Benthic Foraminifera Research Articles

Strontium Isotopic, Ostracod fauna, and Paleoenvironmental Features of the Late Miocene Sequence in Mut/Dağpazarı Region (Southern Turkey)

The primary focus of this study was the Dağpazarı village in the Mut region of Mersin, southern Turkey. In this research area, two stratigraphic sections were meticulously measured. The study conducted a comprehensive examination of the Middle-Late Miocene period in the Dağpazarı, Ballı, and Mut Formations by analyzing the ostracod fauna and utilizing strontium isotope chemostratigraphic dating. This research determined that the upper levels of the Mut/Köselerli formations, specifically from the Burdigalian to Serravallian, signify the commencement of the Miocene succession in the study area.The Dağpazarı Formation, characterized by abundant silty-clay, Ostrea fossils, and lignite layers, is deposited unconformably just above these levels.This formation contains the following ostracod taxa; Bairdia subdeltoidea, C. glypta, Cytheridea acuminata acuminata, Acanthocythereis hystrix, Krithe monosteracensis, Neomonoceratina mouliana, Hemicyprideis sp., Cistacythereis caelatura, Cyherella terguemi, T. prava, K. langhiana, A. ulicznyi, Pokornyella deformis minor, Loxoconcha alata, Tenedocythere salebrosa. Furthermore, the planktonic foraminifera species are; O. universa, Globigerinoides trilobus, Glb. ruber, Orbulina bilobata, Glb. sacculifer, O. suturalis, and the formation includes abundant bryozoa, echinoid spines, gastropods such as Terebralia at distinct levels, and fish otolith. The formation, dating from the late Serravallian to the early Tortonian, exhibits the shallow reef characteristics that continued to develop in the late Miocene.The formation consists of dark green, bulbous weathered claystone, Bairdia subdeltoidea and Ostrea which are reduced in size at the levels that pass into hard clayey sandstone, abundant benthic foraminifera with abundant echinoid spines. The formation consists of benthic foraminifera, hard clayey sandstone, and weathered dark green claystone, which contains numerous echinoid spines.Ostrea and Bairdia subdeltoidea are also present. The upper section of the analyzed succession concludes with silty, compact, clayey limestone layers and light-colored limestone bands. The Tırtar Ballı Formation, which conformably overlays the Dağpazarı Formation, signifies the culmination of a relatively recent reef formation during the Tortonian period.Ostracod species such as Aurila pigadiana, Thalmannia hodgii, Buntonia sublatissima dertonensis, Bairdia subdeltoidea, Aurila sp. Bassiouni have been defined. The limestones also contain abundant benthic foraminifera and echinoid spines. The 87Sr/86Sr ratio analyzed from the carbonate sample obtained from the Dağpazarı formation is 0.708920. Based on these isotope data, the age of the Dağpazarı formation was calculated to be 8.7 million years (Ma).

Biostratigraphy of Shiranish Formation from Selected Wells, Central of Iraq

The Quantitative high-resolution planktonic foraminiferal analysis of the subsurface section in three selected wells in the Ajeel Oil Field (Aj-8, Aj-12, and Aj-15) in Tikrit Governorate, Central Iraq has revealed that Shiranish Formation deposited in Late Campanian- Latest Maastrichtian age. This formation consists mainly of marly and marly limestone yielding diverse planktonic foraminiferal assemblages and calcareous benthic foraminifera, with a total of 46 species that belong to 23 genera, Three zones and four subzones, which cover the Late Campanian to the Latest Maastrichtian, were identified based on the recorded planktonic foraminifera and their ranges. They are as follows:1. Globotruncana aegyptiaca Zone that dated to be Late Campanian 2. Gansserina gansseri Zone that refers to Early Maastrichtian 3. Abathomphalus mayaroensis Zone that indicates Late Maastrichtian, in this section, the Abathomphalus mayaroensis Zone is divided into four subzones, namely in that order from bottom to top: Racemiguembelina fructicosa (Early Late Maastrichtian), Pseudoguembelina hariaensis (Middle-Late Maastrichtian), P. palpebra ( Late Late Maastrichtian), and Plummerita hantkeninoides (latest Maastrichtian).

