Foraminifers and radiolarians across the Albian-Cenomanian and Cenomanian-Turonian Boundaries (Northern Peri-Tethys)

Changes in morphological diversity and taxonomic composition of late Albian-early Turonian foraminiferal and radiolarian assemblages from the northern Peri-Tethys are considered. Several stages are defined in evolution of planktonic foraminifers: polytaxic (Albian-Cenomanian), oligotaxic (Cenomanian-Turonian boundary period), and polytaxic (Turonian). The Albian-Cenomanian stage was characterized by intense development of rotaliporids representing an intricate group of planktonic foraminifers, which became extinct in the terminal Cenomanian. An intense speciation of the radiolarian genus Crolanium and last occurrences of its most species, the index species C. cuneatum included, was characteristic of the terminal Albian. Spheroid and discoid radiolarians were dominant in the Cenomanian, while the Turonian was marked by intense development of all the radiolarian morphotypes.     

Cenomanian-lower coniacian radiolarian assemblages from the Naiba reference section (Sakhalin)

Reexamination of radiolarians from the Naiba and Bykovo formations of the Naiba reference section (West Sakhalin Mountains) is carried out. Distinguished in the section are the Cromyomma (?) nodosa-Amphipyndax sp. A (terminal early Cenomanian), Cuboctostylus kasinzovae-C. sakhalinensis (Middle Cenomanian), Cuboctostylus trifurcatus-Cassideus yoloensis (terminal middle-late Cenomanian), and Spongodiscus concentricus-Multastrum robustum (late Turonian to early Coniacian probably) assemblages. According to results of comparative analysis for North Pacific regions, concurrent radiolarian assemblages from the Naiba section and California contain up to 40% of species in common, whereas taxonomic similarity with assemblages from Japan is insignifican in contrast.     

The upper Cenomanian–lower Turonian carbonate platform of the Preafrican Trough,Morocco: Biostratigraphic,paleoecological and paleobiogeographical distribution of ostracods

The upper Cenomanian–lower Turonian paleoenvironments of the Preafrican Trough carbonate platform is characterized by analyzing the structure of the ostracod assemblages and the information provided by other groups, and also by linking together the paleontological and geochemical data (detrital influx-redox-paleoproductivity proxies, δ¹³C curve). Two different domains (eastern and western) can be recognized on the platform during the late Cenomanian, before the onset of the OAE2. The western domain corresponds to a low-energy environment developed on a mid and/or outer ramp with hypoxic waters, low detrital influx and low paleoproductivity. The paleoecological assemblages show limited specific diversity but variable density. The ostracods are opportunistic and unspecialized (r strategists), being associated with Buliminidae, surface and intermediate-water planktonic foraminifera, and fishes. The eastern domain corresponds to an inner ramp and/or peritidal environment with oxic waters, low detrital influx and low paleoproductivity, developed in a higher energy environment with paleoecological assemblages showing high diversity but variable density. The ostracods are more specialized (K strategists), being represented by diverse and constant assemblages associated with diversified benthic foraminifera, calcareous sponges and echinoderms, as well as intermediate- and deep-water planktonic foraminifera. The onset of the OAE2 has no influence on the western ostracod assemblages, but leads to the decline of the ostracod fauna and the disappearance of the deep-water planktonic foraminifera in the eastern domain. During the early Turonian, after the OAE2, the platform becomes an outer ramp with increased paleoproductivity, but is associated with a decrease of taxonomic diversity in hypoxic waters. The ostracods are very sparse and unspecialized, associated with siliceous sponges, Buliminidae, surface-living planktonic foraminifera, fishes and pelagic crinoids. Marine paleobiogeographic communication is relatively easy across the carbonate platforms between the Preafrican Trough and other Moroccan regions, as well as between Morocco and different parts of the South Tethyan and East Atlantic margins belonging to the Cenomanian–Turonian South Tethyan Ostracod Province (STOP). Thirteen new species are described: Cytherella tazzouguertensis n. sp., Bairdiacypris chaabetensis n. sp., Bythocypris amelkisensis n. sp., Pontocypris tadighoustensis n. sp., Procytherura? elongatissima n. sp., Loxoconcha akrabouensis n. sp., Hemiparacytheridea sagittaemucronata n. sp., Rehacythereis errachidiaensis n. sp., Rehacythereis zizensis n. sp., Veenia (Nigeria) tardaensis n. sp., Veenia (Nigeria) mediacostarobusta n. sp., Xestoleberis? preafricanensis n. sp., and Xestoleberis circinatus n. sp.     

