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Biostratigraphy, microfacies, and reservoir quality of the Oligocene Qom Formation (Kharzan Section, north-west of Ardestan, central Iran)

Arani Asma Aftabi, Ashouri Ali Reza, Daneshian Jahanbakhsh, Ghaderi Abbas, Wood David A.

Geological Quarterly

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2023

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Vol. 67, No. 3

art. no. 23

EN

The central Iran Basin is a region with unique environmental characteristics in which the Late Paleogene–Early Neogene benthic foraminifera display distinctive distributions and abundances that can assist in identifying the intervals with the best reservoir potential. Lipidocyclinid and miogypsinid zonal marker taxa in this region can be correlated with those in the SBZ23 region (European Basin), indicating an Oligocene (Chattian) age. With sedimentation of continental strata of the Upper Red Formation following the marine succession of the Qom Formation, it seems that the last Tethyan marine transgression in the Ardestan region in central Iran occurred in the Oligocene, and the Tethyan seaway was permanently closed during the Miocene. Seven carbonate microfacies and marl or silty marl facies were identified in the study area based on field investigations, textural analysis and faunal assemblages. These microfacies were deposited on an open-shelf carbonate platform in lagoonal, patch-reef, and open-marine belts that effectively define both inner and middle-shelf environments. Micritization, cementation, mechanical and chemical compaction, dissolution and fracturing are the most important diagenetic processes controlling reservoir quality in the Qom Formation. The investigation of these processes in the facies of the Qom formation in the Kharzan section revealed that intervals associated with shallow lagoonal depositional environments display better reservoir quality than other formation intervals, due to dissolution and fracturing.

2

Ichnology of Upper Cretaceous–lower Palaeogene deep-sea deposits in the Haymana Basin of Central Anatolia

Demircan Huriye, Görmüş Muhittin

Annales Societatis Geologorum Poloniae

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2020

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Vol. 90, No. 4

463--493

EN

Upper Cretaceous to lower Palaeogene carbonate and siliciclastic deposits that crop out widely in the Haymana and Polatlı districts (Ankara Province) of the Haymana Basin (Central Anatolia) are rich in larger benthic foraminifera, various macrofossils and ichnofossils. The ichnofossils of the Haymana and Yeşilyurt formations were studied at five localities. The Upper Cretaceous siliciclastics of the Haymana Formation contain moderately diverse trace fossils, belonging to the deep-sea Nereites ichnofacies. The Paleocene siliciclastic and carbonate deposits of the Yeşilyurt Formation comprise similar trace fossils, which do not show significant changes in comparison to the Haymana Formation. This indicates that the K-Pg boundary extinction event did not affect the ichnofauna with any longer consequences. The Upper Cretaceous coarser, siliciclastic deposits of the Haymana and Beyobası formations are rich in shallow-marine, larger benthic foraminifera, including species of Orbitoides, Omphalocyclus, Siderolites, Hellenocyclina, and Loftusia, whereas fine siliciclastic deposits contain abundant planktonic, open-marine foraminifera, such as Globotruncana and Heterohelix. Palaeogene siliciclastic to carbonate deposits of the Kartal, Yeşilyurt and Çaldağ formations are rich in the larger, benthic foraminifera Nummulites, Discocyclina, Assilina and Alveolina. The larger foraminifers have been redeposited from nearby, shallow-marine parts of the basin.

3

Dasycladalean green algae and associated foraminifers in Middle Triassic (Lower and Middle Muschelkalk) carbonates of the south-eastern Germanic Basin (Upper Silesia, Poland)

