Nonmarine Strata Research Articles

A new freshwater lonchidiid hybodontiform shark (Chondrichthyes, Elasmobranchii) from the Upper Triassic Momonoki Formation in Yamaguchi, Japan

ABSTRACT We describe an assemblage of isolated hybodontiform shark teeth from the nonmarine Upper Triassic (Carnian) Momonoki Formation in the town of Ominecho in Mine, Yamaguchi, Japan. These teeth were first reported in 1996 and tentatively referred to the genus Hybodus, but their taxonomy was not rigorously evaluated in an apomorphy-based context, and they have since been mostly overlooked. Herein, we assign them to a new species, Parvodus ominechonensis, based on a combination of synapomorphies of the lonchidiid genus Parvodus and autapomorphic character states. A diversity of Triassic hybodontiforms is known from Japan, but of these, Parvodus ominechonensis sp. nov. is the only taxon known from nonmarine deposits and the first reported occurrence of Lonchidiidae. Parvodus ominechonensis fills a gap in the stratigraphic record of Parvodus between occurrences in Middle Triassic (Anisian) and Middle Jurassic (Bajocian) strata. The global Triassic record of Parvodus comprises Parvodus huizodus from the Olenekian of China, Parvodus sp. from the Anisian of China, and Parvodus ominechonensis from the Carnian of Japan, of which Parvodus ominechonensis and Parvodus huizodus are known from nonmarine deposits. After the Triassic, Parvodus is known from marine and nonmarine strata across Laurasia and in South America until its extinction during the Early Cretaceous. This suggests that Parvodus may have originated in freshwater habitats in the South China region of Pangea following the end-Permian mass extinction and diversified throughout the Triassic in present day East Asia before attaining a global distribution later in the Mesozoic. http://zoobank.org/urn:lsid:zoobank.org:pub:42B4D1C1-F4BE-4296-896B-01B048BDE25F

Basin formation, magmatism, and exhumation document southward migrating flat-slab subduction in the central Andes

The Central Andean Plateau is the largest plateau formed in a non-collisional setting and is taller, wider, has thicker crust, and has greater retroarc shortening than any other region of the modern Andes. It also hosts some of the thickest Cenozoic strata in the Andes, which were deposited synchronously with punctuated widening and narrowing of the magmatic arc. Multiple hypotheses have been advanced to explain these unique characteristics, yet the detailed, plateau-scale Cenozoic basin history needed to test these hypotheses remains unavailable and therefore has not been integrated into the established records of deformation and magmatism. Here we synthesize new detrital zircon maximum depositional ages (MDAs) and sediment provenance analysis of non-marine strata from ∼15°–16.5°S with existing records of sediment accumulation, deformation, and magmatism from ∼14°–24.5°S to develop a model of the Eocene–early Miocene evolution of the Altiplano-Puna plateau region. Stratigraphic correlations based on the new MDAs show a Paleocene–Eocene unconformity/condensed section followed by resumption of rapid sediment accumulation. Rapid sediment accumulation resumed at 46–43 Ma at 15–16°S, at 36 Ma at 18°S, and as young 19 Ma at ∼23°S. Provenance data presented herein indicate that Eastern Cordilleran detritus appeared in Altiplano strata at progressively younger ages to the south. The southward progression of this basin reorganization proceeded in lockstep with initiation of exhumation in the Eastern Cordillera, and also a lull in the magmatic arc followed by widespread volcanic flare-up. We present a model in which the observed stratigraphic hiatus, along with the magmatic lull and flare-up, orogenic widening, and high-magnitude shortening, are upper plate responses to shallowing and resteepening of an late Paleocene–early Miocene flat slab beneath the Altiplano-Puna plateau. In the proposed model initial slab flattening was driven by late Paleocene–early Eocene subduction of buoyant oceanic crust: potentially a Manihiki Plateau Conjugate. Subsequently, southward shallowing and resteepening of a late Eocene–early Miocene flat slab beneath the Altiplano-Puna Plateau was driven by subduction of an asperity on the Nazca Plate which we tentatively identify with the Juan Fernandez Ridge. The geographic coincidence of all of these features suggests that the flat slab hydrated and weakened the upper plate lithosphere, thereby facilitating later development of the suite of unique features which characterize the Central Andean Plateau.