Millennial-scale changes in the environment, ice conditions, and deep-water ventilation at the Detroit–Tenji Seamounts, Northwest Pacific, over the last 43 kyr

The Western Subarctic Gyre (WSG) in the North Pacific represents the termination of the Atlantic Meridional Overturning Circulation (AMOC). It has been strongly influenced by periodic glaciations of adjacent landmasses, orbital- and millennial-scale variability of its environment, and ventilation, which, to date, have been poorly studied. In this study, we investigated sediment core LV76-21 recovered from the Detroit Seamount using several productivity and lithological proxies, δ18O records of planktic and benthic foraminifera (δ18Opf and δ18Obf), AMS 14C data. We also used the published results from three well-dated cores from the Detroit and Tenji Seamounts. Comparison of the δ18Opf and δ18Obf records allowed us to establish iceberg discharge events 1 and 1’ at 39–36.8 and 42–40 ka, respectively, in the WSG over the last 43 kyr. This was accompanied by considerable lightning of δ18Opf relative to the coeval δ18Obf values. The lithological results have also shown variable sea-ice influence on the regional environment during Marine Isotope Stage 3 and particularly 2, with sea ice extensions at 28.5–25.5 ka and 17.6–16.6 ka, and its significant loss since the Bølling–Allerød warming. We used high resolution δ18Obf records from studied cores as a subtle proxy of contribution of North Atlantic Deep Water (NADW) to Lower Circumpolar Deep Water (LCDW), which originating from around Antarctica and have slightly different δ18Obf values, in order to reconstruction of its spatial variability in the context of regional deep-water ventilation. The contribution of NADW to LCDW in the ventilation of the western flank of Detroit Seamount significantly increased during the interglacial and long-lasting Dansgaard–Oeschger interstadials, which was synchronous with the AMOC intensification. Over the last 43 kyr, the deep water of its eastern flank has been constantly ventilated by the LCDW with low contribution of NADW.

Preliminary report on the benthic foraminifera in the seas surrounding the Tokara Islands, southwest Japan

Preliminary report on the benthic foraminifera in the seas surrounding the Tokara Islands, southwest Japan

Oligocene biostratigraphy, depositional patterns, and stable isotope values in the eastern Zagros basin: Novel insight into the signature of regional and global events

Biostratigraphy, depositional environment, sequence stratigraphy, and paleoclimate iterpretation of the Asmari carbonate reservoir are the subject of the current study. Two, earlier uninvestigated stratigraphic sections are studied and correlated over the eastern Zagros basin. The vertical distribution of foraminifera (benthic and planktic) reveals that the Asmari Formation deposited during the Rupelian-Chattian. Three shallow benthic foraminifera biozones are established, namely the Globigerina-Turborotalia cerroazulensis-Hantkenina Assemblage Zone, the Nummulites vascus-Nummulites fichteli Assemblage Zone, and the Archaias asmaricus- Archaias hensoni-Miogypsinoides complanatus Assemblage Zone. Ten microfacies types associated with the inner, middle and outer ramp of a carbonate platform are identified. Three depositional sequences are recognized in the eastern Zagros basin. The oldest sequence is Rupelian in age, and two others are of Rupelian-Chattian and Chattian in age. Two maximum flooding surfaces occur in the eastern Zagros basin. The isotope startigraphical data show that the more positive values of the δ18O and δ13C coincide with the maximum flooding surfaces, while these values show depletion over the sequence boundaries. The exception is observed at the upper boundary of the succession where the hypersalinity conditions affected the trend. The stable isotope values obtained from bulk samples enable to identify the Oligocene glacial events such as Oi2 and, Oi2a (Rupelian) and Oi2b (Chattian). The examination of the grain associations of the MF3 and MF5 prove these cooling events. We suggest the middle ramp microfacies and MFS2 of Sq.2 as signatures for tracing these cooling events throughout the eastern Zagros basin.