Bucur Ioan I., Matysik Michał

Annales Societatis Geologorum Poloniae

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2020

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Vol. 90, No. 4

391--407

EN

Middle Triassic dasycladalean algae occur in limestones and dolstones of the Diplopora Beds in Upper Silesia, a region representing the southern part of the Germanic Basin. The dasycladales assemblage of this area was studied by Kotański at the end of the last century, mostly from dolomitized and weathered material. The relatively well-preserved specimens the authors found in thin sections from undolomitized strata allowed the description and revised taxonomical assignment of the algae. The identified microflora includes: Diplopora annulatissima Pia, 1920, Diplopora annulata (Schafhäutl, 1853), Salpingoporella cf. krupkaensis Kotański, 2013, Physoporella prisca Pia, 1912, Physoporella cf. pauciforata (Gümbel, 1872), Holosporella? sp. 1, and Holosporella? sp. 2. Diplopora annulatissima and Favoporella annulata Sokač, 1986 are regarded here as two different species. Oligoporella elegans Assmann ex Pia, 1931, extensively illustrated and described by Kotański (2013), is considered a junior synonym of Oligoporella prisca Pia, 1912, and transferred to the genus Physoporella emended by Grgasovic, 1995. Also, some of the dasycladalean algae (Salpingoporella cf. krupkaensis, Holosporella? sp. 1, and Holosporella? sp. 2) described here could represent new species, but more well-preserved material is necessary. The algae are accompanied by foraminiferal microfauna, which collectively indicate a late Anisian (Illyrian) age of the strata studied.

4

Seasonal variations, environmental parameters, and standing crop assessment of benthic foraminifera in eastern Bahrain, Arabian Gulf

Arslan M., Kaminski M. A., Tawabini B. S., Ilyas M., Babalola L. O., Frontalini F.

Geological Quarterly

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2016

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Vol. 60, No. 1

26--37

EN

Living benthic foraminifera in a relatively unpolluted site offshore Bahrain in the Arabian Gulf, were studied to determine the seasonal variability of their populations, as well as environmental parameters that may affect their distribution. The maximum foraminiferal density was observed during winter with the assemblages primarily dominated by rotaliids and secondarily by miliolids. The high population is attributed to an increased number of juveniles. A relationship between sediment grain size and the foraminiferal density reveals that juveniles were most abundant on coarse-grained sandy substrate and less abundant on fine-grained substrates. In spring, the foraminiferal density decreased, and the lowest values were observed during summer. The population increased again in autumn with highest juvenile/adult ratios. Moreover, results of relative abundance and species consistency show that Ammonia and Glabratellina are consistent from the shallowest to the deepest station, whereas miliolids occurred only at deeper stations. The numbers of peneroplidae and Elphidium also increased along the depth transect. Environmental characterization reveals that although the site is subject to eutrophication caused by nitrates and sulfates, pollution caused by hydrocarbons and heavy metals is not significant. The assessment of 63 heavy metals showed that none of the metals had concentrations that exceed internationally accepted norms [the devised level of Effect Range-Low], but with high concentration of strontium. The lack of a significant environmental effect of heavy metals is confirmed by the Foraminiferal Abnormality Index of <2%. Likewise, no hydrocarbon contamination was detected in the water or sediment samples. We conclude that the site in Bahrain is not yet adversely affected by human development, and therefore can provide baseline information for future comparison and assessment of foraminiferal assemblages in contaminated zones of the Arabian Gulf.

5

Does the recent pool of benthic foraminiferal tests in fjordic surface sediments reflect interannual environmental changes? The resolution limit of the foraminiferal record

Łącka M., Zajączkowski M.

Annales Societatis Geologorum Poloniae

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2016

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Vol. 86, No. 1

59--71

EN

Benthic foraminifera tests (living + dead) and conductivity, temperature and depth (CTD) records in Hornsund Fjord (SW Spitsbergen) were studied over five non-consecutive summer seasons during 2002–2011. The data indicated significant changes in the abundance of benthic foraminifera, species composition and the variability of hydrological and micro-environmental conditions in this fjord. The increased inflow of Atlantic Water (AW) resulted in higher foraminiferal biodiversity and a greater number of rare species; however, many of these were fragile and were thus poorly preserved in the sediment. Cold years significantly reduced species richness in the fjord centre, while more stable hydrological conditions with a predominance of opportunistic foraminifera were noted at the fjord head. Elphidium excavatum f. clavata and Cassidulina reniforme exhibited sensitivity to salinity changes and food supply. The dynamic foraminiferal response to hydrological changes led to the conclusion that the annual foraminiferal flux, compounded by the poor preservation of fragile individuals, significantly changed the spatial and interannual composition of the foraminiferal tests remaining in the sediment. Furthermore, only mature individuals are representative of yearlong or multi-year fjord conditions, since the juveniles that bloom during their maximum growth periods in spring can die out under poor summer and winter conditions. The findings of this study indicated that the upper 8 cm of the sediment in the intense depositional systems of the Svalbard fjords provide good representation of recently departed benthic foraminifera, because of their mobility in surface sediments and further sediment compaction. Hence, the corresponding 10- to 15-year resolution in palaeoceanographic investigations seems to be the most reliable.

