Danuta Peryt

The Cenomanian-Turonian Oceanic Anoxic Event in SE Poland

Stable isotopes (13C, 18O), CaCO3 contents, carbon content insoluble in HCl (Corg) and in the carbonates (Ccarb), and foraminifers have been investigated in the Cenomanian-Turonian boundary interval (uppermost Rotalipora cushmani Zone and lower Whiteinella archaeocretacea Zone) in SE Poland. The stage boundary is defined by the appearance of the coccolith species Quadrum gartneri Prins & Perch-Nielsen. The higher content of Corg in the uppermost Rotalipora cushmani Zone and lowermost Whiteinella archaeocretacea Zone, a δ 13C and δ 18O stable isotope anomaly in the uppermost Cenomanian, and substantial changes in the foraminiferal assemblages have been recorded. A major carbon stable isotope excursion with a shift of up to +2.0‰ δ 13C (PDB) is located a short distance above the Rotalipora cushmani-Whiteinella archaeocretacea boundary within marly limestones. The peak value of δ 13C corresponds to the minimum P/B ratio, and minima in the diversity and abundance of foraminiferal assemblages. A late Cenomanian expanding mid-water oxygen minimum zone is thought to be responsible for changes in foraminiferal assemblages in the uppermost Rotalipora cushmani and lower Whiteinella archaeocretacea Zones.

Deep-water agglutinated foraminiferal changes and stable isotope profiles across the Cretaceous–Paleogene boundary in the Rotwandgraben section, Eastern Alps (Austria)

Abstract The studied interval extends from 2.5 m below to 1 m above the Cretaceous–Paleogene (K–P) boundary and encompasses the uppermost Abathomphalus mayaroensis , PO (subzones: POa — Guembelitria cretacea and POb — Globoconusa conusa ), Pα or Parvularugoglobigerina eugubina and lowermost P1 (subzone: P1a or Subbotina pseudobulloides ) planktonic foraminiferal zones. The agglutinated benthic foraminiferal assemblages of the uppermost Abathomphalus mayaroensis Zone are moderately diversified and composed of mixed epifaunal and infaunal morphogroups. In the lower part of the Guembelitria cretacea Subzone benthic foraminifers are extremely rare and represented only by a few epifaunal species; in the upper part of this subzone they are still not abundant but assemblages are again moderately diversified. In the Globoconusa conusa Subzone deep-water agglutinated foraminifers are abundant, highly diversified and represented by mixed epifaunal and infaunal morphogroups. Bulk rock stable isotope analysis shows a significant drop of both δ 13 C and δ 18 O values at the K–P boundary. It appears that a drastic decrease in abundance and diversity of deep-water agglutinated foraminifers as well as a change of the community structure from mixed epifaunal and infaunal to one dominated by epifaunal morphogroups are related to a reduction in marine primary productivity. The instantaneous environmental stress and the collapse of primary productivity, are compatible with a large bolide impact.

The Cenomanian/Turonian boundary event in Central Poland

Abstract Stable isotopes (13C, 18O), CaCO3 content, carbon content insoluble in HCl (Corg) and in the carbonates (Ccarb), and foraminifers have been investigated in the Cenomanian/Turonian boundary interval (Rotalipora cushmani Zone and lower Whiteinella archaeocretacea Zone) in southeast Central Poland. A higher content of Corg in the uppermost Rotalipora cushmani Zone and lowermost Whiteinella archaeocretacea Zone, a δ13C and δ18O stable isotope anomaly in the uppermost Cenomanian, and substantial changes in the foraminiferal assemblages have been recorded. A major carbon stable isotope excursion with a shift of up to +1.6‰ (PDB) recorded in the lower part of the Whiteinella archaeocretacea Zone within the marly limestone in the uppermost Cenomanian. A late Cenomanian expanding oxygen minimum zone is thought to be responsible for changes in foraminiferal assemblages.

Benthonic foraminiferal mass extinction and survival assemblages from the Cenomanian-Turonian Boundary Event in the Menoyo Section, northern Spain