Radiolarians from Upper Jurassic (Middle Oxfordian and Upper Kimmeridgian) deposits of Yaroslavl oblast

The middle Oxfordian and late Kimmeridgian radiolarian assemblages from Upper Jurassic deposits of Yaroslavl oblast are studied for the first time. The middle Oxfordian assemblage is dominated by stauraxonic morphotypes of genera Paronaella and Pseudocrucella occurring in association with discoid forms. Nassellarian radiolarians are very rare in this assemblage of extremely low taxonomic diversity, which is lacking spheroidal morphotypes. The late Kimmeridgian assemblage is more diverse in morphological and taxonomic aspects. It includes spheroidal forms, those of the family Pantanelliidae Pessagno inclusive, and more frequent nassellarian species, but stauraxonic radiolarians are less abundant in its composition. This assemblage is comparable to a considerable extent with the Kimmeridgian radiolarians from Moscow oblast, being of the South Boreal type according to its composition.     

Lamniform sharks from the Cenomanian (Upper Cretaceous) of Venezuela

Sampling of Cenomanian fossil-rich horizons within the La Luna Formation of two localities in the Zulia and Trujillo states (northern Venezuela) yielded numerous shark teeth belonging to various species within the order Lamniformes (Mackerel sharks). Twelve lamniform species were identified including three new species (Squalicorax lalunaensis sp. nov., Squalicorax moodyi sp. nov., Acutalamna karsteni gen. et sp. nov.) and the genus Microcarcharias gen. nov. is proposed to accommodate with the peculiar morphology of the small-sized odontaspidid M. saskatchewanensis. Other taxa reported here include Cretoxyrhina mantelli, Cretolamna sp., cf. Nanocorax sp. and five Squalicorax species left in open nomenclature. This is the first report of chondrichthyans from the mid-Cretaceous of Venezuela and one of the few records of this group from the Cenomanian of South America. The composition of these assemblages suggests some degree of endemism in the La Luna Sea but also possible connexions with the Western Interior Seaway. One of the most striking features of these assemblages is the high anacoracid diversity (eight species) despite the corresponding outer shelf/upper slope palaeoenvironments of the La Luna Formation. The high diversity of these opportunistic predators is probably related to the high diversity of medium to large marine vertebrates that provided food resources.     

Radiolarians of the upper Cenomanian and lower Turonian from deposits of the Ananuri Formation, the western Caucasus (Lazarevskoe area)

Diverse radiolarians (over 70 species) are detected in cherty rocks above the bituminous shale horizon, the marker of anoxic event OAE-2 recorded across the Cenomanian-Turonian boundary in the upper part of the Ananuri Formation of flyschoid deposits, the Lazarevskoe area of the western Caucasus. The radiolarian assemblages studied are comparable in composition with radiolarians from concurrent Cenomanian-Turonian boundary strata in other Mediterranean regions (e.g., in the Crimea and Turkey). The lower radiolarian assemblage includes index species Dactyliosphaera silviae of synonymous Cenomanian zone. Alievium superbum present in the upper assemblage is index species of the relevant Turonian zone. Within the studied flyschoid sequence, sediments indicative of the above event (bituminous shales and cherts) are confined to upper elements of flysch rhythms.     