6

Stratygrafia wapieni tytonu dolnego-aptu dolnego skałki Niedźwiedź w allochtonie wierchowym polskich Tatr Zachodnich

Borowska U.

Przegląd Geologiczny

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2015

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Vol. 63, nr 3

164–-171

EN

Benthic foraminifera, tintinnids and calcareous dinocysts provide new important biostratigraphic data on the age of the Raptawicka Turnia Limestone Formation and Wysoka Turnia Limestone Formation of the NiedŸwiedŸ crag geological section in the Polish Western Tatra Mts. Foraminiferal assemblages of shallow- water limestones from the NiedŸwiedŸ section contain some stratigraphically significant species, including Haghimashella arcuata (Haeusler), Protomarssonella kummi (Zedler), Uvigerinammina uvigeriniformis (Seibold & Seibold) and Textulariopsis jurassica (Guembel). Sporadic planktonic microfossils, such as the tintinnid Tintinnopsella carpathica (Murgeanu & Filipescu), calcareous dinocysts (Cadosina minuta Borza, Colomisphaera lucida Borza, C. tenuis (Nagy), C. varia Øechanek and Parastomiosphaera malmica (Borza), have also been identified. On the basis of these microfossil assemblages the lower and middle parts of the NiedŸwiedŸ section was dated as the Lower Tithonian–Barremian. Limestones of the Raptawicka Turnia Limestone Formation section represent peloidal, peloidal-oolitic and peloidal-oolitic-bioclastic facies. Limestones from the Wysoka Turnia Limestone Formation of the NiedŸwiedŸ section was dated as the Upper Barremian–Lower Aptian, based on a specific composition of foraminifera assemblages, that suggest an eroded carbonate platform as a source of Urgonian-type carbonate material. The boundary between the formations occurs within a poorly dated interval (Valanginian–Barremian).

7

Heavy metals contamination and distribution of benthic foraminifera from the Red Sea coastal area, Jeddah, Saudi Arabia

Youssef M.

Oceanologia

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2015

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No. 57 (3)

236--250

EN

The distribution of benthic foraminifera was studied in two stations in the coastal area, located around Jeddah, Red Sea coast, Saudi Arabia. Thirty-three species belonging to 15 genera, 14 families and three suborders were recorded in twenty samples. Some foraminiferal tests display abnormalities in their coiling, general shape of chambers and apertures. On the other hand, concentrations of Fe, Mn, Zn, Cu, Pb, Ni, Cr, and Cd were measured in the tests of the two most common living species of benthic foraminifera (Sorites marginalis and Peneroplis planatus). Significant spatial differences in the metal concentrations of benthic foraminifera were recorded at the two sites. Benthic foraminifera yielded significantly high concentrations of Fe, Mn, Pb and Cu, which may attribute to anthropogenic activities at the studied coastal areas. The anthropogenic activities have a considerable impact, besides other factors, in the abnormalities of foraminiferal test.

8

Deep water masses in the Iceland Basin during the Last Interglacial (MIS 5e): Evidence from benthic foraminiferal data

Lukashina N. P., Bashirova L. D.

