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The South Atlantic Transect (SAT) is a multidisciplinary scientific ocean drilling experiment designed to investigate the evolution of the ocean crust and overlying sediments across the western flank of the Mid-Atlantic Ridge. This project comprises four International Ocean Discovery Program expeditions: fully staffed Expeditions 390 and 393 (April-August 2022) built on engineering preparations during Expeditions 390C and 395E (October-December 2020 and April-June 2021, respectively) that took place without science parties during the height of the Coronavirus Disease 2019 (COVID-19) pandemic. Through operations along a crustal flow line at ~31°S, the SAT recovered complete sedimentary sections and the upper ~40-340 m of the underlying ocean crust formed at a slow-to intermediate-spreading rate at the Mid-Atlantic Ridge over the past ~61 My. The sediments along this transect were originally spot cored more than 50 y ago during Deep Sea Drilling Project Leg 3 (December 1968-January 1969) to help verify the theories of seafloor spreading and plate tectonics. The SAT expeditions targeted six primary sites on 7, 15, 31, 49, and 61 Ma ocean crust that fill critical gaps in our sampling of intact in situ ocean crust with regard to crustal age, spreading rate, and sediment thickness. Drilling these sites was required to investigate the history, duration, and intensity of the low-temperature hydrothermal interactions between the aging ocean crust and the evolving South Atlantic Ocean. This knowledge will improve the quantification of past hydrothermal contributions to global biogeochemical cycles and help develop a predictive understanding of the impacts of variable hydrothermal processes and exchanges. Samples from the transect of the previously unexplored sediment- and basalt-hosted deep biosphere beneath the South Atlantic Gyre are essential to refine global biomass estimates and examine microbial ecosystems' responses to variable conditions in a low-energy gyre and aging ocean crust. The transect, located near World Ocean Circulation Experiment Line A10, provides records of carbonate chemistry and deepwater mass properties across the western South Atlantic through key Cenozoic intervals of elevated atmospheric CO2 and rapid climate change. Reconstruction of the history of the deep western boundary current and deepwater formation in the Atlantic basins will yield crucial data to test hypotheses regarding the role of evolving thermohaline circulation patterns in climate change and the effects of tectonic gateways and climate on ocean acidification. During engineering Expeditions 390C and 395E (5 October-5 December 2020 and 6 April-6 June 2021, respectively), a single hole was cored through the sediment cover and into the uppermost rocks of the ocean crust with the advanced piston corer and extended core barrel systems at five of the six primary proposed SAT sites. Reentry systems with casing were then installed either into basement or within 10 m of basement at each of those five sites. Expedition 390 (7 April-7 June 2022) conducted operations at three of the SAT sites, recovering 700 m of core (77% recovery) over 30.3 days of on-site operations. Sediment coring, basement coring, and wireline logging were conducted at two sites on ~61 Ma crust (Sites U1556 and U1557), and sediment coring was completed at the 7 Ma Site U1559. During Expedition 390, more than 1.2 km of sediments was characterized, including 793 m of core collected during Expeditions 390C and 395E at Sites U1556, U1557, and U1559 as well as Expedition 395E Site U1561, which was cored on thinly (<50 m) sedimented ~61 Ma crust. The uppermost ~342 and ~120 m of ~61 Ma ocean crust was cored at Sites U1556 and U1557, respectively. Geophysical wireline logging was achieved at both sites, but the basement hole at Site U1556 was not preserved as a legacy hole because of subsidence of the reentry cone below the seafloor. At Site U1557, the drill bit was deposited on the seafloor prior to downhole logging, leaving Hole U1557D available for future deepening and establishing a legacy borehole for basement hydrothermal and microbiological experiments. Expedition 393 (7 June-7 August 2022) operated at four sites, drilling in 12 holes to complete this initial phase of the SAT. Complete sedimentary sections were collected at Sites U1558, U1583, and U1560 on 49, 31, and 15 Ma crust, respectively, and together with 257.7 m of sediments cored during earlier operations, more than 600 m of sediments was characterized. The uppermost ocean crust was drilled at Sites U1558, U1560, and U1583 with good penetration (~130 to ~204 meters subbasement); however, at the youngest ~7 Ma Site U1559, only ~43 m of basement penetration was achieved in this initial attempt. Geophysical wireline logs were achieved at Sites U1583 and U1560 only. Expeditions 390 and 393 established legacy sites available for future deepening and downhole basement hydrothermal and microbiological experiments at Sites U1557, U1560, and U1559 on 61, 15, and 7 Ma crust, respectively. Highlights of the SAT expeditions include (1) recovering abundant altered glass, hydrothermal veins, complex breccias, and a wide range of alteration halos in the volcanic sequences of the uppermost ocean crust formed at 7-61 Ma, indicating low-temperature hydrothermal processes and exchanges between seawater and basalts across the western flank of the southern Mid-Atlantic Ridge for millions to tens of millions of years; (2) documenting extended redox gradients from both the seafloor and the sediment/basement interface that indicate significant subsurface fluid flow and may support a diversity of microorganisms and metabolisms; and (3) recovering an almost complete stratigraphic record of the Cenozoic (including the Paleocene/Eocene Thermal Maximum and other key climate events) composed of nannofossil oozes with varying amounts of clay indicating the shoaling and deepening of the calcite compensation depth. [ABSTRACT FROM AUTHOR]