ON THE AGE AND CONDITIONS OF THE FORMATION OF THE POLYANYTSKA SUITE ACCORDING TO THE FORAMINIFERA STUDY RESULTS (LOWER MIOCENE, BORYSLAV-POKUTTYA NAPPE, UKRAINIAN CARPATHIANS)

Neogene deposits of the Polyanytska Suite were exposed by the South Boryslav-1 well within the eastern block of the South Boryslav structure of the Boryslav oil and gas condensate field of the Outer Carpathians. The studied sediments of the Polyanytska Suite belong to the complex zone of planktonic foraminifers Globigerina pseudoedita with a characteristic association: Globigerina pseudoedita, Globoquadrina dehiscens, Dentoglobigerina langhiana, Trilobatus trilobus, Tenuitella brevispira, Tenuitella denseconnexa, Globorotalia tetracamerata, Globigerinella evoluta, Globigerinella obesa, Chiloguembelina gracillima. The Globigerina pseudoedita zone of planktonic foraminifera correlates with the zonal interval of nannoplankton NN2-NN3 of the Central Paratethys, which covers the upper part Eggerian, Eggenburgian, and the lowest part Ottnangian of the Central Paratethys and is compared with the upper Aquitan – the lower part of the Burdigal of the lower Miocene of the Neogene of the International Chronostratigraphic Scale. The sediments of the Polyanytska Suite were formed in a normally saline sea basin, with depths from the middle to the inner shelf. The medium shelf conditions (intervals 1812–1805 m; 1684–1645 m and 1546–1485 m in the the South Boryslav-1 well) are indicated by a relatively high percentage content and morphology of the shells of planktonic foraminifera, the taxonomic composition of calcareous benthic foraminifera. The presence of plankton indicates normal water salinity. Analysis of foraminifera in the interval 1395–1365 m indicates the depths of the inner shelf. The identified redeposited foraminifera of the Paleocene-Lower Oligocene testify to the erosion and demolition of clastic material from the uplifted part of the Carpathians.

Benthic Foraminifera as Proxies of Paleoenvironmental Changes in the Sant’Elia-Foxi Canyon (Gulf of Cagliari, Italy, Western Tyrrhenian Sea)

Marine coastal areas are highly dynamic and fragile environments characterised by a complex interplay of biological, physical, and chemical factors. These areas are also affected by anthropogenic activities with the discharge of organic and inorganic contaminants that alters the quality of the environment. In this work, the effects of anthropogenic activities (i.e., urban and industrial development) on benthic foraminifera have been investigated along the A2TM core collected from the Sant’Elia-Foxi Canyon (Gulf of Cagliari, Sardinia—western Tyrrhenian Sea). The Gulf of Cagliari has experienced intense urbanisation since the beginning of the twentieth century with the establishment of petrochemical complexes and harbour activities. The A2TM core, dating from 1907 to 2013, was analysed with an integrated approach that includes grain size, organic matter, and benthic foraminifera characterisation compared with geochemical characterisation. The variations in the composition of the benthic foraminiferal assemblages and the Margalef diversity index are related to the altered environmental conditions that reflect the historical development of the area and to the land-based activities surrounding the Gulf of Cagliari. The statistical analysis identifies two main intervals (i.e., the years 1907–1986 and 1986–2013) that are typified by different benthic foraminiferal assemblages and diversity values. Accordingly, the increases in organic matter content and both organic and inorganic contaminants are well mirrored by a major drop in foraminiferal diversity after 1973 and a major foraminiferal turnover after 1989. The composition of the benthic foraminiferal assemblages in the uppermost part of the core (i.e., 1989–2013) might suggest a lowering of the oxygen availability at the seafloor. These changes might be related to the increase in organic matter and the silty fraction in the same interval likely triggered by damming on land and wetland reclamation.

Late Cretaceous (Cenomanian-Turonian) temperature evolution and biotic response in the Adriatic Carbonate Platform region of Friuli, northeast Italy