Oceanologia

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2015

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No. 57 (2)

212--221

EN

The Last Interglacial period, marine isotope stage (MIS) 5e, is a potential analogue for the Holocene. In this study, we investigated a marine sediment core, AMK-4442, recovered from the northern part of the Iceland Basin. The multiproxy approach used in this study, which includes foraminiferal and lithological analyses, identifies the difference in intensity of deep circulation between MIS 5e and the Holocene. Our data indicate that during early MIS 5e, the Iceland-Scotland Overflow Water (ISOW) flux into the Iceland Basin was suppressed. We suggest that the less active North Atlantic Deep Water (NADW) formation at this time was related to the obstruction of warm surface water inflow into the Nordic Seas.

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Response of eastern Indian Ocean (ODP Site 762B) benthic foraminiferal assemblages to the closure of the Indonesian seaway

Rai A. K., Singh W. B.

Oceanologia

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2012

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No. 54 (3)

449-472

EN

Pliocene-Pleistocene deep sea benthic foraminifera from ODP Site 762B in the eastern Indian Ocean were examined to understand the tectonically/climatically induced palaeoceanographic changes. In addition to already published data on this site by Rai & Singh (2001), some more faunal parameters were considered in the present work. Characteristic benthic foraminiferal assemblages as well as more diverse fauna during the early Pliocene (before 3.5 Ma) reflected relatively oligotrophic and warm bottom water conditions. At the beginning of the late Pliocene (i.e. ~3 š 0.5 Ma) relative abundances of Uvigerina proboscidea, infaunal taxa and high productivity taxa increased, whereas faunal diversity showed a distinct decline, suggesting the development of pronounced upwelling resulting in higher surface water productivity. The strongly reduced inflow of warm and oligotrophic water masses as the South Equatorial Current (SEC) from the South Pacific to the eastern Indian Ocean due to the effective closure of the Indonesian seaway increased the surface water productivity. The closing of the Indonesian seaway during the late Pliocene was also responsible for the cessation of the warm, southward-flowing Leeuwin Current (LC) and the greater influence of the cold, deep and northward-flowing Western Australian Current (WAC) in the eastern Indian Ocean.

10

The Danian and Selandian calcareous benthic foraminiferal assemblages and biostratigraphy of Western Siberia

Podobina Vera

Geologos

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2011

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Vol. 17, No. 2

97--110

EN

Danian and Selandian successions in western Siberia are rich in calcareous benthic foraminifers. The assemblages with a constant systematic composition that have the widest lateral occurrence are distinguished as foraminiferal zones. The Brotzenella praeacuta Zone was established in the low-carbonate, clayey beds that form the transition from the Gankinskaya Suite to the Talitskaya Suite. These transitional beds are assigned to the Danian. The calcareous benthic foraminifers in this zone occur mainly together with agglutinated forms. The zone is traced along the areas of the largest subsidence of the Mesozoic-Cenozoic basin, principally in depressions. The transition from the Cretaceous to the Palaeogene is represented by a continuous succession, in which the Danian deposits escaped from erosion and were found to contain the B. praeacuta assemblage. In Danian rocks with a shallow-marine facies (near Beryozovo and in the Ust’-Tym depression, Fig. 1), the Bathysiphon nodosarieformis - Glomospira charoides assemblage occurs. It is dominated by primitive forms in addition to more advanced tests (mainly Late Maastrichtian relic species). The overlying Selandian (Middle Palaeocene) foraminiferal assemblages are assigned to the Talitskaya Suite. The Ammoscalaria friabilis assemblage is widely spread and is represented mainly by agglutinated quartz-siliceous forms. Beds with these species are attributed to the Ammoscalaria friabilis Zone, which can be correlated with beds in the East containing Cyclammina coksuvorovae. The Cibicidoides proprius assemblage is known from the lower and middle beds of the Talitskaya Suite in Transuralia, the Omsk Depression and more south-eastern areas; the species of this assemblage are characteristic of the Selandian.

11

Micropalaeontological analysis of olistoliths from the Wieliczka Salt Mine (Outer Carpathians, Poland)

Machaniec E., Zapałowicz-Bilan B.