Some aspects of Cretaceous ostracod biostratigraphy of South Africa and relationships with other Gondwanide localities

One hundred and thirty-six species, representing 67 genera have been recorded from the late Jurassic-Maastrichtian marine sediments of South Africa. The faunas show a major dichotomy across a regionally-developed late Cenomanian-early Coniacian hiatus with the Portlandian-Cenomanian Cytheruridae/Progonocytheridae/Schizocytheridae dominated faunas being replaced in the Coniacian by Trachyleberididae/Brachycytheridae/Schizocytheridae dominated faunas. Comparison with other Gondwanide localities shows that the two South African basins from which ostracods have been described (Outeniqua and Natal/Zululand) formed part of a Callovian-Cenomanian South Gondwana ostracod province that stretched from the Neuquen Basin of Argentina to Madagascar/Tanzania/Kutch and west Australia. The most characteristic and cosmopolitan forms within this province belong to the Majungaella/Amicytheridea/Progonocythere group, along with Arculicythere in the Aptian-Cenomanian.In Tanzania, (the only locality of the old South Gondwana province where the succession is complete) these assemblages are replaced in the Turonian by the influx of Brachycythere, and Cythereis and various other trachyleberids. Changes of a similar nature are seen whenever marine sedimentation resumed after the local “mid” Cretaceous hiatus (South Africa, India, Argentina). Argentina differs in not having Brachycythere, whose rapid appearance in the West Indian Ocean basin soon after its earliest record in Brazil, is attributed to the destruction of the barrier at the eastern end of the Walvis Ridge/Rio Grande Rise in late Cenomanian or early Turonian times. Despite this common element with Brazil and West Africa, the South African Coniacian to Maastrichtian faunas are closer to those of Tanzania and Australia than they are to either Argentina or Brazil/West Africa. In Zululand they show evidence of a steady increase in water depth, leading to the establishment of progressively more diverse cytheracean populations, with a particularly large increase across the Santonian/Campanian boundary.     

Inoceramid bivalves and biostratigraphy of the upper Albian and lower Cenomanian of the United States Western Interior Basin

Inoceramid bivalves of the upper Albian and lower Cenomanian of the United States Western Interior are revised, Eleven species-level taxa and three genera are described. Two new species, Gnesioceramus mowriensis, characterizing the Mowry Shale of the early, but not the earliest, Cenomanian, and Posidonioceramus merewetheri, of the lower Cenomanian, and on new genus, Posidonioceramus, are recognised. The Western Interior inoceramid species from this interval are strongly endemic and are not good tools for long-distance correlations, although they are very effective in regional dating.In terms of the inoceramid biostratigraphy, middle and upper parts of the upper Albian can be referred to the Gnesioceramus Biozone, represented by G. comancheanus (Cragin) and G. bellvuensis (Reeside). These taxa are endemic to the Western Interior and some adjacent areas (Gulf Coast; Greenland?), but are closely allied to the cosmopolitan species, Gnesioceramus anglicus (Woods). At approximately the Albian-Cenomanian boundary, the endemic clade of ‘Inoceramus’ nahwisi appears, now referred to the newly erected Posidonioceramus, resulting in a distinct P. nahwisi biozone. This zone corresponds to the lower part of the ammonite Neogastroplites’ stratigraphic range. Gnesioceramids re-appear in the early Cenomanian. Close to base of the Cenomanian, for the first in the Western Interior, the genus Inoceramus, represented by Inoceramus irenensis Warren and Stelck, 1958, apparently immigrated into the Western Interior Basin.The Western Interior inoceramids do not allow for direct correlation to chronostratigraphic standard subdivision. The Albian-Cenomanian boundary, as earlier recognized on geochronologic correlations and confirmed, to some extent, based on ammonites, may approximately be located close to the appearance level of the genus Posidonioceramus.     