Climate modelling and palaeotemperature reconstructions derived from several proxies (TEX86, δ18O) suggest that the Late Cretaceous was one of the warmest intervals in Earth history. The greenhouse climate reached its acme near the Cenomanian-Turonian boundary (CTB) interval with sea surface temperatures over 35 °C in low and mid- palaeolatitudes, coinciding with the highest sea level stands of the Phanerozoic. Following this warming phase, a general cooling trend punctuated by short-term hot snaps characterized the rest of the Cretaceous. Palaeotemperature and palaeoenvironmental changes are well documented in deep-water carbonate deposits based on variations in geochemical proxies and distribution patterns of macro- and microfauna. However, such climatic and environmental fluctuations severely impacted carbonate platforms, sedimentary environments that are particularly sensitive to external perturbations. Palaeontological data show major changes within the main carbonate platform producers (rudists and benthic foraminifera) during the early Late Cretaceous. Both groups experienced major taxonomic turnovers at the CTB, followed by a further re-radiation in the middle/late Turonian. The lack of detailed palaeoclimatic reconstructions in shallow water carbonate succession hampers the possibility to investigate a possible causal relationship between temperature changes and faunal evolution. In this paper, we report integrated geochemical, sedimentological, and palaeontological data from the Adriatic Carbonate Platform (Friuli, north-east Italy). Benthic foraminifera biostratigraphy and isotope stratigraphy (δ13C and 87Sr/86Sr) were used to precisely constrain the stratigraphy of the late Cenomanian-middle Turonian interval. δ18O analysis on both well-preserved rudist shells and bulk rock samples enabled the construction of high-resolution palaeotemperature curves. The resulting temperature trends are comparable with those from the deep-water record across the late Cenomanian-Turonian interval. The warmest phase was in the Early Turonian with sea surface palaeotemperatures as high as 41–45 °C recorded in rudist shells. Data show temperature fluctuation from the late Cenomanian to the Early Turonian with a magnitude >7 °C. Benthic foraminifera and rudist evolution responded to these palaeotemperature fluctuations, and their decline in the late Cenomanian and full recovery in the Turonian suggest a strong link with temperature changes.

Paleoenvironmental changes during the Late Pleistocene in Buenos Aires province (Argentina), using foraminifera fauna as proxy data

This paper describes the lithological and micropaleontological characteristics of a new record corresponding to the last interglacial for Buenos Aires province. Foraminifera were analyzed from an artificial outcrop 4 m thick (36°34′0.97″ S and 57°22′54.43″ W), from the quarry situated in the town of General Conesa, Buenos Aires province at an approximate elevation of 4 m a.s.l. Benthic foraminifera fauna was constituted by a predominance of calcareous forms represented mostly by the species Buccella peruviana and Ammonia parkinsoniana. The micropaleontological and lithological characteristics of all the sedimentary units involved in this locality suggest deposits associated with a transition from a low-energy shallow intertidal or subtidal zone to a higher-energy beach or supratidal environment. Although, the topographic height does not enable conclusive assignment of the age of this coastal deposit (>79.500 kyr), the environmental conditions could be correlated with the penultimate transgressive event that occurred at the beginning of the Late Pleistocene (MIS 5), which would have occurred in a shallow environment with changes in the marine influence. These findings provide new information that contributes to better understanding of the paleoenvironmental evolution of this region where two marine transgressions and two wind deposits have been recognized.

Benthic foraminifera as bioindicators of marine pollution: A bibliometric approach to unravel trends, patterns and perspectives

Benthic foraminifera, single-celled marine organisms, are known for their wide distribution, high abundance and species diversity, test (i.e., shell) preservation in the sedimentary (e.g., historical) record, and sensitivity to environmental changes. Because of these characteristics, they have been widely used as bioindicators in environmental monitoring and, more recently, as Biological Quality Elements (BQEs) in the Ecological Quality Status (EcoQS) evaluation. The global scientific literature on benthic foraminifera as bioindicators was gathered from the Scopus database (overall 966 papers from 1973 to 2022) and explored with scientometric software. The outcomes highlight that the investigation of benthic foraminiferal response to pollutants started over 50 years ago. Indeed, not only the number of published documents has recently peaked (i.e., 2021 and 2022) but there has been also a growth in the percentages of papers falling within the Decision Sciences category that deals with the application of foraminiferal indices for the EcoQS assessment.

