Distribution of benthic and planktic foraminifera in surface sediments of the Indian and Pakistan continental margin, Arabian Sea

• Main Author: Zobel, B
• Format: Dataset
• Language: English
• Published: PANGAEA 1973
• Subjects: Arabian Sea; BC; Bottom grab (Petterson); Box corer; BP; Eastern Arabian Sea; GC; GIK01201; Grab; Gravity corer; Gravity corer (Kiel type); IIOE - International Indian Ocean Expedition; KL; M1; M1_182; M1_183; M1_185; M1_186; M1_187; M1_188; M1_189; M1_190; M1_193; M1_194; M1_195; M1_196; M1_197; M1_198; M1_199; M1_200; M1_205; M1_206; M1_207; M1_208; M1_209; M1_210; M1_212; M1_213; M1_218; M1_219; M1_220; M1_222; M1_224; M1_226; M1_227; M1_229; M1_230; M1_233; M1_234; Indian; Planktonic foraminifera
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.548416; https://doi.org/10.1594/PANGAEA.548416

During the Indian Ocean Expedition of the German research vessel "Meteor" and the following cruise with the Pakistani fishing vessel "Machhera" in February and March 1965, sediments were sampled from the shelf, continental slope and the Arabian Basin off Pakistan and India. The biostratigraphic studies are based on sedimentary material from 24 sediment cores up to 480 cm long and 100 grab samples. The faunal residues of the > 160 µ fraction (chiefly foraminifera and pteropods) were determined and counted in order to get an idea of the climatic conditions during the Late Quaternary of this region. Biostratigraphic correlations of these Late Quaternary deposits are only possible if the thanatocoenosis of the surface sediments are well known. The analysis of the benthonic foraminiferal populations resulted in the definition of several foraminiferal facies. The following sequence of forarniniferal facies, named after their most characteristic members, can be distinguished from the shelf to the deep-sea: 1. Ammonia-Florilus facies 2. Ammonia-Cancris facies; 3. Cassidulina-Cibicides facies; 4. Uvigerina-Cassidulina facies 5. Buliminacea facies 6. deepwater facies, partly with Bulimina aculeata or with Nonionidae. On the upper continental slope there is a zone extremely poor in benthonic foraminifera. In this water depth the oxygen minimum layer (0.05-0.02 ml/l) of the water column reaches the slope. Almost no connection can be observed between the living and the dead foraminiferal population of the same sample. The regional distribution of the planktonic foraminifera from plankton tows as well as from the surface sediments shows marked differences in the species composition of faunas from different regions within the area of investigation. That depends on oceanographic conditions such as upwelling, dissolution of carbonate at great depths etc. Based on the results of faunal analysis of samples from the recent sea-floor, a biostratigraphic subdivision of the sediments in the cores was established. The ...