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The Krishna Godavari Basin is located in the East Coast Indian Peninsula containing 5 to 7 km of Cretaceous through Cenozoic terrigenous clastic sediments. The Miocene-Pliocene section in the offshore is known as the Ravva Formation, a major argillaceous facies with sandstone beds from which oil and gas are being produced. In this sequence, some cutting samples studied from four offshore wells were found to be rich in agglutinated benthic foraminifera, while planktic foraminifera were absent at these levels. These samples were studied in much detail for agglutinated foraminifera. A total of fifty-nine agglutinated foraminiferal species belonging to thirty-five genera have been identified. Two new species, Alveolophragmium indicum Govindan n. sp and Liebusella krishna Govindan n. sp., are described. All these species are reported for the first time from this region. The agglutinated benthic foraminiferal taxa bear close resemblance to those of Miocene agglutinated foraminifera assemblages reported from South Trinidad, the Falcon Basin of Venezuela, and offshore West Africa. The present report of alveolar genera, Alveovalvulina, Alveovalvulinella and Guppyella, and compressed, inner partitioned alveolar genera Pavonitina and Spiropsammia, together with other genera having complex reticulate inner structure as Cyclammina, Reticulophragmium and Alveolophragmium in this region are of great importance for the evaluation of biostratigraphy, paleoecology, paleobiogeography and burial history. Paleoecological analysis reveals three agglutinated foraminiferal biofacies/groupings, which characterize beyond outer shelf through bathyal slope (500 to 1500m) depth regimes in an oxygen minimum deep water setting for the deposition of these turbidite/debris flow sediments.
A major marine transgression at the close of the Oligocene probably caused a moderately rich, more uniform distribution of deep water agglutinated species over this deep basin. Additional observations on the agglutinated benthic assemblage such as deformation of the tests, coloration of the tests and stratigraphic markers are also dealt with briefly.
Recent studies on the biostratigraphy and fauna of the Lower Ordovician successions of the Russian part of Baltoscandia have shown for the first time that agglutinated foraminifers are very numerous in the deposits of the lower part of the Latorp Russian Regional Stage in the vicinity of St. Petersburg, northwestern Russia. These forms were discovered in a classic section exposed on the left side of the Lava River canyon in the northern outskirts of the village of Vassilkovo. The lower part of the Latorp Regional Stage is represented in this section by unlithified sands and clays of the Lakity Member of the basal part of the Leetse Formation and corresponds to the upper part of the Hunneberg Regional Stage of Baltoscandia. The clay beds of the Lakity Member encompass the upper part of the Paroistodus proteus and lower part of the Prioniodus elegans conodont zones and correspond to the Tetragraptus phyllograptoides graptolite zone. Foraminifers from the Lakity Member were collected from strata belonging to both of the above mentioned conodont zones and are represented by monothalamous agglutinated foraminiferal tests of a new species of a new genus Lakites ordovicus n. gen., n. sp., new species of the genus Amphitremoida: A. asperella n. sp., A. laevis n. sp., A. longa n. sp., A. orbicularis n. sp., and A. rugosa n. sp. (family Hippocrepinellidae), a new genus and species Lavella cucumeriformis n. gen., n. sp. of the family Saccamminidae, and one specimen assigned to the genus Arenosiphon? of the family Hippocrepinidae. The finding of representatives of the genus Amphitremoida (emended herein), previously known only from the Middle Ordovician to the Lower Carboniferous (Tournaisian) permits the extension of the range of this genus down into the Lower Ordovician.
The Permian - Triassic boundary of the Çürük dağ section (Taurus, Antalya Nappes, Turkey) was sampled for ostracodes. 38 species belonging to 22 genera were discovered. This ostracode fauna is the first one described throughout the Permian -Triassic boundary outside of South China. Six species are new: Sargentina pamucakensis Crasquin-Soleau n. sp., Bairdia kemerensis Crasquin-Soleau n. sp., Bairdiacypris ottomanensis Crasquin-Soleau n. sp., Liuzhinia antalyaensis Crasquin-Soleau n. sp., Arqoviella tahtaliensis Crasquin-Soleau n. sp., Callicythere lysi Crasquin-Soleau n. sp.
The ostracodes at the base of the Kokarkuyu Formation (Induan) are the oldest Triassic forms ever discovered (Hindeodus parvus and Isarcicella isarcica staeschei zones). The Permian genus Revyia is recognized for the first time in Triassic and the Triassic genera Callicythere and Luizhinia for the first time in the Permian.
The fauna discovered here, in the very first levels of the Triassic, illustrate the turn-over between Paleozoic and Mesozoic forms.
This study reports twin and triplet forms of Recent benthic foraminifera from the eastern Aegean Sea. We discuss new insights into the causes of abnormal morphologies, including possible anthropogenic influences. The twin and triplet forms, their morphologies and environmental characteristics are described with a view to aiding interpretation of the Recent and ancient palaeoenvironmental record.
Micrite nodules are the only source of Radiolaria within the upper Tithonian to Aptian (Upper Jurassic-Lower Cretaceous) interval of Great Valley Supergroup (GVS), California Coast Ranges. Radiolaria recovered from GVS micrite nodules are either calcified or pyritized. This paper describes a method of extracting well preserved calcified radiolaria from micrites utilizing acetic acid. The same method resulted in the extraction of well preserved Upper Cretaceous planktonic foraminifera from indurated micrite within the Khoy ophiolitic complex of northwestern Iran; from micrite in the Green Horn Formation, Pueblo Colorado; from indurated chalk in the Austin Chalk, Dallas Texas, and from indurated micrite in Albian Duck Creek Formation of Texas. The preservation of extracted radiolaria and planktonic foraminifera from the indurated micrites and chalk is excellent and is often comparable to that found in most DSDP/ODP samples. Assumedly the clay content of the rock, and the chemical homogeneity of the calcified test are the principal reasons for differential solution of the acetic acid.
Two methods for retrieving foraminifera from strongly lithified carbonates (Amine-O and cold-disaggregation with acetic acid) were tested on the same sample of Oxfordian spongiolithic limestone (Prebetic Zone, SE Spain) and compared with thin section analysis. Differences between the methods concern: 1) weight of sieved residues after disaggregation; 2) foraminifera/gram ratio; 3) preservation features of the tests; 4) foraminiferal assemblage compositions. The results obtained allow us to conclude that accurate paleoecological and taxonomical analysis of indurated carbonates requires the combined use of thin sections and disaggegration treatment of the samples.