Impact of seawater sulfate concentration on sulfur concentration and isotopic composition in calcite of two cultured benthic foraminifera

Abstract. Marine sediments can be used to reconstruct the evolution of seawater [SO42-] and δ34S over time, two key parameters that contribute to refine our understanding of the sulfur cycle and thus of Earth's redox state. δ34S evolution can be measured from carbonates, barites and sulfate evaporites. [SO42-] variations can be reconstructed using fluid inclusions in halites, a method that only allows a low-resolution record. Reconstruction of the past sulfur cycle could be improved if carbonates allowed the tracking of both seawater δ34S and [SO42-] variations in a sole, continuous sedimentary repository. However, most primary carbonates formed in the ocean are biogenic, and organisms tend to overprint the geochemical signatures of their carbonates through a combination of processes often collectively referred to as vital effects. Hence, calibrations are needed to allow seawater δ34S and [SO42-] reconstructions based on biogenic carbonates. Because foraminifera are important marine calcifiers, we opted to focus on calcite synthesized by individuals of rosalinid benthic foraminifera cultured in the laboratory under controlled conditions, with varying seawater [SO42-] (ranging from 0 to 180 mM). Our experimental design allowed us to obtain foraminiferal asexual reproduction over several generations. We measured bulk carbonate-associated sulfate (CAS) content and sulfur isotopic composition (δ34SCAS) on samples of tens to hundreds of specimens from a selection of culture media, where [SO42-] varied from 5 to 60 mM. Increasing or decreasing [SO42-] with respect to modern-day seawater concentration (28 mM) impacted foraminiferal population size dynamics and the total amount of bioprecipitated carbonate. Foraminiferal CAS concentration increased proportionally with [SO42-] concentration from 5 mM up to 28 mM and then showed a plateau from 28 to 60 mM. The existence of a threshold at 28 mM is interpreted as the result of a control on the precipitation fluid chemistry that foraminifera exert on the carbonate precipitation loci. However, at high seawater sulfate concentrations (> 40 mM) the formation of sulfate complexes with other cations may partially contribute to the non-linearity of the CAS concentration in foraminiferal tests at high increases in [SO42-]. Yet, despite the significant effect of seawater [SO42-] on foraminiferal reproduction and on CAS incorporation, the isotopic fractionation between CAS and seawater remains stable through varying seawater [SO42-]. Altogether, these results illustrate that CAS in biogenic calcite could constitute a good proxy for both seawater [SO42-] and δ34S and suggests that sulfate likely plays a role in foraminiferal biomineralization and biological activity.

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The biodiversity of benthic foraminifera around the coral communities and the concentration of heavy elements (e.g., Mn, Fe, Cr, Cu, Ni, Pb, Zn, Cd, and Co) in Miskan Island and Al-Khiran coastline of Kuwait are used as an ecological indicator for the environmental and anthropogenic stresses occurred from February 2018 to February 2019. The study resulted in identifying 19 families, 6 orders, 29 genera, and 94 species. Using R-mode cluster analysis results in four assemblages and using Q-mode principal component analysis (PCA) distinguished three groups depending on the deep. The three main assemblages refer to different depths, Group A from 20 cm to 1 m depth; Group B from 1.5 to 2 m depth, Group C from 6 to 8 m depth. Al-Khiran coastline is characterized by anoxic conditions, confirmed by the existence of pyrite. Additionally, high water turbidity because of anthropogenic effects. The low number of benthic foraminifera on Miskan Island is due to the dissolution and calcification of foraminifera shells. The Island characterized by freshwater runoff from Iraq meets saltwater in the gulf, affecting the salinity. The turbidity is caused by sediment runoff and eutrophication. Both sites were considered relatively unpolluted compared with the nearest Iranian coast. However, the relatively high potentially toxic elements in some locations are due to the semi-restricted geographic characteristic and high anthropogenic activity. There is no clear abnormality in the identified species showing normal aperture, coiling, shape, and size.