Studia Geologica Polonica

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2005

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Vol. 124

273-284

EN

Upper Cretaceous variegated marls of a Węglówka-type facies are exposed in the form of olistoliths within the Zuber-type salt deposits at the higher exploitation level of the "Kunegunda" Drift in the Wieliczka Salt Mine. This is the southernmost zone of occurrence of redeposited blocks of the Carpathian flysch sediments within the Miocene salt deposits of the Carpathian Foredeep. The variegated marls contain considerably diversified assemblages consisting only of small benthic foraminifera, including both agglutinated and calcareous taxa. Basing on the ranges of the characteristic species the variegated marls in the "Kunegunda" drift are dated as Turonian-Campanian. Two zones of benthonic agglutinated foraminifera have been recognised: the Uvigerinammina jankoi and Goesella rugosa zones. The foraminiferal assemblage of the youngest segment of the Węglówka marls is dominated by calcareous benthonic taxa with Stensioeina gracilis Brotzen as the most numerous species. Its presence indicates a Campanian age of this part of the studied deposits.

12

Checklist and annotated bibliography of Recent Foraminiferida from the German Baltic Sea coast

Frenzel P., Tech T., Bartholdy J.

Studia Geologica Polonica

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2005

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Vol. 124

67-86

EN

There are 96 Recent foraminiferal species reported from the German sector of the Baltic Sea. All are benthic taxa. Most species are agglutinated forms, reflecting the brackish water conditions of the southern Baltic Sea. Decreasing diversity is visible following the salinity gradient along the coast from the west to the east. The associations of the deeper water below the halocline and of shallow water above are very different with higher diversity in the deeper water. A complete species list and annotated bibliography for Recent foraminiferal species from the brackish water of the German Baltic Sea coast are presented.

13

Benthic foraminiferal morphogroups and taphonomy of the Cieszyn beds (Tithonian-Neocomian, Polish Outer Carpathians)

Szydło A.

Studia Geologica Polonica

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2005

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Vol. 124

199-214

EN

Test gross morphology and taphonomy of calcareous benthic foraminifers from the Cieszyn beds were mainly controlled by depositional parameters, paleoecological conditions and paleogeographical settings. All of these control factors were influenced by a major tectonic event represented by the rifting of the Cieszyn Basin. In its earliest history it acted as a gulf adjacent to the Eastern European Platform. The Tithonian marls and marly shales known in Polish regional geology as the lower Cieszyn shales and Cieszyn limestones yielded highly diverse calcareous benthic foraminiferal assemblages which are dominated by shallow and deep infaunal morphogroups. A remarkably well-developed epifaunal component can be recognized as well. Shelf and peri-reefal foraminifera originally developed their life cycles under well-oxygenated conditions in the immediate proximity of the sea-bottom. The initiation of turbidite sedimentation lead to the removal and transportation of shelf foraminifers into deeper water environments (bathyal). Consequently, the tests of calcareous foraminifers are small, and poorly preserved, presenting dissolution traces, and abraded and corroded surfaces. The mixed and reworked microfauna were replaced by a more uniform one in the proximity of the Jurassic/Cretaceous boundary. Active omnivorous infauna survived not only the change of deposition system but also the deepening of the Cieszyn Basin during Early Cretaceous times. Periodically the supply of reworked and allochthonous calcareous benthic forms into the Cieszyn Basin took place during the Berriasian and Late Valanginian-Hauterivian times.

14

Benthic foraminiferal response to the Cenomanian-Turonian and Cretaceous-Paleogene boundary events

Peryt D.