Abstract Foraminiferal response to the Cenomanian-Turonian Boundary Event was studied from a 50 m thick section in Menoyo, northern Spain, representing the uppermost Rotalipora cushmani and Whiteinella archaeocretacea Zones. Taxonomic and stratigraphic studies on benthonic foraminiferal assemblages indicate that the studied section represents mass extinction and survival intervals, with the mass extinction boundary in the lowermost part of the Whiteinella archaeocretacea Zone. Stepped extinction within benthonic foraminifers was observed in the uppermost Rotalipora cushmani Zone. In the late phase of mass extinction several species became extinct (e.g. Gavelinella intermedia-cenomanica-baltica group, Tritaxia pyramidata (Reuss)), some others temporarily disappeared; Lazarus taxa (e.g. Tritaxia tricarinata (Reuss), nodosariids) and progenitor (e.g. Globoratalites sp. 1) taxa appeared. Disaster (e.g. Praebulimina elata) species along with opportunistic taxa (e.g. Gyroidinoides praestans (Magniez-Jannin), Ammobaculites parvispira Ten Dam) colonized vacated ecospace in the middle part of the survival interval, i.e. in the topmost part of the Rotalipora cushmani Zone. Opportunistic taxa dominated assemblages in the Whiteinella archaeocretacea Zone, i.e. in the higher part of the survival interval. The recorded changes in benthonic foraminiferal assemblages most likely reflect the decline in oxygenation level of the bottom waters at the end of the Rotalipora cushmani Zone and the persistence of these unfavourable conditions in the Whiteinella archaeocretacea Zone.

The cretaceous/paleogene boundary and planktonic foraminifera in the flyschgosau (Eastern Alps, Austria)

The studied interval extends from 2.5 m below to 1 m above the Cretaceous/Paleogene (K/P) boundary and comprises the uppermost Maastrichtian marly limestone overlain by a boundary (rusty) layer—a dark yellow orange clay 5–10 mm thick, followed by a turbidite sequence of very fine sandstones and grey-brown marls. The following planktonic foraminiferal zones are distinguished: Abathompalus mayaroensis, PO (subzones: POa— Guembelitria cretacea and POb — Globoconusa conusa), Pa or Parvularugoglobigerina eugubina and P1 (subzone: P1a or Subbotina pseudobulloides). The distribution of iridium shows a relatively sharp rise to a maximum value of 7.176 ppb about 1.2 cm above the rusty layer, followed by a rapid drop to normal background levels. The Abathomphalus mayaroensis Zone exhibits a moderately diverse planktonic foraminiferal assemblage. The main extinction episode occurs within the rusty layer; only a few species survived. Survivors are small primitive forms. The first new Paleocene species evolved immediately after the major Cretaceous extinctions. Rapid extinction of planktonic foraminifers coincides with the iridium anomaly which suggests that, at this site, the source(s) of the iridium anomaly was (were) probably responsible for K/P extinctions.

The Cenomanian/Turonian boundary in Sakhalin, Far East Russia: ammonites, inoceramids, foraminifera, and radiolarians

Abstract The Cenomanian‐Turonian succession of faunal assemblages identified in Sakhalin has enabled the establishment of 10 ammonite, 7 inoceramid, 4 radiolarian, and 2 foraminiferal zones, which correlate relatively well with those recorded for the northeastern region of Russia (Kamchatka and Koryakia) and for Japan. The problems surrounding placement of the Cenomanian/Turonian boundary in Sakhalin and in adjacent areas are reviewed. Significant macrofaunal turnover and radiation have been identified across the (locally defined) Cenomanian/Turonian boundary, as well as in the middle Turonian for ammonites and in the upper Turonian for inoceramids. The first occurrences of the widely distributed Pacific ammonite Jimboiceras planulatiforme (Jimbo), the cosmopolitan ammonite Fagesia, and the inoceramid Mytiloides aff. labiatus (Schlötheim), define the base of the Turonian Stage. The succession of foraminiferal assemblages does not exhibit any major extinction at the Cenomanian/Turonian boundary; however, a temporary faunal restructuring occurred at that time. The radiolarian fauna appears to have survived this interval without marked taxonomic change; a diversity decrease took place later, near the middle/late Turonian boundary.

The late Cenomanian oceanic anoxic event in the western Anglo‐Paris basin and southeast Danish‐Polish trough: Survival strategies of and recolonisation by benthonic foraminifera

Prolonged dysaerobic conditions probably caused the extinctions recorded within many of the late Cenomanian marine benthonic foraminiferal community. The surviving low diversity assemblage contains morphotypic associations that may be recognised over a wide geographical area. Environmental pressure selected for low oxygen tolerant infaunal forms and others that could readily adapt to this mode of life. The recolonisation by the benthonic foraminifera was very slow, in the western Anglo‐Paris Basin and in the southeast Danish‐Polish Trough, in contrast to the planktonic foraminifera. This may be a result of several influences: low migration rates of benthonic foraminifera, appreciably deeper water, the persistance of oxygen‐poor water at depth and/or changes in substrate induced by the radically different Turonian carbonate facies.

