| _version_ | 1867169979466514432 |
|---|---|
| author | Zepeda, Maybellyn A |
| author_facet | Zepeda, Maybellyn A |
| collection | Datos científicos de ciencias marinas y ambientales |
| contents | Planktonic foraminiferal diversity, equitability and biostratigraphic analysis of samples from Ocean Drilling Program (ODP) Leg 122, Hole 762C show that in general, cool water conditions prevailed during the latest Campanian–Maastrichtian in the eastern Indian Ocean. This is indicated by planktonic foraminiferal assemblages characterized by low species diversity and equitability with abundant rugoglobigerinids and heterohelicids. Archaeoglobigerinids, globigerinelloids, hedbergellids, and long-ranging double-keeled globotruncanids are also present in varying abundance but single-keeled forms occur rarely and sporadically. Identification of the stage and zonal boundaries for the studied geologic interval have been achieved through biostratigraphic analyses of closely spaced samples. Three planktonic foraminiferal biozones were identified, namely; in stratigraphic order, the Heterohelix rajagopalani, Contusotruncana contusa and Abathomphalus mayaroensis Zones. In Hole 762C, a Transitional Realm with Austral influences is defined for the latest Campanian to Maastrichtian, as shown by the high relative abundance of fauna characteristic of Transitional and Austral Realms. Austral endemic species such as Archaeoglobigerina australis Huber and Hedbergella sliteri Huber were found in the samples studied but Globigerinelloides impensus Sliter andA rchaeoglobigerina mateola Huber are conspicuously absent. From the latest Campanian to middle Maastrichtian, cooler parts of the Transitional Realm prevailed. A slight warming trend is assumed towards the end of the middle Maastrichtian because the faunas contain more species indicative of warm water conditions. The late Maastrichtian also appears to have been warmer than the latest Campanian-middle Maastrichtian. This conclusion is based on the high diversity and equitability values and recognition of some thermophilic taxa. A Tethyan influence is inferred for the latest Maastrichtian on the basis of an increase of planktonic foraminiferal species diversity and occurrences of several keeled taxa. |
| format | Dataset Open Access |
| id | pangaea_https___doi_org_10_1594_PANGAEA_755668 |
| institution | PANGAEA |
| language | en |
| publishDate | 1989 |
| publisher | PANGAEA |
| record_format | pangaea |
| spellingShingle | Distribution of foraminiferal fauna from ODP Hole 122-762C (Table 1) Zepeda, Maybellyn A 122-762C; Abathomphalus intermedius; Abathomphalus mayaroensis; Archaeoglobigerina australis; Archaeoglobigerina blowi; Contusotruncana cf. fornicata; Contusotruncana cf. walfischensis; Contusotruncana contusa; Contusotruncana fornicata; Contusotruncana plummerae; Contusotruncana walfischensis; Counting >63 µm fraction; DEPTH, sediment/rock; DRILL; Drilling/drill rig; DSDP/ODP/IODP sample designation; Foraminifera; Foraminifera, benthic; Foraminifera, planktic; Foraminifera, planktic preservation; Globigerinelloides caseyi; Globigerinelloides multispinatus; Globigerinelloides prairiehillensis; Globigerinelloides subcarinatus; Globigerinelloides ultramicrus; Globotruncana aegyptiaca; Globotruncana arca; Globotruncana bulloides; Globotruncana cf. arca; Globotruncana cf. bulloides; Globotruncana cf. ventricosa; Globotruncana dupeublei; Globotruncana duwi; Globotruncana falsostuarti; Globotruncana insignis; Globotruncana linneiana; Globotruncana mariei; Globotruncana orientalis; Globotruncana rosetta; Globotruncana rugosa; Globotruncana tricarinata; Globotruncana trinidadensis; Globotruncana ventricosa; Globotruncanella citae; Globotruncanella havanensis; Globotruncanella petaloidea; Globotruncanita angulata; Globotruncanita conica; Globotruncanita pettersi; Globotruncanita stuarti; Globotruncanita stuartiformis; Gublerina acuta; Gublerina cuvillieri; Gublerina robusta; Guembelitria cretacea; Hedbergella holmdelensis; Hedbergella monmouthensis; Hedbergella sliteri; Heterohelix cf. rajagopalani; Heterohelix globocarinata; Heterohelix globosa; Heterohelix navarroensis; Heterohelix planata; Heterohelix punctulata; Heterohelix rajagopalani; Heterohelix semicostata; Heterohelix striata; Joides Resolution; Laeviheterohelix dentata; Laeviheterohelix glabrans; Laeviheterohelix pulchra; Leg122; Ocean Drilling Program; ODP; Planoglobulina acervulinoides; Planoglobulina carseyae; Planoglobulina riograndensis; Pseudoguembelina costulata; Pseudoguembelina excolata; Pseudoguembelina palpebra; Pseudotextularia deformis; Pseudotextularia elegans; Pseudotextularia intermedia; Pseudotextularia nuttalli; Racemiguembelina fructicosa; Rugoglobigerina hexacamerata; Rugoglobigerina macrocephala; Rugoglobigerina