Abyssal benthonic foraminifera as hydrographic indicators in the western South Atlantic Ocean

Lohmann, G. P.

doi:10.2113/gsjfr.8.1.6

Cited by 273 publications

(110 citation statements)

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“…Numerous quantitative core-top studies of benthic foraminiferal distributions have now been conducted in all oceans (Streeter, 1973;Schnitker, 1974;Culp, 1977;Gofas, 1978;Lohmann, 1978;Ingle et al, 1980;Resig, 1981). These studies form a basis for the extrapolation Core-section (interval in cm) 9-3, 20-22 10-2, 20-22 10-2, 120-122 10-3, 70-72 11-2, 20-22 11-2, 70-72 11-2, 120-122 11-3,20-22 11-3, 70-72 12-1, 120-122 12-2, 20-22 12-2, 70-72 12-2, 120-122 12-3, 20-22 12-3, 120- of modern assemblage-water mass relationships into the geologic past.…”

Section: Benthic Foraminifersmentioning

confidence: 99%

“…In order to interpret these assemblage changes in terms of water masses, the Pliocene assemblages must be compared with Recent core top studies. Lohmann (1978Lohmann ( , 1981 studied benthic foraminiferal distributions (>250 µm) from the Rio Grande Rise, and recognized four taxonomically distinct assemblages which coincide with the distribution of subsurface water masses: (1) a Nuttalides umbonifera assemblage (>35OO m) coinciding with AABW; (2) a rmliohá-cibiciá-Oridorsalis assemblage (2100 to 3500 m) coinciding with NADW; (3) a Uvigerina assemblage (1500 to 2200 m) coinciding with CPDW; (4) a Hoeglundina-Globocassidulina assemblage (800 to 1500 m) coinciding with AAIW. Unfortunately, these assemblage-water mass relationships cannot be directly applied to the Site 518 data, owing to a difference in size fraction.…”

Section: Benthic Foraminifersmentioning

confidence: 99%

“…Unfortunately, these assemblage-water mass relationships cannot be directly applied to the Site 518 data, owing to a difference in size fraction. Lohmann (1978Lohmann ( , 1981 collected data at the > 250 µm size fraction, while counts for the Site 518 samples were made at the > 150 µm size fraction. Although the results of Lohmann (1978Lohmann ( , 1981 are not directly applicable, some similarities do exist.…”

Section: Benthic Foraminifersmentioning

confidence: 99%

“…Lohmann (1978Lohmann ( , 1981 collected data at the > 250 µm size fraction, while counts for the Site 518 samples were made at the > 150 µm size fraction. Although the results of Lohmann (1978Lohmann ( , 1981 are not directly applicable, some similarities do exist. The N. umbonifera assemblage of our study (Factor 1) is identical to that of Lohmann's (1978Lohmann's ( , 1981.…”

Section: Benthic Foraminifersmentioning

confidence: 99%

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Climatically Induced Changes in Vertical Water Mass Structure of the Vema Channel during the Pliocene: Evidence from Deep Sea Drilling Project Holes 516A, 517, and 518