It is interesting to reveal how the limestone at Jeneponto was developed, the age, depositional environment, and stratigraphy position in the Tonasa Formation. The distribution of lithology is quite extensive in the form of spots and are only found along the southwest of the southern arm of Sulawesi. These phenomena show that there were similarities in the paleoceanographic condition in the past as in Barru area. Accordingly, limestone could also develop in this area. This research was conducted in the Karama area where the Tonasa limestone was well exposed, so that data collection using the measuring section method could be carried out. A total of 15 samples were prepared by the smear slide method and then identified calcareous nannofossils were under a polarizing microscope at 1000 x magnification. We want to focus on describing nannofossil at each layer, determining the age, and finally composing the biostratigraphic zonation of the Karama traverse. Nannofossil investigation results from the bottom to the top of section found nannofossil assemblages are Braarudosphaera sp., Cyclocargolithus abisectus, Dictyococcites antarcticus, Reticulofenestra sp., Ericsonia sp., Pontosphaera sp., Coccolithus pelagicus, Coccolithus eopelagicus, Discoaster deflandrei, Sphenolithus conicus, Sphenolithus moriformis, Sphenolithus delphix, Sphenolithus compactus, Sphenolithus predistentus, Zygrhablithus bijugatus. [ABSTRACT FROM AUTHOR]

The Istria Basin, part of Western Black Sea (WBS) represents a major tectonic unit of the Romanian Black Sea shelf, with prolific hydrocarbon bearing structures. A significant amount of exploration and development wells were drilled on this basin’s northern edge. Core and cuttings data from 12 boreholes provide important details on this basin and the WBS stratigraphy, especially for the two of the main hydrocarbons bearing deposits Upper Cretaceous and, respectively, Eocene, on which we have achieved an age interpretation, using calcareous nannofossil and foraminiferal assemblages. In this paper, we focus on the Upper Cretaceous comprised of Cenomanian, Turonian, Coniacian-Santonian, Campanian and Maastrichtian stages and on the Eocene ones, containing i.e., Ypresian, Lutetian and Bartonian stages. Our interpretation confirms the presence of three major unconformities. The oldest one is placed at the end of the Cretaceous, with a time gap of almost 10 My, which is estimated based on the ranges of the overlying Eocene planktonic foraminifera and calcareous nannofossils assemblages. The Paleocene series has not been not encountered in the studied wells. The second unconformity is intra-Eocene in age, referring to the upper part of the Lower Eocene (the upper part of Ypresian) is absent in several wells, especially in the southern part of our study area. The newest and most important unconformity marks a regional event at the beginning of Oligocene, well known in the literature as “Base Oligocene”, a regional marker for the WBS. In the Upper Cretaceous deposits, the presence and high diversity of planktonic foraminifera and calcareous nannofossils indicates that the water column was not deeper than ~200m and implicitly, it was an open marine environment. The Eocene microfossil assemblages also indicate a shallow marine environment, which may offer an indication of occasional subaerial exposure of the shelf area; this setting was the main factor in determining the occurrence of the Upper Cretaceous and Eocene first two unconformities. The origin of the third unconformity is miscellaneous, as Oligocene deposits are deep-water type. [ABSTRACT FROM AUTHOR]