Azoic sediments and benthic foraminifera: Environmental quality in a subtropical coastal lagoon in the gulf of California

Marine transitional environments play an important role in human sustainability. Around these ecosystems, coastal lagoons are subject to high anthropogenic pressure from population growth. The increased demand for goods and services is associated with the elevated discharge of untreated and treated wastewater into lagoon systems. The absence of benthic organisms in lagoon environments has been linked to extreme natural conditions and severe anthropogenic impact at both spatial and temporal scales. However, the mechanisms that lead to the presence of azoic sediments in lagoon environments have yet to be studied. This study aimed to determine the vertical variability of textural groups, geochemistry, and benthic foraminiferal fauna to understand how natural and anthropogenic components generate a vertical sediment sequence with low or absent benthic foraminifera in a subtropical coastal lagoon in the southwestern end of the Gulf of California. A 41 cm-long sediment core was collected from La Paz Lagoon at a 1-m depth. The core was sectioned every centimeter, and sediment subsamples were dried and homogenized for grain size, calcium carbonate, elemental and isotopic carbon and nitrogen analyses, and benthic foraminifera quantification. Muds with fine sands towards the core's base characterized the sedimentary sequence. Organic carbon and total nitrogen increased from the base (1.4% and 0.06%, respectively) to the core-top (CT, 3.0% and 0.14%, respectively), significant from the 27 cm interval. Calcium carbonate content was very low (<0.8%). The relationship of δ13C vs. C:N ratio indicated that sedimentary organic carbon was derived from the marine and sewage source mixture. The δ15N of organic matter increased by 3.7‰, starting from the 27 cm interval towards the CT. The nitrogen sewage input source was relatively more significant than nitrogen fixation. The few individuals (<18 ind. in 10 g) and genera (Ammonia and Elphidium), as well as the absence of foraminifera in 19 of 41 intervals in the core, indicated that environmental conditions were unfavorable, even for colonization of environmentally stress-tolerant genera. The frequency of azoic sediments was higher from the 25 cm interval to the CT vs. from the base to the 25 cm interval. Moreover, the AEI revealed severe to moderate hypoxia in the study area. The limited presence of benthic foraminifera and calcium carbonate preservation corroborated that the quality of the lagoon's environment has deteriorated along with population growth, which requires strategic programs to sustain this transitional ecosystem.

Subenvironments of Jeribe Formation (M. Miocene) deduced from microfacies study, Zurbatiya Area, South-East of Iraq

The current study of Jeribe Formation (Middle Miocene) at Zurbatiya area, South-East of Iraq. It is, structurally, located in the Low Folded Zone. The topic depends mainly on the study of microfacies under a microscope. One surface section in the Zurbatiya area is represented in the Wadi Al-Numur section. It is composed basically of dolomitic limestone. Petrography provides a diversity of fauna, such as benthic foraminifera Miliolid, Borelis melo curdica, and Rotalia in addition to Ostracoda, Algae, Coral, and Mollusks. Borelis melo curdica is considered an index fossil for the Jeribe Formation. The non-skeletal grains like peloids, ooids intraclasts, and extraclasts. The Jeribe Formation was affected by many diagenetic processes like neomorphisim, dissolution, cementation, dolomitization, compaction, and silicification. Sedimentary microfacies are classified into three main microfacies, which are dolomudstone, dolowackestone, and dolopackstone. These microfacies were divided into many submicrofacies, which are peloidal dolomudstone, ostrocods dolomudstone, rotaliids dolowackstone, miliolid dolowackstone, bioclasts dolowackstone, green and red algae dolowackstone, red algae dolopackestone, and coral dolopackestone. The evidence from petrography and microfacies analysis supports that the Jeribe Formation was deposited in the back reef, reef, and lagoon environments.

Biostratigraphy and Microfacies of the Mauddud Formation (Late Albian – Early Cenomanian) in Musaiyib Well No.1, Central Iraq

Upper Albian and Lower Cenomanian biostratigraphy and microfacies types of the Mauddud Formation from Musaiyib well No.1, Central Iraq are described and examined, which consists of thick to medium bedded limestone, marly limestone rich in argillaceous material, green shale, and dolomitic limestone beds. Thirty-six species from twenty-two genera of benthic foraminifera in addition to calcareous algae, coral, bivalves, gastropods, rudist fragments, brachiopods, bryozoan, and echinoid fragments are recognized from the Mauddud Formation of the studied well. On the basis of the recognized benthic foraminifera three biozones were determined: Mesorbitolina texana - Orbitolina qatarica Concurrent Range zone- Orbitolina sefini-Total R. Zone and Orbtolina concava Total R. Zone. Both suggest the Late Albian – Early Cenomanian age. The results of this study are compared with the work of others inside and outside Iraq. Based on the petrographical analyses, four major microfacies (Mudstone, wackestone, wackestone to packstone, and packstone), and nine sub-microfacies were identified. The Mauddud Formation was formed in a marine environment that was composed of the following three sub-environments: the inner ramp and the middle to the outer ramp.