Litologie a paleopůdy klikovského souvrství ve vrtu 2140 01T1 Dunajovice, třebonská pánev

The 2140 01T1 borehole sampling the Late Cretaceous non-marine strata of the Klikov Formation in the central part of the Třeboň Basin in southern Bohemia provided ~ 70 m thick alluvial succession composed of alternating sandstone and mudstone intervals that overlays deeply weathered crystalline basement. The mudstone interval in the lower part of the Klikov Formation is separated by sandy layers into several 2–4 m thick fining-upward units. The sharp-based sandy layers with fusain, carbonized stems and rip-up clasts of underlying mudstone are interpreted as avulsion deposits. They grade upwards into heterolithic sand-silt sequence and mottled massive mudstone with burrows, rhizohalos and variably developed pedogenic features. Such cyclic arrangement probably reflects autogenic processes on distal floodplain with episodic deposition and upward increasing subaerial exposition and pedogenic overprint. In the middle to upper parts of the Klikov Formation up to 6 m thick channel sandbodies with sharp erosional bases cutting into the underlying laminated sand-silt heteroliths of channel levee deposits occur. The thickness of the single-storey sandbodies corresponds usually to c. 2 m which suggests up to 3 m deep channels during bankfull discharge. The thicker multi-storey sandbodies record channel amalgamation on the alluvial ridge or shallow paleovalley fillings. The sandbodies grade upwards to massive mudstones of abandoned channel fills and floodplain deposits. These floodplain units are up to 8 m thick and consist of variegated massive mudstones interrupted by discrete up to 1 m thick fining upward layers of rippled sandstone representing crevasse splay deposits. Depositional context including preserved levee deposits, abandoned channel fillings and floodplain finegrained deposits suggests rather higher sinuosity of the formative rivers. Palaeosol profiles represent pedogenically modified floodplain fines with gradational bases and sharp erosive top surfaces. At least 10 palaeosols were identified in the measured section, forming mostly discrete profiles up to 2 m thick consisting of several B-horizons that differ in the degree of the soil structure development, colour, mottling, grain size, presence of clay hypocoatings and bioturbation index. The most common Bw horizons form lower parts of the profiles and have no or only a weakly developed angular blocky structure (ABS). The typical mottling is caused by a hierarchical system of vermicular greenish-grey reduction rhizohalos, that may be filled by silt to sand or illuviated clay hypocoatings and probably follow the original plant root system. Some patches have diffuse orange rims of iron oxides, probably represented by goethite. Mudstone of Bsst horizons displays well-developed ABS with rare wedge-shaped peds and contains a number of illuviated clay skins and redox depletions. Vertic features like fine cracks filled by sand are common, and slickensides with clay hypocoatings occur rarely. Mudstones of Bt horizons contain a number of illuviated clay hypocoatings filling root channels or interpedal cracks, while the Bss horizons exhibit well-developed ABS with slickensides and contain a number of vertical cracks filled by sandy grains. Palaeosol profiles represent mainly argillisols and vertic argillisols with transitions to argillic vertisols. Poorly developed argillic to vertic protosols are also common. Palaeosol profiles differ mainly in the degree of structural development/maturity, which is given by various lengths of exposition to similar climatic conditions. Vertical distribution of palaeosols reflects their position in the alluvial landscape with locally specific hydromorphic conditions rather than a distinct climatic trend. Most of palaeosols exhibits downprofile translocation of clay (illuviation) leading to the formation of argillic horizon, which typically develop on stabilized landscape in humid climate with seasonal moisture deficit.

Refined geochronology and revised stratigraphic nomenclature of the Upper Cretaceous Wahweap Formation, Utah, U.S.A. and the age of early Campanian vertebrates from southern Laramidia

The Western Interior of North America preserves one of the most complete successions of Upper Cretaceous marine and non-marine strata in the world; among these, the Cenomanian-Campanian units of the Kaiparowits Plateau in southern Utah are a critical archive of terrestrial environments and biotas. Here we present new radioisotopic ages for the Campanian Wahweap Formation, along with lithostratigraphic revision, to improve the geological context of its fossil biota. The widely accepted informal stratigraphic subdivisions of the Wahweap Formation on the Kaiparowits Plateau are herein formalized and named the Last Chance Creek Member, Reynolds Point Member, Coyote Point Member, and Pardner Canyon Member (formerly the lower, middle, upper, and capping sandstone members respectively). Two high-precision U-Pb zircon ages were obtained from bentonites using CA-ID-TIMS, supported by five additional bentonite and detrital zircon LA-ICP-MS ages. Improved geochronology of the Star Seep bentonite from the base of the Reynolds Point Member via CA-ID-TIMS demonstrates that this important marker horizon is over a million years older than previously thought. A Bayesian age-stratigraphic model was constructed for the Wahweap Formation using the new geochronologic data, yielding statistically robust ages and associated uncertainties that quantifiably account for potential variations in sediment accumulation rate. The new chronostratigraphic framework places the lower and upper formation boundaries at 82.17 +1.47/-10.63 Ma and 77.29 +0.72/-0.62 Ma, respectively, thus constraining its age to the first half of the Campanian. Additionally, a holistic review of known vertebrate fossil localities from the Wahweap Formation was conducted to better understand their spatio-temporal distribution including revised ages for early members of iconic dinosaur lineages such as Tyrannosauridae, Hadrosauridae, and Centrosaurinae. Chrono- and lithostratigraphic refinement of the Wahweap Formation and its constituent biotic assemblages establishes an important reference for addressing questions of Campanian terrestrial paleoecology and macroevolution, including dinosaur endemism and diversification throughout western North America. • New high-precision age for the Star Seep bentonite extends age of the Wahweap Fm. • Subdivisions of the Wahweap Formation are formally recognized. • A detailed age-stratigraphic model was generated including uncertainty. • Robust ages with uncertainty produced for any stratigraphic level in the formation. • Oldest members of key dinosaur lineages found to be older than previously thought.

