Southern Ocean were related to a gradual lowering of sea level and a reduction in the flux of North Atlantic Deep Water (NADW) with the Initiation of ice growth in the northern hemisphere. The early Matuyama Chron (~ 2.3 to 1.7 Ma) was marked by relatively warm climates in the Southern Ocean except for strong glacial events associated with isotopic stages 82 (2.027 Ma), 78 (1.941 Ma), and 70 (1.782 Ma). At 1.67 Ma (stage 65/64 transition), surface waters cooled as the PFZ migrated equatorward and oscillated about a far northerly position for a prolonged interval between 1.67 and 1.5 Ma (stages 65 to 57). Beginning at ~1.42 Ma (stage 52), all parameters (delta18O, delta13C, %opal, %CaCO3) in Hole 704 become highly correlated with each other and display a very strong 41-kyr cyclicity. This increase in the importance of the 41-kyr cycle is attributed to an increase in the amplitude of the Earth's obliquity cycle that was likely reinforced by increased glacial suppression of NADW, which may explain the tightly coupled response that developed between the Southern Ocean and the North Atlantic beginning at ~1.42 Ma (stage 52).

Stable isotopic record of late Pliocene and Pleistocene foraminifera of ODP Site 114-704

We studied the stable isotopic and carbonate stratigraphy of ODP Hole 704A to reconstruct the paleoceanographic evolution of the eastern subantarctic sector of the South Atlantic Ocean. Site 704 is well positioned with respect to latitude (46°52.8'S, 7°25.3'E) and bathymetry (2532 m) to monitor past migrations in the position of Polar Front Zone (PFZ) and changes in deep-water circulation during the late Pliocene-Pleistocene. Several important changes occurred in proxy paleoceanographic indicators across the Gauss/Matuyama boundary at 2.47 Ma: (1) accumulation rates of biogenic sedimentary components increased by an order of magnitude (Froelich et al., this volume); (2) planktonic d1 8O values increased by an average of 0.5 per mil; (3) the amplitude of the benthic d18O signal increased; (4) the accumulation rate of ice-rafted detritus increased several fold (Warnke and Allen, this volume); and (5) carbon isotopic ratios of benthic foraminifers decreased by 0.5 per mil, as did the d13C of the fine-fraction carbonate by 1.5 per mil (Mead et al., 1991, doi:10.2973/odp.proc.sr.114.152.1991), but no change occurred in planktonic foraminiferal d13C values. Most of these changes are consistent with more frequent expansions and contractions of the PFZ over Site 704 after 2.47 Ma, bringing cold, nutrient-rich waters to 47°S that stimulated both carbonate and siliceous productivity. The synchronous increase in d18O values and ice-rafted detritus accumulation in Hole 704A indicates that the 2.4 Ma paleoceanographic event included ice volume growth on both Antarctica and Northern Hemisphere continents. The decrease in benthic d13C values indicates that the ventilation rate of Southern Ocean deep water decreased and the nutrient content increased during glacial events after 2.5 Ma. At the Gauss/Matuyama boundary, benthic d13C values of the Southern Ocean shifted toward those of the Pacific end member, indicating a decrease in the relative mixing ratio of Northern Component Water and Circumpolar Deep Water. During the early Matuyama (~2.3 to 1.7 Ma), the PFZ generally occupied a southerly position with respect to Site 704 and carbonate productivity prevailed. Exceptions to these general conditions occurred during strong glacial events of the early Matuyama (e.g., isotopic stages 82, 78, 74, and 70), when the PFZ migrated to the north and opal sedimentation predominated at Site 704. At 1.7 Ma, the PFZ migrated toward the equator and occupied a more northerly position for a prolonged interval between ~1.7 and 1.5 Ma. Beginning at ~1.5-1.4 Ma, surface and bottom water parameters (d18O, d13C, %CaCO3, and %opal) in the subantarctic South Atlantic became highly correlated such that glacial events (d18O maxima) corresponded to d13C and carbonate minima and opal maxima. This pattern is typical of the correlation found during the latest Pleistocene in the Southern Ocean (Charles and Fairbanks, in press). This event coincided with increased suppression of Northern Component Water during glacial events after 1.5 Ma (Raymo et al., 1990, doi:10.1016/0012-821X(90)90051-X), which may have influenced the climatology of the Southern Hemisphere by altering the flux of heat and salt to the Southern Ocean).

IRD, benthic foraminifera and stable isotopic record of northern Sargasso Sea sediments

New geochemical proxy data from Bermuda Rise piston cores reveal ocean and climate conditions in the northern Sargasso Sea during marine isotope stage 3. Using ?18O on the planktonic foraminifer Globigerinoides ruber, we can correlate explicitly with every stadial/interstadial change in Greenland ice between ~32 and 58 ka. These data suggest repetitive changes of ~4°C in the annual average sea surface temperature (SST), with maximum cooling comparable to or greater than SST during glacial maximum conditions. The extent of SST depression is about the same for typical stadial events and for Heinrich events 4 and 5, which we have identified on the Bermuda Rise by traces of ice rafting. Benthic foraminiferal d13C decreases during every stadial event, consistent with reduced production of the deepest component of North Atlantic Deep Water and shoaling of its interface with Antarctic Bottom Water. This interpretation is supported by benthic Cd/Ca data from the climate cycle associated with interstadial 8.