Single-celled bioturbators: benthic foraminifera mediate oxygen penetration and prokaryotic diversity in intertidal sediment

Abstract. Bioturbation processes influence particulate (sediment reworking) and dissolved (bioirrigation) fluxes at the sediment–water interface. Recent works showed that benthic foraminifera largely contribute to sediment reworking in intertidal mudflats, yet their role in bioirrigation processes remains unknown. In a laboratory experiment, we showed that foraminifera motion behaviour increased the oxygen penetration depth and decreased the total organic content. Their activity in the top 5 mm of the sediment also affected prokaryotic community structure. Indeed, in bioturbated sediment, bacterial richness was reduced, and sulfate-reducing taxa abundance in deeper layers was also reduced, probably inhibited by the larger oxygen penetration depth. Since foraminifera can modify both particulate and dissolved fluxes, their role as bioturbators can no longer be neglected. They are further able to mediate the prokaryotic community, suggesting that they play a major role in the benthic ecosystem functioning and may be the first described single-celled eukaryotic ecosystem engineers.

Shallow-water carbonate facies herald the onset of the Palaeocene-Eocene Thermal Maximum (Hazara basin, Northern Pakistan)

We investigate the Palaeocene succession of the Hazara Basin (Northern Pakistan) to better understand the impact of climate change on marine carbonate-producing organisms. These shallow-water carbonates, deposited during the Late Palaeocene, before the onset of the Palaeocene-Eocene Thermal Maximum, were studied using a quantitative approach to highlight changes in the skeletal assemblage. We recognise a decrease in the abundance of colonial corals and green calcareous algae and an increase in larger benthic foraminifera and red calcareous algae from the early Thanetian to the late Thanetian. Increasing temperatures may represent a plausible cause for the decline of the more sensitive colonial corals in favor of the more tolerant larger benthic foraminifera. A similar pattern is observed in most successions deposited along the margins of the Neotethys Ocean, suggesting a connection with the Late Palaeocene environmental changes that heralded the PETM hyperthermal event. Our stratigraphic analysis of the Hazara Basin strata suggests that the biotic turnovers occurred during the Palaeocene – Eocene transition started already before the onset of the Palaeocene Eocene Thermal Maximum as recorded by the geochemical proxies.

Assessing atmospheric and oceanic teleconnections between the eastern and western Mediterranean over the past 8000 years

Holocene climate records from the Mediterranean are marked by pervasive millennial to centennial-scale climate variability. Here, we investigate East-West Mediterranean atmospheric and oceanic teleconnections by computing phase-relationships between oxygen isotope (δ18O) records generated on Soreq (East) and Chorchia (West) spelaeothems, as well as between δ18O and carbon isotope (δ13C) records from planktonic and benthic foraminifera from core PS009PC (East, Levantin Basin), ODP Site 963D (Central, Sicily Strait), and core KESC9-14 (West, Ligurian Basin). These marine sites are all located at intermediate water depths (560–460 m depth). Hence, the benthic foraminiferal δ18O records reflect mainly the intermediate ocean temperature/δ18O of the water mass, and the benthic δ13C is a proxy for the intensity of water flowing at the studied depth called Levantine Intermediate Water (LIW). For both western and eastern cores, the planktonic stable isotopic records reflect the climate-induced activity of the nearby river system. We find broadly in-phase relationships between the spelaeothem δ18O records and between the planktonic δ18O and δ13C records at most multi-centennial and millennial periodicities. This is indicative of closely linked (hydro-) climatic conditions in Southern Europe, the Levant, and North Africa over the last 8000 years. Conversely, at intermediate water depths, we find a distinct out-of-phase relationship between the East/Central and West Mediterranean benthic δ18O and δ13C records at 1000–2000 years periodicities. We interpret this see-saw pattern as indicative of a persistent regional influence of LIW on oceanographic conditions in the intermediate depths of the eastern basin. Conversely, we suggest a strong influence of the modified Atlantic Ocean inflow (MAW) in the intermediate water formation in the Western Mediterranean (‘Winter Intermediate Water’; WIW). This WIW overprints, at least partially, the LIW signal that reaches the western Mediterranean causing the out-of-phase relationship between the east and the west oceanographic signals at intermediate depths.