milamensis; Rugoglobigerina pennyi; Rugoglobigerina rugosa; Rugoglobigerina scotti; Rugotruncana subcircumnodifer; Rugotruncana subpennyi; Sample code/label; South Indian Ridge, South Indian Ocean Planktonic foraminiferal diversity, equitability and biostratigraphic analysis of samples from Ocean Drilling Program (ODP) Leg 122, Hole 762C show that in general, cool water conditions prevailed during the latest Campanian–Maastrichtian in the eastern Indian Ocean. This is indicated by planktonic foraminiferal assemblages characterized by low species diversity and equitability with abundant rugoglobigerinids and heterohelicids. Archaeoglobigerinids, globigerinelloids, hedbergellids, and long-ranging double-keeled globotruncanids are also present in varying abundance but single-keeled forms occur rarely and sporadically. Identification of the stage and zonal boundaries for the studied geologic interval have been achieved through biostratigraphic analyses of closely spaced samples. Three planktonic foraminiferal biozones were identified, namely; in stratigraphic order, the Heterohelix rajagopalani, Contusotruncana contusa and Abathomphalus mayaroensis Zones. In Hole 762C, a Transitional Realm with Austral influences is defined for the latest Campanian to Maastrichtian, as shown by the high relative abundance of fauna characteristic of Transitional and Austral Realms. Austral endemic species such as Archaeoglobigerina australis Huber and Hedbergella sliteri Huber were found in the samples studied but Globigerinelloides impensus Sliter andA rchaeoglobigerina mateola Huber are conspicuously absent. From the latest Campanian to middle Maastrichtian, cooler parts of the Transitional Realm prevailed. A slight warming trend is assumed towards the end of the middle Maastrichtian because the faunas contain more species indicative of warm water conditions. The late Maastrichtian also appears to have been warmer than the latest Campanian-middle Maastrichtian. This conclusion is based on the high diversity and equitability values and recognition of some thermophilic taxa. A Tethyan influence is inferred for the latest Maastrichtian on the basis of an increase of planktonic foraminiferal species diversity and occurrences of several keeled taxa. |
| title | Distribution of foraminiferal fauna from ODP Hole 122-762C (Table 1) |
| topic | 122-762C; Abathomphalus intermedius; Abathomphalus mayaroensis; Archaeoglobigerina australis; Archaeoglobigerina blowi; Contusotruncana cf. fornicata; Contusotruncana cf. walfischensis; Contusotruncana contusa; Contusotruncana fornicata; Contusotruncana plummerae; Contusotruncana walfischensis; Counting >63 µm fraction; DEPTH, sediment/rock; DRILL; Drilling/drill rig; DSDP/ODP/IODP sample designation; Foraminifera; Foraminifera, benthic; Foraminifera, planktic; Foraminifera, planktic preservation; Globigerinelloides caseyi; Globigerinelloides multispinatus; Globigerinelloides prairiehillensis; Globigerinelloides subcarinatus; Globigerinelloides ultramicrus; Globotruncana aegyptiaca; Globotruncana arca; Globotruncana bulloides; Globotruncana cf. arca; Globotruncana cf. bulloides; Globotruncana cf. ventricosa; Globotruncana dupeublei; Globotruncana duwi; Globotruncana falsostuarti; Globotruncana insignis; Globotruncana linneiana; Globotruncana mariei; Globotruncana orientalis; Globotruncana rosetta; Globotruncana rugosa; Globotruncana tricarinata; Globotruncana trinidadensis; Globotruncana ventricosa; Globotruncanella citae; Globotruncanella havanensis; Globotruncanella petaloidea; Globotruncanita angulata; Globotruncanita conica; Globotruncanita pettersi; Globotruncanita stuarti; Globotruncanita stuartiformis; Gublerina acuta; Gublerina cuvillieri; Gublerina robusta; Guembelitria cretacea; Hedbergella holmdelensis; Hedbergella monmouthensis; Hedbergella sliteri; Heterohelix cf. rajagopalani; Heterohelix globocarinata; Heterohelix globosa; Heterohelix navarroensis; Heterohelix planata; Heterohelix punctulata; Heterohelix rajagopalani; Heterohelix semicostata; Heterohelix striata; Joides Resolution; Laeviheterohelix dentata; Laeviheterohelix glabrans; Laeviheterohelix pulchra; Leg122; Ocean Drilling Program; ODP; Planoglobulina acervulinoides; Planoglobulina carseyae; Planoglobulina riograndensis; Pseudoguembelina costulata; Pseudoguembelina excolata; Pseudoguembelina palpebra; Pseudotextularia deformis; Pseudotextularia elegans; Pseudotextularia intermedia; Pseudotextularia nuttalli; Racemiguembelina fructicosa; Rugoglobigerina hexacamerata; Rugoglobigerina macrocephala; Rugoglobigerina milamensis; Rugoglobigerina pennyi; Rugoglobigerina rugosa; Rugoglobigerina scotti; Rugotruncana subcircumnodifer; Rugotruncana subpennyi; Sample code/label; South Indian Ridge, South Indian Ocean |
| url | https://doi.org/10.1594/PANGAEA.755668 |