Age determination of late Quaternary sediment cores from the South Tasman Rise

We use sediment cores from the South Tasman Rise (STR) to reconstruct deep- water circulation in the southwest Pacific sector of the Southern Ocean. Sediment cores MD972106 (45° 09' S, 146° 17' E, 3310 m water depth) and GC34 (45° 06' S, 147° 45' E, 4002 m water depth) preserve records covering the last 160 kyr, with chronology controlled by calibrated accelerator mass spectrometry radiocarbon dates and benthic foraminiferal d18O tied to SPECMAP. The STR benthic foraminiferal d13C records provide new d13C values for Southern Ocean deep water spanning the last 160 kyr at sites unlikely to be affected by variations in productivity. The records establish that glacial benthic foraminifera (Cibicidoides spp.) d13C values are lower relative to interglacial values and are comparable to previous glacial benthic d13C records in the Indian and Pacific sectors of the Southern Ocean. Comparisons of the benthic foraminiferal d13C time series at the STR are made with the equatorial Pacific (V19-30 and Site 846) and the equatorial Atlantic (GeoB1115). The similarity of benthic d13C records at the STR to the equatorial Pacific suggest the Southern Ocean deep-water mass closely tracked those of the deep Pacific, and the presence of a d13C gradient between the STR and the equatorial Atlantic suggests there was continual production of northern source deep water over the past 160 kyr.

Benthic foraminifera and stable isotope composition in Paleocene-Eocene sediments

In the late Paleocene to early Eocene, deep sea benthic foraminifera suffered their only global extinction of the last 75 million years and diversity decreased worldwide by 30-50% in a few thousand years. At Maud Rise (Weddell Sea, Antarctica; Sites 689 and 690, palaeodepths 1100 m and 1900 m) and Walvis Ridge (Southeastern Atlantic, Sites 525 and 527, palaeodepths 1600 m and 3400 m) post-extinction faunas were low-diversity and high-dominance, but the dominant species differed by geographical location. At Maud Rise, post-extinction faunas were dominated by small, biserial and triserial species, while the large, thick-walled, long-lived deep sea species Nuttallides truempyi was absent. At Walvis Ridge, by contrast, they were dominated by long-lived species such as N. truempyi, with common to abundant small abyssaminid species. The faunal dominance patterns at the two locations thus suggest different post-extinction seafloor environments: increased flux of organic matter and possibly decreased oxygen levels at Maud Rise, decreased flux at Walvis Ridge. The species-richness remained very low for about 50 000 years, then gradually increased. The extinction was synchronous with a large, negative, short-term excursion of carbon and oxygen isotopes in planktonic and benthic foraminifera and bulk carbonate. The isotope excursions reached peak negative values in a few thousand years and values returned to pre-excursion levels in about 50 000 years. The carbon isotope excursion was about -2 per mil for benthic foraminifera at Walvis Ridge and Maud Rise, and about -4 per mil for planktonic foraminifera at Maud Rise. At the latter sites vertical gradients thus decreased, possibly at least partially as a result of upwelling. The oxygen isotope excursion was about -1.5 per mil for benthic foraminifera at Walvis Ridge and Maud Rise, -1 per mil for planktonic foraminifera at Maud Rise. The rapid oxygen isotope excursion at a time when polar ice-sheets were absent or insignificant can be explained by an increase in temperature by 4-6°C of high latitude surface waters and deep waters world wide. The deep ocean temperature increase could have been caused by warming of surface waters at high latitudes and continued formation of the deep waters at these locations, or by a switch from dominant formation of deep waters at high latitudes to formation at lower latitudes. Benthic foraminiferal post-extinction biogeographical patterns favour the latter explanation. The short-term carbon isotope excursion occurred in deep and surface waters, and in soil concretions and mammal teeth in the continental record. It is associated with increased CaC03-dissolution over a wide depth range in the oceans, suggesting that a rapid transfer of isotopically light carbon from lithosphere or biosphere into the ocean-atmosphere system may have been involved. The rapidity of the initiation of the excursion (a few thousand years) and its short duration (50 000 years) suggest that such a transfer was probably not caused by changes in the ratio of organic carbon to carbonate deposition or erosion. Transfer of carbon from the terrestrial biosphere was probably not the cause, because it would require a much larger biosphere destruction than at the end of the Cretaceous, in conflict with the fossil record. It is difficult to explain the large shift by rapid emission into the atmosphere of volcanogenic CO2, although huge subaerial plateau basalt eruptions occurred at the time in the northern Atlantic. Probably a complex combination of processes and feedback was involved, including volcanogenic emission of CO2, changing circulation patterns, changing productivity in the oceans and possibly on land, and changes in the relative size of the oceanic and atmospheric carbon reservoirs.

Microfossil, stable isotope, and facies of a near-continuous core from the Gippsland Basin

Fossil, facies, and isotope analyses of an early high-paleolatitude (55°S) section suggests a highly unstable East Antarctic Ice Sheet from 32 to 27 Myr. The waxing and waning of this ice sheet from 140% to 40% of its present volume caused sea level changes of ±25 m (ranging from -30 to +50 m) related to periodic glacial (100,000 to 200,000 years) and shorter interglacial events. The near-field Gippsland sea level (GSL) curve shares many similarities to the far-field New Jersey sea level (NJSL) estimates. However, there are possible resolution errors due to biochronology, taphonomy, and paleodepth estimates and the relative lack of lowstand deposits (in NJSL) that prevent detailed correlations with GSL. Nevertheless, the lateral variations in sea level between the GSL section and NJSL record that suggest ocean siphoning and antisiphoning may have propagated synchronous yet variable sea levels.