TAXONOMIC AND BIOSTRATIGRAPHIC REMARKS ON TORINOSUELLA MAYNC, 1959 AND BALKHANIA MAMONTOVA, 1966, LARGER BENTHIC FORAMINIFERA FROM THE LOWER CRETACEOUS OF IRAN (SANGESTAN, TIRGAN FORMATIONS)

The monospecific genera Torinosuella Maync [type-species T. peneropliformis (Yabe &amp; Hanzawa)] and Balkhania Mamontova (type-species B. balkhanica Mamontova) have been reported from the Lower Cretaceous of Iran, respectively the ‘Carbonate Member’ of the Sangestan Formation (Central Iran) and the Tirgan Formation (NE Iran). The literature review reveals a range of late? Tithonian–early Barremian for Torinosuella and late Barremian–early Aptian for Balkhania. In a recent publication dealing with the ‘Taft’ Formation (Central Iran) and the Tirgan Formation (northeastern Iran), both taxa have been lumped together and described as two morphotypes of B. balkhanica based essentially on size differences. This mixing was associated with incorrect phylogenetic, taxonomic, biostratigraphic (e.g., First Appearance Datum) and palaeoecological conclusions that are herein addressed and corrected. Without clarification about the spatial and temporal distribution of individual taxa, the usefulness of larger benthic foraminifera for biostratigraphy, palaeoecology and palaeobiogeography would be distinctly reduced.

Late Cretaceous erosion and chemical weathering record in the offshore Cape Basin: Source-to-sink system from Hf[sbnd]Nd isotopes and clay mineralogy

Source-to-sink research has often used sediment fluxes as a fundamental parameter when seeking to understand the perturbations caused by tectonics or climate. This parameter is often interpreted only in terms of erosion rates, dismissing the component exerted by chemical weathering. In this study, we characterize sediments from the Deep Surface Drilling Program core 361 (DSDP 361) located in the Cape basin to show the evolution of both, physical erosion and silicate chemical weathering, during the late Cretaceous (100.5–66 Ma) in the source-to-sink system consisting of the South African plateau and the Cape Basin. Transmission Electron Microscopy (TEM) images and trace element analyses indicate that detrital clays predominate within the site and thus reflect variations in surface continental processes. Clay mineralogy shows a predominance of detrital smectite (60–98%) throughout the section. However, an increase in primary clay minerals, in particular illite (20%), indicates a relative enhancement in physical erosion, while an increase in palygorskite (10%) indicates regional climate aridification during the Campanian–Danian interval (ca. 77–62 Ma). Concomitant to this enhancement, we observe both, more radiogenic Hf isotopic compositions and less radiogenic Nd isotopic compositions in the clay fractions (< 2 μm). These variations can be respectively associated to an increase in silicate chemical weathering and the incorporation of unradiogenic material, likely related to the orogenic belts present on the western-south margin of Southern Africa. The regional aridification and the global climate cooling trend observed on δ18O benthic foraminifera records do not appear as suitable mechanisms for the increase in physical erosion and silicate chemical weathering observed. Our results, together with the reported increase in sedimentation rates and the reported tectonic uplift between 80 and 70 Ma, suggest that it is tectonic activity and not climate the main driver in the enhancement of denudation processes. Furthermore, our data suggests that such uplift episode could have impacted the regional climate by causing a rain-shadow effect, with an inland aridification suggested by the increase in palygorskite proportions. The increase in silicate chemical weathering suggested by our new dataset begins in the Campanian (ca. 77 Ma), later than the onset of the global climatic cooling trend that occurs from the Turonian onward. If enhanced weathering of the South African Plateau may not have triggered the recorded climatic cooling, it may still have contributed to maintain cooler conditions in the Campanian-Danian interval.