(Table 1) Sample levels of diatom and silicoflagellate datums at DSDP Holes 69-504 and 69-505
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| Natura: | Dataset Open Access |
| Lingua: | en |
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PANGAEA
1983
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| _version_ | 1867169083185692672 |
|---|---|
| author | Sancetta, Constance A |
| author_facet | Sancetta, Constance A |
| collection | Datos científicos de ciencias marinas y ambientales |
| contents | A standard biostratigraphic system, based upon diatom datum levels previously correlated to the paleomagnetic record, was applied to Deep Sea Drilling Project Sites 501/504 and 505. Sedimentation appears to have been constant at the three sites, averaging 50 m/m.y. at Sites 501/504 and 60 m/m.y. at Site 505. Calcium carbonate is rather poorly preserved at both sites, because of depth of water and, at Sites 501/504, alteration by diagenesis. Siliceous microfossils are common and moderately well preserved at the three sites; at Sites 501/504, diatoms disappear abruptly below the first occurrence of chert. The uppermost Miocene diatom assemblage occurs just above chert and is characterized by a strong dominance of Thalassionema and Thalassiothrix, which implies very high silica production during the latest Miocene; the chert probably is derived from a similar assemblage. In the earliest Pliocene, silica production appears to have decreased sharply; about 3 Ma, preservation of calcium carbonate also diminished, suggesting a shoaling of the CCD. At 2 Ma, there occurred a short interval of low production of both calcium carbonate and silica, which lasted into the earliest Pleistocene. |
| format | Dataset Open Access |
| id | pangaea_https___doi_org_10_1594_PANGAEA_816189 |
| institution | PANGAEA |
| language | en |
| publishDate | 1983 |
| publisher | PANGAEA |
| record_format | pangaea |
| spellingShingle | (Table 1) Sample levels of diatom and silicoflagellate datums at DSDP Holes 69-504 and 69-505 Sancetta, Constance A 69-504; 69-505; Ageprofile Datum Description; Deep Sea Drilling Project; DRILL; Drilling/drill rig; DSDP; DSDP/ODP/IODP sample designation; Event label; Glomar Challenger; Leg69; North Pacific/GRABEN; Sample code/label A standard biostratigraphic system, based upon diatom datum levels previously correlated to the paleomagnetic record, was applied to Deep Sea Drilling Project Sites 501/504 and 505. Sedimentation appears to have been constant at the three sites, averaging 50 m/m.y. at Sites 501/504 and 60 m/m.y. at Site 505. Calcium carbonate is rather poorly preserved at both sites, because of depth of water and, at Sites 501/504, alteration by diagenesis. Siliceous microfossils are common and moderately well preserved at the three sites; at Sites 501/504, diatoms disappear abruptly below the first occurrence of chert. The uppermost Miocene diatom assemblage occurs just above chert and is characterized by a strong dominance of Thalassionema and Thalassiothrix, which implies very high silica production during the latest Miocene; the chert probably is derived from a similar assemblage. In the earliest Pliocene, silica production appears to have decreased sharply; about 3 Ma, preservation of calcium carbonate also diminished, suggesting a shoaling of the CCD. At 2 Ma, there occurred a short interval of low production of both calcium carbonate and silica, which lasted into the earliest Pleistocene. |
| title | (Table 1) Sample levels of diatom and silicoflagellate datums at DSDP Holes 69-504 and 69-505 |
| topic | 69-504; 69-505; Ageprofile Datum Description; Deep Sea Drilling Project; DRILL; Drilling/drill rig; DSDP; DSDP/ODP/IODP sample designation; Event label; Glomar Challenger; Leg69; North Pacific/GRABEN; Sample code/label |
| url | https://doi.org/10.1594/PANGAEA.816189 |