Benthic foraminifera accumulation rate and benthic foraminiferal productivity proxies at ODP Site 165-999 in the Caribbean (Appendix A)
Fuente:
PANGAEA
Enregistré dans:
| Auteurs principaux: | , |
|---|---|
| Format: | Dataset Open Access |
| Langue: | en |
| Publié: |
PANGAEA
2007
|
| Sujets: | |
| Accès en ligne: | |
| Tags: |
Ajouter un tag
Pas de tags, Soyez le premier à ajouter un tag!
|
| _version_ | 1867168997098651648 |
|---|---|
| author | Jain, Sreepat Collins, Laurel S |
| author_facet | Jain, Sreepat Collins, Laurel S |
| collection | Datos científicos de ciencias marinas y ambientales |
| contents | This study tests the hypothesis that the late Miocene to early Pliocene constriction and closure of the Central American Seaway (CAS), connecting the tropical Atlantic and East quatorial Pacific (EEP), caused a decrease in productivity in the Caribbean, due to decreased coastal upwelling and an end to the connection with high-productivity tropical Pacific waters. The present study compared paleoceanographic proxies for the interval between 8.3 and 2.5 Ma in 47 samples from south Caribbean ODP Site 999 with published data on EEP DSDP Site 503. Proxies for Site 999 include the relative abundance of benthic foraminiferal species representing bottom current velocity and the flux of organic matter to the sea floor, the ratio of infaunal/epifaunal benthic foraminiferal species and benthic foraminifer accumulation rates (BFARs). In addition, we calculated % resistant planktic foraminifers species and used the previously published % sand fraction and benthic carbon isotope values from Site 999. During early shoaling of the Isthmus (8.3-7.9 Ma) the Caribbean was under mesotrophic conditions, with little ventilation of bottom waters and low current velocity. The pre-closure interval (7.6-4.2 Ma) saw enhanced seasonal input of phytodetritus with even more reduced ventilation, and enhanced dissolution between 6.8 and 4.8 Ma. During the post-closure interval (4.2-2.5 Ma) in the Caribbean, paleoproductivity decreased, current velocity was reduced, and ventilation improved, while the seasonality of phytodetrital input was reduced dramatically, coinciding with the establishment of the Atlantic-Pacific salinity contrast at 4.2 Ma. Our data support the hypothesis that late Miocene constriction of the CAS at 7.9 Ma and its closure at 4.2 Ma caused a gradual decrease in paleoproductivity in the Caribbean, consistent with decreased current velocity and seasonality of the phytodetrital input. |
| format | Dataset Open Access |
| id | pangaea_https___doi_org_10_1594_PANGAEA_684666 |
| institution | PANGAEA |
| language | en |
| publishDate | 2007 |
| publisher | PANGAEA |
| record_format | pangaea |
| spellingShingle | Benthic foraminifera accumulation rate and benthic foraminiferal productivity proxies at ODP Site 165-999 in the Caribbean (Appendix A) Jain, Sreepat Collins, Laurel S 165-999; Accumulation rate, number of benthic foraminifera; AGE; Benthic foraminifera as eutrophic indicators; Benthic foraminifera as oligotrophic indicators; Calculated (Herguera and Berger, 1991); Caribbean Sea; Cibicidoides wuellerstorfi; COMPCORE; Composite Core; Counting >63 µm fraction; Epistominella exigua; Foraminifera, benthic, epifaunal; Foraminifera, benthic, infaunal; Globocassidulina subglobosa; Infaunal/epifaunal species ratio; Joides Resolution; Leg165; Nuttallides umbonifera; Ocean Drilling Program; ODP; Paleoproductivity as carbon; Size fraction > 0.063 mm, sand This study tests the hypothesis that the late Miocene to early Pliocene constriction and closure of the Central American Seaway (CAS), connecting the tropical Atlantic and East quatorial Pacific (EEP), caused a decrease in productivity in the Caribbean, due to decreased coastal upwelling and an end to the connection with high-productivity tropical Pacific waters. The present study compared paleoceanographic proxies for the interval between 8.3 and 2.5 Ma in 47 samples from south Caribbean ODP Site 999 with published data on EEP DSDP Site 503. Proxies for Site 999 include the relative abundance of benthic foraminiferal species representing bottom current velocity and the flux of organic matter to the sea floor, the ratio of infaunal/epifaunal benthic foraminiferal species and benthic foraminifer accumulation rates (BFARs). In addition, we calculated % resistant planktic foraminifers species and used the previously published % sand fraction and benthic carbon isotope values from Site 999. During early shoaling of the Isthmus (8.3-7.9 Ma) the Caribbean was under mesotrophic conditions, with little ventilation of bottom waters and low current velocity. The pre-closure interval (7.6-4.2 Ma) saw enhanced seasonal input of phytodetritus with even more reduced ventilation, and enhanced dissolution between 6.8 and 4.8 Ma. During the post-closure interval (4.2-2.5 Ma) in the Caribbean, paleoproductivity decreased, current velocity was reduced, and ventilation improved, while the seasonality of phytodetrital input was reduced dramatically, coinciding with the establishment of the Atlantic-Pacific salinity contrast at 4.2 Ma. Our data support the hypothesis that late Miocene constriction of the CAS at 7.9 Ma and its closure at 4.2 Ma caused a gradual decrease in paleoproductivity in the Caribbean, consistent with decreased current velocity and seasonality of the phytodetrital input. |
| title | Benthic foraminifera accumulation rate and benthic foraminiferal productivity proxies at ODP Site 165-999 in the Caribbean (Appendix A) |
| topic | 165-999; Accumulation rate, number of benthic foraminifera; AGE; Benthic foraminifera as eutrophic indicators; Benthic foraminifera as oligotrophic indicators; Calculated (Herguera and Berger, 1991); Caribbean Sea; Cibicidoides wuellerstorfi; COMPCORE; Composite Core; Counting >63 µm fraction; Epistominella exigua; Foraminifera, benthic, epifaunal; Foraminifera, benthic, infaunal; Globocassidulina subglobosa; Infaunal/epifaunal species ratio; Joides Resolution; Leg165; Nuttallides umbonifera; Ocean Drilling Program; ODP; Paleoproductivity as carbon; Size fraction > 0.063 mm, sand |
| url | https://doi.org/10.1594/PANGAEA.684666 |