Environmental changes in the declining Middle Miocene Badenian evaporite basin of the Ukrainian Carpathian Foredeep (Kudryntsi section)

Environmental changes in the declining Middle Miocene Badenian evaporite basin of the Ukrainian Carpathian Foredeep (Kudryntsi section) The Kudryntsi section in West Ukraine documents a major environmental change from hypersaline to marine conditions during the Middle Miocene. There are very few (or no) specimens of foraminifers in samples of the siliciclastic series (4 m thick, with limestone intercalations) which occurs above the gypsum (and below the transgressive deposits) in the southern part of quarry. The limestone intercalations are first sparitic and microsparitic, and then become pelletal. The pelletal depositional textures are interpreted as originated in restricted environments in contrast to mixed-fossil lithoclastic packstones/grainstones overlying the siliciclastic series. The diversity of fauna increases up section. Foraminifers, bivalves, ostracods and gastropods appear first and then, additionally, brachiopods, bryozoans, crinoids, and echinoids occur. Foraminiferal assemblages are dominated by elphidiids forming 70 to 90 % of the population. The most common species are Elphidium crispum (Linné) and E. macellum (Fichtel & Moll). The limestones show a wide range of δ13C values (from -1.6 ‰ to - 18.2 ‰) and δ18O values (from -0.2 ‰ to -9.4 ‰) indicating that the cementation and some recrystallization took place in meteoric-water-dominated fluid but the restriction-controlled trend can be recognized. The siliciclastic series was deposited in an evaporitic lagoon influenced by large inflows of continental waters carrying the siliciclastic and other detrital material from the older Badenian rocks as well as from their substrate. The Kudryntsi section documents a stepwise decrease in water salinity — from ca. 150-300 ‰ during the Badenian gypsum precipitation, through ca. 80-150 ‰ during deposition of the siliciclastic series to ca. 35 ‰ during sedimentation of the basal transgressive deposits. The basal deposits originated in shallow subtidal (0-20 m) environments of normal marine salinity (30-35 ‰) and temperate to warm waters (8-18 °C) as indicated by requirements of the E. crispum association in recent seas.

The Lower/Upper Maastrichtian boundary interval in the Lublin Syncline (SE Poland, Boreal realm): new insight into foraminiferal stratigraphy

A detailed micropaleontological study of the upper part of the Lower and Upper Maastrichtian strata of the Lublin Syncline (SE Poland) recorded several foraminiferal events and foraminiferal event stratigraphy turned out to be useful for interregional correlation. Main foraminiferal events recorded are: the temporary disappearance of Rugoglobigerina spp. coinciding with the last occurrence of Angulogavelinella gracilis; the reappearance of Globotruncana spp. after a longer absence in the area; the temporary disappear ance of Stensioeina spp. and the last occurrence of Gavelinella monterelensis, as well as a short-lived bloom of Globotruncanella petaloidea. The reappearance of Globotruncanidae in SE Poland slightly above the base of the Belemnitella junior Zone probably reflects a global sea level rise recognised in north-western Europe and eastern North America. The temporary disappearance of the genus Rugoglobigerina at the base of the Belemnitella junior Zone may be used as a good marker for the Lower/Upper Maastrichtian substage boundary in the Boreal Province.

Carbon and oxygen isotopic composition of the Middle Miocene Badenian gypsum-associated limestones of West Ukraine

The Middle Miocene Badenian basin of the Carpathian Foredeep is characterized by complex sedimentary and diagenetic carbonate-evaporite transitions. Six locations have been selected to evaluate the controls on the carbon and oxygen isotopic composition of the Badenian gypsum-associated limestones of the Tyras Formation in West Ukraine. At three locations marine limestones overlie the gypsum, at one location (Anadoly) the gypsum-associated limestones are polygenic, and at two locations (Pyshchatyntsi and Lozyna) gypsum deposits are lacking. The studied limestones have originated as primary, mostly peloidal carbonates as well as secondary carbonates formed by hypogene sulphate calcitization. They show a wide range of δ13C (from from -0.9‰ to -39.8‰) and δ18O values (from 0.9‰ to -12.2‰). The Badenian limestones formed in marine environments (either as deposits accumulated at the bottom of the sea or forming the infillings of solution cavities within gypsum) have less negative δ18O values compared to predominantly diagenetic formations. Wide ranges and usually very negative δ13C values and low δ18O values of those limestones indicate that they suffered important meteoric diagenesis as supported by common sparitic fabrics. In addition, a large range of δ13C values even in the group of samples characterized by less-negative δ18O values shows that bacterial sulphate reduction and methane oxidation were active processes in the pore fluids of the Tyras Formation. Very low carbon isotopic compositions (δ13C values from -22 to -40‰) of some sparitic limestones in the studied sections indicate the occurrence of oxidized methane within the diagenetic environment. Accordingly, the isotopic signatures of the studied limestones are a combination of both primary and secondary processes, the latter having a primordial importance. The common occurrence of similar negative δ13C and δ18O values in evaporite-related carbonates in other Miocene evaporite basins suggest that extensive dissolution- reprecipitation in diagenetic or vadose-phreatic environments was common in evaporite-related carbonates.