Hodell¹,

Kennett²,

Leonard³

1983

Initial Reports of the Deep Sea Drilling Project

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Pliocene changes in the vertical water mass structure of the western South Atlantic are inferred from changes in benthic foraminiferal assemblages and stable isotopes from DSDP Holes 516A, 517, and 518. Factor analysis of 34 samples from Site 518 reveals three distinct benthic foraminiferal assemblages that have been associated with specific subsurface water masses in the modern ocean. These include a Nuttalides umbonifera assemblage (Factor 1) associated with Antarctic Bottom Water (AABW), a Globocassidulina subglobosa-Uvigerina peregrina assemblage (Factor 2) associated with Circumpolar Deep Water (CPDW), and an Oridorsalis umbonatus-Epistominella exigua assemblage associated with North Atlantic Deep Water (NADW). Bathymetric gradients in Δ 13 C between Holes 516A (1313 m), 517 (2963 m), and 518 (3944 m) are calculated whenever possible to monitor the degree of similarity and/or difference in the apparent oxygen utilization (AOU) of water masses located at these depths during the Pliocene. Changes in bathymetric Δ 13 C gradients coupled with benthic foraminiferal assemblages record fundamental changes in the vertical water mass structure of the Vema Channel during the Pliocene from 4.1 to 2.7 Ma.At Site 518, the interval from 4.1 to 3.6 Ma is dominated by the N. umbonifera (Factor 1) and O. umbonatus-E. exigua (Factor 3) assemblages. The Δ 13 C gradient between Holes 518 (3944 m) and 516A (1313 m) undergoes rapid oscillations during this interval though no permanent increase in the gradient is observed. However, δ13 C values at Site 518 are clearly lighter during this interval. These conditions may be related to increased bottom water activity associated with the re-establishment of the West Antarctic Ice Sheet in the late Gilbert Chron (-4.2 to 3.6 Ma) (Osborn et al., 1982).The interval from 3.6 to 3.2 Ma is marked by a dominance of the G. subglobosa-U. peregrina (Factor 2) assemblage and lack of a strong Δ 13 C gradient between Holes 518 (3944 m) and 516A (1313 m). We suggest that shallow circumpolar waters expanded to depths of a least 3944 m (Site 518) during this time.The most profound faunal and isotopic change occurs at 3.2 Ma, and is marked by dominance of the N. umbonifera (Factor 1) and O. umbonatus-E. exigua (Factor 3) assemblages, a l.l‰ enrichment in δ 18 θ, and a large negative increase in the Δ 13 C gradient between Holes 518 and 516A. These changes at Site 518 record the vertical displacement of circumpolar waters by AABW and NADW. This change in vertical water mass structure at 3.2 Ma was probably related to a global cooling event and/or final closure of the Central American seaway. A comparison of the present-day δ 13 C structure of the Vema Channel with a reconstruction between 3.2 and 2.7 Ma indicates that circulation patterns during this late Pliocene interval were similar to those of the modern western South Atlantic.

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Section: Benthic Foraminifersmentioning

confidence: 99%

Section: Benthic Foraminifersmentioning

confidence: 99%

Section: Benthic Foraminifersmentioning

confidence: 99%

Section: Benthic Foraminifersmentioning

confidence: 99%

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Climatically Induced Changes in Vertical Water Mass Structure of the Vema Channel during the Pliocene: Evidence from Deep Sea Drilling Project Holes 516A, 517, and 518

Hodell¹,

Kennett²,

Leonard³

1983

Initial Reports of the Deep Sea Drilling Project

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“…The response of benthic taxa to climatic change, particularly for the North Pacific, is not known at present. The obvious association of benthic foraminifer distributions with water depth alone presently is being reinterpreted in terms of temperature, salinity, and oxygen content; the results (Lohmann, 1978;Streeter and Shackleton, 1978) suggest complicated relationships between species and their environments that can be used to monitor hydrographic changes through time.…”

Section: Site 435mentioning

confidence: 99%

Foraminifers from Deep Sea Drilling Project Sites 434, 435, and 436, Japan Trench