Turonian cephalopods (ammonoids and a nautiloid) from the Wadi Daya Formation of the Talerzha Basin (South Riffian Ridges Domain,northern Morocco)

The Wadi Daya Formation, or the Calcaires crayeux of the older literature, attains a thickness of 10–40 m in the Talerhza Basin of the South Riffian Ridges. Previously, this unit was first dated as “Vraconian” (i.e., late upper Albian), but then reinterpreted as Cenomanian-Turonian and Cenomanian-Coniacian on the basis of foraminiferal and ostracod assemblages, respectively. Here, we record for the first time in the South Riffian Ridges, some typically Turonian ammonoids and a nautiloid species, namely Romaniceras (Yubariceras) cf. ornatissimum (Stoliczka), Spathites (Jeanrogericeras) cf. reveliereanus (Courtiller), Neoptychites cephalotus (Courtiller), Pachydesmoceras linderi (de Grossouvre), Lewesiceras peramplum (Mantell) and Angulithes galea (Fritsch, in Fritsch & Schlönbach). These species are herein described and illustrated. In view of these data, the underlying Marnes et marno-calcaires jaunes Formation, formerly dated as “Vraconian”, could in fact be of a middle to late Cenomanian date, in accordance with the age assignment based on planktonic foraminifera. Deposition of the overlying Marnes jaunes Formation, previously dated as Cenomanian-“Senonian”, probably started during the latest Turonian or earliest Coniacian.     

The biotic crisis across the Oceanic Anoxic Event 2: Palaeoenvironmental inferences based on foraminifera and geochemical proxies from the South Iberian Palaeomargin

Open marine sediments deposited during the Cenomanian–Turonian transition are well exposed in the Spanish Baños de la Hedionda section (Betic Cordillera, South Iberian Palaeomargin). Analysis of foraminiferal assemblages and geochemical proxies allow inferences on the impact of the Oceanic Anoxic Event 2 (OAE2) in this area of the western Tethys. Three main intervals have been identified corresponding to different lithological units and biozones. (1) The top of the Capas Blancas Member (Rotalipora cushmani Biozone) represents the pre-extinction phase with diverse foraminiferal assemblages and well developed water-column tiering, well-oxygenated, oligotrophic deep-waters and oxygenated to poorly oxygenated, mesotrophic surface-waters. Foraminiferal opportunist species point to a minor event with dysoxic conditions preceding the OAE2. (2) The black radiolaritic shales (Whiteinella archaeocretacea Biozone) consist of a foraminiferal-barren interval, except for the lowermost centimetres where planktic surface-dweller opportunists are common. Redox sensitive elements (Cr/Al, V/Al, U/Th, Mo_EF, Mo_aut, U_EF and U_aut) and increased TOC values reflect oxygen depleted conditions related to the OAE2. The increase in P/Ti values at the base of this stratigraphic interval indicates an abrupt increase in productivity. High concentrations of radiolarians are congruent with high surface productivity probably related to changes in oceanic circulation and enhanced upwelling currents, as well as subsequent shallowing of the oxygen-minimum zone. The increase in Mo_EF and Mo_aut towards the top of the black radiolaritic shales indicates temporal euxinic conditions. (3) A slow, bottom-up recovery of foraminiferal assemblages is inferred at the base of the Boquerón Member (Helvetoglobotruncana helvetica Biozone), with seafloor recolonization by benthic foraminifera being recorded previous to the water column colonization by planktic forms, mainly by intermediate-dwellers typical of mesotrophic waters. The subsequent proliferation of surface-dweller opportunists and deep-dweller opportunists adapted to mesotrophic to eutrophic conditions, and the decrease in planktic foraminiferal diversity, may indicate the persistence of poorly oxygenated conditions in the water column towards the lower-middle part of the H. helvetica Biozone.     

The heterodont bivalve Maghrebella forgemoli (Coquand, 1862) from Cenomanian of Batna,northeastern Algeria: Palaeobiogeography,biostratigraphy and palaeoenvironment

In the northern Aurès Range near Batna, Algeria, the Cenomanian Smail Marls Formation consists of fossiliferous deposits rich in diverse benthic macrofauna, mostly dominated by bivalves, among them the carditid Maghrebella forgemoli (Coquand, 1862). Almost exclusively Cenomanian, the abundance zone of Maghrebella forgemoli is in the higher levels of Lower Cenomanian, extending from the Sharpeiceras schlueteri zone to the Mantelliceras dixoni zone and corresponds to a limited circalittoral interval with relatively low energy, soft substrata, and relatively cold temperatures. The distribution of Maghrebella forgemoli in Mountains of Batna evidences bathymetric variation controlled by the tectonic activity affecting the ante-Triassic and the Upper Cretaceous substrata and generating a system of tilted blocks, at the beginning of the uppermost Albian-Cenomanian and Turonian, in the eastern Atlasic domain that extends to central Tunisia.     