Przegląd Geologiczny

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2004

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Vol. 52, nr 8/2

827-8

EN

The present paper summarizes previously published results of my studies on the Cenomanian-Turonian and Cretaceous-Paleogene changes in benthic foraminiferal assemblages. The recorded changes indicate that the rate and intensity of restructuring of benthic foraminiferal populations during the Cenomanian-Turonian Boundary Event (CTBE) and Cretaceous-Paleogene Boundary Event (KTBE) strongly depended on the duration and severity of environmental stress. A stepwise extinction within benthic foraminiferal assemblages, a bloom of infaunal and semi-infaunal morphotypes during the CTBE and a relatively long-lasting survival interval (the Whiteinella archaeocretacea chron) most likely reflect the decline in oxygenation level of the bottom waters at the end of the Rotalipora cushmani chron and persistence of these unfavourable conditions during the Whiteinella archaeocretacea chron. A catastrophic type of mass extinction within benthic foraminiferal assemblages, extinction or temporary emigration of most of infaunal morphogroups during the KPBE and a relatively short survival interval are interpreted to be the result of a sudden breakdown in food supply as the consequence of a sudden collapse in primary productivity, probably resulting from the impact of the K-P asteroid.

15

Otwornice bentosowe a granica kreda/paleogen (K/P) w profilu Ain Settara, Tunezja

Peryt D., Alegret L., Molina E.

Przegląd Geologiczny

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2003

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Vol. 51, nr 12

1069-1074

PL

Z odsłonięcia Ain Settara (północna Tunezja) zbadano ponad 12-metrowy profil osadów najwyższego mastrychtu (2,5 m) i dolnego paleogenu (9.6 m) reprezentujący następujące poziomy otwornicowe: Plummerita hantkeninoides, Guembelitria cretacea, Parvularugoglobigerina eugubina i Parasubbotina pseudobulloides . W osadach najwyższego mastrychtu zespoły otwornic bentosowych są zróżnicowane pod względem taksonomicznym z podobnym udziałem form infaunalnych i epifaunalnych. Dramatyczna zmiana w strukturze zespołów otwornic bentosowych jest równoczesna z tworzeniem się warstewki z anomaliami geochemicznymi, tj. w spągu poziomu Guembelitria cretacea, gdzie zróżnicowane i o niskiej dominacji zespoły otwornicowe zostają zastąpione przez zespoły zubożone pod względem taksonomicznym a zdominowane przez epifaunalne morfogrupy. W tym momencie 14 rodzajów zanika. Niektóre z nich wymierają, podczas gdy inne pojawiają się ponownie w dolnym danie jako taksony Łazarza. Naszym zdaniem gwałtowny spadek dopływu pokarmu będący skutkiem załamania produkcji pierwotnej i równoczesnej zmiany w składzie fitoplanktonu (z przewagi nanoplanktonu wapiennego na przewagę bruzdnic) mogły być bezpośrednią przyczyną restrukturyzacji zespołów otwornic bentosowych. Globalne załamanie produkcji pierwotnej było prawdopodobnie skutkiem impaktu asteroidu na półwyspie Jukatan.

EN

The outer shelf-upper bathyal section across the Cretaceous/Paleogene (K/P) boundary at Am Settara (Central Tunisia) has been studied for quantitative changes in benthic foraminiferal assemblages. The studied interval extends from 2.5 m below to 9.6 m above the Cretaceous/Paleogene (K/P) boundary and encompasses the uppermost Plummerita hantkeninoides, Guembelitria cretacea, Parvularugoglobigerina eugubina and Parasubbotina pseudobulloides planktonie foraminiferal zones. In the uppermost Maastrichtian benthic foraminiferal assemblages are highly diversified and composed of mixed epifaunal and infaunal morphogroups. The dramatic change in the structure of benthic foraminiferal assemblages corresponds to the layer with the impact evidence, i.e., at the base of the Guembelitria cretacea Zone where highly diversified, low-dominance Upper Maastrichtian assemblages with infaunal and epifaunal morphogroups were suddenly replaced by taxonomically impoverished assemblages, strongly dominated by epifaunal morphogroups. At this level several species with inferred infaunal mode of life disappeared. Some of them went extinct, whereas others reappeared in the Lower Danian as Lazarus taxa. We interpret that a sudden breakdown of the food supply as a consequence of a collapse in primary productivity and simultaneous changes in the phytoplankton composition (from calcareous nannoplankton to dinoflagellates) resulted in extinction or temporary emigration of most infaunal morphogroups. The sudden collapse of primary productivity probably resulted from the impact of the K/P asteroid.