Thompson¹

1980

Initial Reports of the Deep Sea Drilling Project

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Sediments containing foraminifers were penetrated at all three sites drilled during DSDP Leg 56 as the first part of a Japan Trench transect. Two sites were on the inner wall of the trench (Site 435, 3401 m; Site 434, 5986 m), and one was on the oceanic plate east of the trench (Site 436, 5240 m). Because the lysocline in this area is at about 2000 meters and the calcite-compensation depth is at about 3500 meters, calcareous foraminifers are generally not abundant in the sediments; however, the biostratigraphy based upon planktonic foraminifer faunas agrees with that based predominantly upon siliceous microfossils from the sites. Hole 435A yielded the oldest of the planktonic foraminifers from the three sites.Two plankonic foraminifer lineages were particularly important in determining the biostratigraphy of the sites. The Neogloboquadrina asanoi-kagaensis-himiensis-eggeri lineage underwent rapid evolution around the Pliocene-Pleistocene boundary and is widely recognized in the oil-producing region of northern Japan and in the northwest Pacific. Second, the Globorotalia orientalis-inflata praeinflata-inflata inflata lineage evolved during the Pliocene; tests of these species are very resistant to dissolution. During the Pleistocene, individuals of Neogloboquadrina pachyderma preferentially coiled sinistrally in the cold waters north of the subarctic boundary and dextrally in temperate waters south of it. The ratio of these two forms was used to identify relative motions of near-surface waters of the Kuroshio and Oyashio Currents in the transect area in response to Quaternary climatic fluctuations.Benthic foraminifers characteristic of modern surface sediments were used to interpret uplift and plate motions of the Japan Trench as recorded at Leg 56 sites. Materials from the DSDP sites and from piston cores taken elsewhere in the region permitted extension of the foraminifer bathymetry of Matoba (1977) to the bottom of the Japan Trench; the lower bathyal, abyssal, and hadal biofacies are recognized. The sediments of the oceanic plate have a benthic foraminifer fauna distincly different from that of the inner trench wall at comparable depths. There is no evidence from these contrasting faunas to indicate that sediments of the oceanic plate are added to the landward trench wall during subduction.Manganese micronodules recovered from pelagic clay at Site 436 contained external models of Paleogene(?) juvenile planktonic foraminifers. That the tests of these foraminifers did not dissolve before the manganese was deposited is significant to theories of manganesenodule formation.Two new foraminifer species, Globorotalia wilesi and Silicosigmoilina splendida, are named.

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Carbon isotope offsets between benthic foraminifer species of the genus Cibicides (Cibicidoides) in the glacial sub‐Antarctic Atlantic

et al. 2016

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Epibenthic foraminifer δ13C measurements are valuable for reconstructing past bottom water dissolved inorganic carbon δ13C (δ13CDIC), which are used to infer global ocean circulation patterns. Epibenthic δ13C, however, may also reflect the influence of 13C‐depleted phytodetritus, microhabitat changes, and/or variations in carbonate ion concentrations. Here we compare the δ13C of two benthic foraminifer species, Cibicides kullenbergi and Cibicides wuellerstorfi, and their morphotypes, in three sub‐Antarctic Atlantic sediment cores over several glacial‐interglacial transitions. These species are commonly assumed to be epibenthic, living above or directly below the sediment‐water interface. While this might be consistent with the small δ13C offset that we observe between these species during late Pleistocene interglacial periods (Δδ13C = −0.19 ± 0.31‰, N = 63), it is more difficult to reconcile with the significant δ13C offset that is found between these species during glacial periods (Δδ13C = −0.76 ± 0.44‰, N = 44). We test possible scenarios by analyzing Uvigerina spp. δ13C and benthic foraminifer abundances: (1) C. kullenbergi δ13C is biased to light values either due to microhabitat shifts or phytodetritus effects and (2) C. wuellerstorfi δ13C is biased to heavy values, relative to long‐term average conditions, for instance by recording the sporadic occurrence of less depleted deepwater δ13CDIC. Neither of these scenarios can be ruled out unequivocally. However, our findings emphasize that supposedly epibenthic foraminifer δ13C in the sub‐Antarctic Atlantic may reflect several factors rather than being solely a function of bottom water δ13CDIC. This could have a direct bearing on the interpretation of extremely light South Atlantic δ13C values at the Last Glacial Maximum.

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Abyssal benthonic foraminifera as hydrographic indicators in the western South Atlantic Ocean

Cited by 273 publications

References 0 publications

Climatically Induced Changes in Vertical Water Mass Structure of the Vema Channel during the Pliocene: Evidence from Deep Sea Drilling Project Holes 516A, 517, and 518

Climatically Induced Changes in Vertical Water Mass Structure of the Vema Channel during the Pliocene: Evidence from Deep Sea Drilling Project Holes 516A, 517, and 518

Foraminifers from Deep Sea Drilling Project Sites 434, 435, and 436, Japan Trench

Carbon isotope offsets between benthic foraminifer species of the genus Cibicides (Cibicidoides) in the glacial sub‐Antarctic Atlantic

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