Late Aptian angiosperm pollen grains from Patagonia: Earliest steps in flowering plant evolution at middle latitudes in southern South America

The angiosperm pollen record from the Anfiteatro de Ticó and Punta del Barco formations (Baqueró Group) is reported. The relevance of these floras is that they are accurately dated as late Aptian, and one of the oldest floras southern South America with fossil angiosperms. Twelve samples were studied, showing Clavatipollenites and Retimonocolpites as dominant types. A new species, Jushingipollis ticoensis sp. nov., is proposed. A doubtful angiosperm pollen grain, Lethomasites sp., is also identified and described. A multivariate analysis of similarities between different Early Cretaceous angiosperm pollen assemblages suggests that the Baqueró Group assemblages have great similarities with other coeval units from Argentina, Australia and United States, which were located in a similar paleolatitude.     

Radiolarians of the Volgian and Berriasian stages of the North of Central Siberia

The stratigraphic distribution of radiolarians in the Nordvik reverence section of the Volgian Stage was studied and analyzed. The Arctocapsula magna Bragin assemblage of the middle Volgian and the Arctocapsula perforata Bragin assemblage of the late Volgian-early Berriasian are distinguished in the section. Both assemblages are dominated by nassellarian radiolarians of the family Echinocampidae Bragin, which are known at present only from the Arctic and Boreal regions.     

Siliceous and organic-rich sedimentation during the Cenomanian–Turonian Oceanic Anoxic Event (OAE2) on the northern margin of Africa: an evidence from the Bargou area, Tunisia

The late Cenomanian–early Turonian deposits in Tunisia recording the OAE2 event are commonly attributed to the Bahloul Formation. These deposits are composed of dark clayey limestone and organic-rich black shales with abundant planktic foraminifera. At the Bargou area, Oued Kharroub section, these organic-rich deposits include siliceous beds with abundant radiolarians recalling the “Livello Bonarelli”. A total of 25 radiolarian species are identified with a maximum of 18 species per sample. Moreover, the species skeleton preservation is usually poor to moderate in the most studied samples [estimated preservation index (PI) values ranging between 4 and 6]. Two successive assemblages are distinguished. The oldest one (R_I) is dominated by nassellarians, which includes mainly Stichomitra, Pseudodictyomitra and Rhopalosyringium genera. It is included within the upper part of foraminiferal Rotalipora cushmani Zone and lower part of Whiteinella archaeocretacea zone. In contrast, the youngest assemblage (R_II), which belongs to the upper part of the W. archaeocretacea zone and the earliest Turonian Watinoceras ammonite assemblage, is dominated by spumellarians and includes mainly Archaeocenosphaera, Cavaspongia, Pseudoeucyrtis and Pyramispongia genera. In addition, major and trace elements are analysed to test whether the geochemical record was synchronous to the biotic event or not. Thus, selected crossplots, Al₂O₃ vs. SiO₂ and Al₂O₃ vs. TiO₂, are used to evaluate the detrital input, and V/Cr vs. V/(V?+?Ni) and U/Th vs. V/(V?+?Ni) are used to evaluate the bottom redox conditions and the primary productivity within the Bahloul Formation. A strong Si/Al increase is marked in the lower part of the siliceous and organic-rich Bahloul Formation that could be explained by a local increase in upwelling-related biogenic SiO₂ (silica-secreting organisms). Relative low abundance of terrigenous-related Ti/Al and K/Al ratios and enrichment of some productivity proxies such as Ba (organic matter related trace elements) suggests that the Bahloul was of relatively elevated primary productivity and minimal detrital input. Enrichments in redox-sensitive trace metals U and V in the Bahloul Formation deposits and redox indices, such as V/(V?+?Ni), U/Th and V/Cr, indicate that oxygen-restricted conditions prevailed during the late Cenomanian–earliest Turonian times and correlate well with relative abundances of some radiolarian and foraminiferal paleo-environmental indicators. In addition, indicators of detrital flux variations are used. Al₂O₃ shows a slight positive correlation with TiO₂ and a less distinct correlation with SiO₂.     

