(Table 1) Oxygen and carbon isotopes for foraminiferal taxa at DSDP Hole 76-540
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| Natura: | Dataset Open Access |
| Lingua: | en |
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PANGAEA
1984
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| _version_ | 1867171814954762240 |
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| author | Belanger, Paul Matthews, R K |
| author_facet | Belanger, Paul Matthews, R K |
| collection | Datos científicos de ciencias marinas y ambientales |
| contents | We analyzed the oxygen and carbon isotopic composition of planktonic and benthic foraminifers picked from 13 late Eocene to late Oligocene samples from DSDP Site 540 (23°49.73'N, 84°22.25'W, 2926 m water depth) from the Gulf of Mexico. An enrichment occurs in 18O of about 0.5 to 0.8 per mil in both benthic foraminifers and surface-dwelling planktonic foraminifers between the latest Eocene and early Oligocene. This early Oligocene maximum is followed by lower 18O values. A 1.2 per mil d13C decrease in both benthic and planktonic foraminiferal data occurs from the late Eocene to the late Oligocene. There is a correspondence of the 13C signal to deep-sea records; however, the amplitude of this change is greater than previously seen in deep-sea cores, possibly as a result of proximity to terrestrial sources of carbon. The covarying isotopic changes in both benthic and planktonic foraminifers suggest global causes, such as ice volume increases and increased terrestrial carbon input to the ocean. However, during the latter part of the record (early-late Oligocene), the increases in the benthic 18O without accompanying increases observed with planktonic foraminifers suggest that changes in only one part of the system occurred; one potential explanation being a decrease in bottom-water temperatures without concomitant changes in the surface waters. The 18O differences between species of planktonic foraminifers and the difference between planktonic and benthic 18O data indicate that diagenesis problems are minimal. These preliminary results are encouraging given that these cores are partially lithified. |
| format | Dataset Open Access |
| id | pangaea_https___doi_org_10_1594_PANGAEA_809678 |
| institution | PANGAEA |
| language | en |
| publishDate | 1984 |
| publisher | PANGAEA |
| record_format | pangaea |
| spellingShingle | (Table 1) Oxygen and carbon isotopes for foraminiferal taxa at DSDP Hole 76-540 Belanger, Paul Matthews, R K 77-540; Chiloguembelina cubensis, δ13C; Chiloguembelina cubensis, δ18O; Cibicidoides spp., δ13C; Cibicidoides spp., δ18O; Deep Sea Drilling Project; DEPTH, sediment/rock; DRILL; Drilling/drill rig; DSDP; DSDP/ODP/IODP sample designation; Globigerina ampliapertura, δ13C; Globigerina ampliapertura, δ18O; Globigerinatheka spp., δ13C; Globigerinatheka spp., δ18O; Glomar Challenger; Gulf of Mexico; Hantkenina sp., δ13C; Hantkenina sp., δ18O; Hanzawaia cushmani, δ13C; Hanzawaia cushmani, δ18O; Leg77; Mass spectrometer VG Micromass 602; Oridorsalis spp., δ13C; Oridorsalis spp., δ18O; Pseudohastigerina sp., δ13C; Pseudohastigerina sp., δ18O; Sample code/label We analyzed the oxygen and carbon isotopic composition of planktonic and benthic foraminifers picked from 13 late Eocene to late Oligocene samples from DSDP Site 540 (23°49.73'N, 84°22.25'W, 2926 m water depth) from the Gulf of Mexico. An enrichment occurs in 18O of about 0.5 to 0.8 per mil in both benthic foraminifers and surface-dwelling planktonic foraminifers between the latest Eocene and early Oligocene. This early Oligocene maximum is followed by lower 18O values. A 1.2 per mil d13C decrease in both benthic and planktonic foraminiferal data occurs from the late Eocene to the late Oligocene. There is a correspondence of the 13C signal to deep-sea records; however, the amplitude of this change is greater than previously seen in deep-sea cores, possibly as a result of proximity to terrestrial sources of carbon. The covarying isotopic changes in both benthic and planktonic foraminifers suggest global causes, such as ice volume increases and increased terrestrial carbon input to the ocean. However, during the latter part of the record (early-late Oligocene), the increases in the benthic 18O without accompanying increases observed with planktonic foraminifers suggest that changes in only one part of the system occurred; one potential explanation being a decrease in bottom-water temperatures without concomitant changes in the surface waters. The 18O differences between species of planktonic foraminifers and the difference between planktonic and benthic 18O data indicate that diagenesis problems are minimal. These preliminary results are encouraging given that these cores are partially lithified. |
| title | (Table 1) Oxygen and carbon isotopes for foraminiferal taxa at DSDP Hole 76-540 |
| topic | 77-540; Chiloguembelina cubensis, δ13C; Chiloguembelina cubensis, δ18O; Cibicidoides spp., δ13C; Cibicidoides spp., δ18O; Deep Sea Drilling Project; DEPTH, sediment/rock; DRILL; Drilling/drill rig; DSDP; DSDP/ODP/IODP sample designation; Globigerina ampliapertura, δ13C; Globigerina ampliapertura, δ18O; Globigerinatheka spp., δ13C; Globigerinatheka spp., δ18O; Glomar Challenger; Gulf of Mexico; Hantkenina sp., δ13C; Hantkenina sp., δ18O; Hanzawaia cushmani, δ13C; Hanzawaia cushmani, δ18O; Leg77; Mass spectrometer VG Micromass 602; Oridorsalis spp., δ13C; Oridorsalis spp., δ18O; Pseudohastigerina sp., δ13C; Pseudohastigerina sp., δ18O; Sample code/label |
| url | https://doi.org/10.1594/PANGAEA.809678 |