The main purpose of this paper is to provide new geological information and interpretation of the well data from the Istria Basin, Western Black Sea. Therefore, we present a reconsideration of the microfaunas (mainly foraminifers) and calcareous nannofossils described from several wells drilled on the Lebada East structure belonging to the Istria Basin, by using core reports. Thus, we have been able to compile integrated information regarding the lithology and biostratigraphy of the wells. We have focused on the stratigraphy of the Upper Cretaceous deposits, placed in between the uppermost Lower Cretaceous (i.e., the Albian) sediments and the Eocene ones. Among the investigated wells, we present in this paper one well situated in the Lebada East structure. The drilled sediments are argillaceous sandstones and sandy-argillaceous limestones Cenomanian, followed by Santonian deposits, showing a similar lithology as above-described. Fossiliferous calcareous sandstones were deposited in the Campanian-lower Maastrichtian. The uppermost Cretaceous, i.e., the upper part of the Maastrichtian is composed of micritic limestones. The Upper Cretaceous stages have been distinguished by using planktonic foraminiferal biozonation. Hence, the Cenomanian was pointed out based on the presence of an assemblage with Thalmanninella appenninica, T. brotzeni and Rotalipora cushmani, while the upper Santonian depositional interval contain the planktonic foraminifers Dicarinella concavata and Globotruncana mariei, as significant biostratigraphic species. The Campanian-lower Maastrichtian depositional interval was pointed out by the presence in the calcareous nannofossil assemblage of the taxa Uniplanarius trifidus and Ceratolithoides aculeus. The Upper Cretaceous ends with a thick upper Maastrichtian succession enclosing significant foraminifers and calcareous nannofossils species. [ABSTRACT FROM AUTHOR]

The calcareous nannoplankton represents a group of major components of the oceanic phytoplankton, situated at the base of the trophic chain. The evolution pattern of these organisms is relevant in the past geological record and nowadays, for several research fields, such as: marine biology, marine geology, biogeochemistry, micropaleontology, biostratigraphy as well as paleogeographic and paleoclimatic reconstructions, including the paleoenvironmental ones. Taking into account that the calcareous nannoplankton species (namely calcareous nannofossils for the extinct taxa) already occur at the end of the Triassic, based on the fluctuation pattern in abundance and diversity, past climate and environmental changes may be revealed for approximately the last 205 million years. As the Black Sea basin experienced significant sea-level fluctuations and paleoenvironmental changes during its geological record, and especially within the Pleistocene-Holocene interval, the calcareous nannoplankton is employed for deciphering the aforementioned changes. Several investigations, including those presented herein, took place in the Black Sea based on this group of organisms both in the deeper parts of the basin and in the shallow ones (i.e., the continental shelf), revealing significant fluctuations of the extinct and extant assemblages. [ABSTRACT FROM AUTHOR]

This paper presents the results of micropaleontological research of foraminiferal fauna and calcareous nannofossils research of the Upper-Eocene sediments in the Delchevo and Strumica basins on the territory of the Serbian-Macedonian massif in the Republic of Macedonia, which are very important in solving the stratigraphy of the sediments. The studied micropalaeontological material was obtained from 31 samples coming from the upper flysh unit of 2 outcrop sections belonging to sedimentary basins: Delchevo and Strumica basin in the Serbian-Macedonian massif. The biostratigraphic significance of the foraminiferal fauna in the Upper-Eocene sediments is followed by stratigraphic distribution of 21 species of benthic and planktonic foraminiferal fauna, belonging to 18 genera and 15 families. The results of biostratigraphic nannofossil research revealed that the samples contain well preserved specimens of 17 species. Systematic classification of the foraminiferal fauna was done after Loeblich and Tappan (1988). [ABSTRACT FROM AUTHOR]

The article discusses the study done on the calcareous nannofossils from the type section for the formation of Rabisha sediments in North Western Bulgaria to determine its age. Topics discussed include absence of reliably determinable Gartnerago theta and Prediscosphaera cretacea, revealing that the sediments belong to Upper Albian–Lower Cenomanian, and moderate rate of average state of preservation of the observed nannofossil assemblages is moderate.