Nonmarine Cretaceous palynology of northern Kordofan,Sudan, with notes on fossil Salviniales (water ferns)

A palynological investigation of 164 samples from 18 water wells in northern Kordofan, Sudan, enabled the recognition of five informal zones based on pollen and spore assemblages ranging in age from Albian to Maastrichtian. The youngest (late Campanian-Maastrichtian) assemblages are restricted to the Bagbag Basin, whereas Albian-Cenomanian (to Turonian) sediments are widespread to the east and west of the Bagbag area. Impressions of Salvinia floating leaves from outcrops of the upper Hamrat el Wuz Formation, western part of the study area, are among the oldest occurrences of this water fern and indicate a Campanian-Maastrichtian age for these sediments.The vertical distribution of hygrophilous (pteridophytic spores) versus xerophilous (ephedroids and possibly small, weakly sculptured tricolporates) elements in the palynofloras suggests widespread moist or even aquatic habitats in the Albian-Cenomanian and Campanian-Maastrichtian. A shift towards drier conditions occurred in the late Cenomanian-Turonian. Throughout the Cretaceous, however, there may have been extensive arid/semiarid areas of non-deposition and seasonally dry periods. Some characteristics of the local palynofloras are attributed to its inner continental position. Rare Albian-Cenomanian and Campanian-Maastrichtian dinoflagellates could be interpreted as lacustrine phytoplankton rather than as evidence for marine influence.     

Anatomy of the stratigraphical boundary between the Arnager Greensand and Arnager Limestone (Upper Cretaceous) on Bornholm,Denmark

The complex boundary between the Arnager Greensand Formation and the Arnager Limestone Formation on the island of Bornholm (Denmark) has been studied for almost a century. Despite this effort, the hiatus represented by the boundary remains poorly constrained. Using a considerable number of processed samples and thin sections the uppermost Arnager Greensand Formation is confirmed as Thalmanninella reicheli Zone age (early Middle Cenomanian) and the overlying Arnager Limestone Formation is probably early Coniacian in age. No evidence of macrofossil and microfossil assemblages indicative of the late Cenomanian or the Turonian have been recorded and there is no palaeontological or sedimentological evidence of the global late Cenomanian (Bonarelli or OAE 2) anoxic event. The significant mid-Cenomanian to early Coniacian hiatus reflects a period of sediment starvation along the line of the Sorgenfrei-Tornquist Zone in the vicinity of Bornholm.     

Upper cenomanian ammonites from the environs of Saumur,and the provenance of the types of Ammonites vibrayeanus and Ammonites geslinianus

Ammonite faunas consisting of Neolobites vibrayeanus (d'Orbigny), Calycoceras (Calycoceras) naviculare (Mantell), C. (Lotzeites(?)) sp., Pseudocalycoceras lattense Thomel, Metoicoceras geslinianum (d'Orbigny) and Euomphaloceras septemseriatum (Cragin) from Saumur, within the type area of the Turonian stage, are described from the collections of the Château de Saumur. They allow the recognition of two Upper Cenomanian horizons at Saumur, the one equivalent to the Sciponoceras gracile/Metoicoceras geslinianum Zone as developed in the Sables à Catopygus obtusus/Sables de Bousse of the Cenomanian stratotype; the other, older assemblage equates with the Calycoceras naviculare/Eucalycoceras pentagonum Zone fauna known from the Marnes à Ostracées of the type Cenomanian. From lithological comparisons it is suggested that this area is the source of the types of both Metoicoceras geslinianum and Neolobites vibrayeanus, which are redescribed.     

藏南泽当卡多地区中生代放射虫动物群研究及其地质意义

雅鲁藏布江蛇绿岩带一直以来被认为是新特提斯洋岩石圈的残留,其与雅鲁藏布江缝合带内相关的海相地层共同记录了新特提斯洋的演化过程以及印度—欧亚板块的碰撞过程。位于藏南泽当西南卡多附近的硅质岩剖面中发现有保存较好的中生代放射虫化石,鉴定出放射虫31属39种,识别出4个放射虫组合,并将之与邻区及西特提斯地区放射虫化石带进行对比确定其时代:Alievium longispineum-Transhsuum maxwelli组合,晚巴通期—早卡洛夫期;Hsuum maxwelli-Triactoma mexicana组合,晚卡洛夫期—牛津期;Holocryptocapsa hindei-Hiscocapsa grutterinki组合,晚巴雷姆期—早阿普特期;Hemicryptocapsa polyhedra-Obeliscoites giganteus组合,晚阿尔布期—赛诺曼期。卡多硅质岩中所含放射虫组合可为泽当蛇绿岩的形成时限及新特提斯洋的演化提供重要的微体古生物依据。     

Late Pleistocene vegetation of Kings Canyon,Sierra Nevada,California

Seven packrat midden samples make possible a comparison between the modern and late Pleistocene vegetation in Kings Canyon on the western side of the southern Sierra Nevada. One modern sample contains macrofossils and pollen derived from the present-day oak-chaparral vegetation. Macrofossils from the six late Pleistocene samples record a mixed coniferous forest dominated by the xerophytic conifers Juniperus occidentalis, Pinus cf. ponderosa, and P. monophylla. The pollen spectra of these Pleistocene middens are dominated by Pinus sp., Taxodiaceae-Cupressaceae-Taxaceae (TCT), and Artemisia sp. Mesophytic conifers are represented by low macrofossil concentrations. Sequoiadendron giganteum is represented by a few pollen grains in the full glacial. Edaphic control and snow dispersal are the most likely causes of these mixed assemblages.The dominant macrofossils record a more xeric plant community than those that now occur on similar substrates at higher elevations or latitudes in the Sierra Nevada. These assemblages suggest that late Wisconsin climates were cold with mean annual precipitation not necessarily greater than modern values. This conclusion supports a model of low summer ablation allowing for the persistence of the glaciers at higher elevations during the late Wisconsin. The records in these middens also suggest that S. giganteum grew at lower elevations along the western side of the range and that P. monophylla was more widely distributed in cismontane California during the Pleistocene.     

Foraminiferal biostratigraphy of the Albian and Cenomanian sediments in the Polish part of the Pieniny Klippen Belt,Carpathian Mountains

Seven local biostratigraphic zones have been distinguished in the Albian and Cenomanian sediments of the Pieniny Klippen Belt: Hedbergella assemblage (Assemblage Zone, AZ), R. subticinensis-R. ticinensis (Concurrent Range Zone, CRZ), R. ticinensis- P. praebuxtorfi (CRZ), R. ticinensis- P. buxtorfi (Partial Concurrent Range Zone, PCRZ), P. buxtorfi- R. appenninica (CRZ), R. appenninica (Partial Range Zone, PRZ) and R. reicheli- R. green-hornensis (PCRZ), The zones are tentatively correlated with the ortho- and parastratigraphic zones of the Albian and Cenomanian. Three palaeoecological associations have been distinguished: “Czorsztyn”, shelf-upper slope, large proportion of nodosarids and miliolids; “Pieniny A” middle part of slope, oligotaxic planktonic assemblages dominant; “Pieniny B”, depth similar to that of “Pieniny A”, larger proportion of agglutinated foraminifers. All fall within the “Marssonella” association sensu Haig, 1979, Haig, 1979. Layers of black shales, interpreted to reflect Cretaceous oceanic anoxic events, are correlated between successions of the Pieniny Klippen Belt, and their biostratigraphical position is determined.