Characterization of organic matter from the Cretaceous sedimentary and volcano-sedimentary strata from Livingston Island, Antarctic Peninsula: Insights from organic petrology, molecular proxies and carbon and hydrogen isotopes

Rock samples from the Early to Late Cretaceous marine and non-marine strata of Livingston Island, South Shetland Islands, Antarctica, were studied. Organic matter (OM) originates predominantly from terrestrially-derived organic particles. Mostly highly fragmented plant remains, and locally vitrinite/semifusinite as part of plant compressions/imprints or thin vitrain/fusain lenses, are present. Bulk geochemical results indicate Type III kerogen with poor hydrocarbon generation potential. Tmax and molecular proxies (i.e hopane and sterane isomerization ratios, MPI-1, etc.), together with the local presence of oily droplets, argue for an early oil window maturity, probably caused by regional volcanic activity. In contrast to the results of petrography and Rock-Eval pyrolysis, molecular composition of extractable OM is dominated by short-chain n-alkanes, saturated fatty acids (FAs) and n-alkanols implying a major contribution of autochthonous OM. This contradiction is most likely caused by decomposition of OM from plant tissues, the predominance of wood remains (i.e., xylites) and the low input of FAs from cuticular waxes. The presence of terrestrial OM is indicated by plant wax-derived lipids and resinous compounds. Prominent even carbon number predominance in the short-chain n-alkane range argue for deposition/decomposition under reducing environmental settings, most probably caused by high sedimentation rates and quick burial. Terpenoid biomarker compositions indicate contribution from conifers, whereas input from phytoplankton/algal organic matter is evidenced by C27 steroids, the presence of 4-methyl steranes and dinosterol. Low concentrations of hopanoids and C15 and C17 branched n-FAs argue for limited bacterial input. Only in one sample from Hannah Point, a difference between the δ13C values of the short-chain versus long-chain n-alkanes was obtained, arguing for mixed OM sources (i.e., autochthonous input, land plants). The presence of charred organic matter in most of the studied samples, together with the considerable concentrations of combustion-derived PAHs, argue for the common occurrence of wildfires within the terrestrial environments. Despite the active volcanic arc settings, the compound specific carbon and hydrogen isotopes do not record significant changes in climatic/hydrological conditions, although some short-term events cannot be ruled out. Instead, the δ13C and δ2H isotopic fractionation is most likely caused by the specific biosynthetic mechanisms of the plants and the global carbon and hydrogen cycles.

Cordilleran Foreland Tectono-Sedimentary Element, Canadian Northern Interior Plains

Abstract Upper Jurassic–Paleocene siliciclastic strata comprise the Cordilleran Foreland Tectono-Sedimentary Element of Canada's northern Interior Plains. These strata record four major packages deposited on top of Paleozoic shelf strata on the NW margin of the Canadian craton. These packages are a Jurassic interval interpreted to record deposition associated with extension at the Arctic Ocean margin, a Lower Cretaceous, dominantly marine, interval deposited on the flexural margin of the foreland basin, and two Upper Cretaceous intervals of west-to-east progradational marine and non-marine strata deposited on the orogenic margin. The full succession has been affected by Cordilleran deformation within the Mackenzie Plain, Franklin Mountains and Colville Hills. Organic-rich shale is documented from Lower and Upper Cretaceous successions but these strata only reach thermal maturity in deeper parts of the basin, close to the Canadian Cordillera. Potential reservoirs exist within sandstone-dominated intervals throughout the succession, although some locally lack a top seal. One natural gas discovery has been reported from Upper Cretaceous sandstone of the Little Bear Formation at the Stewart D-57 well in the southeastern Mackenzie Plain. Oil sourced from Upper Cretaceous shale is reported from the Mackenzie Plain East Mackay B-45 well.

Ostracods from the non-marine Lower Cretaceous interval at Liying section of Luanping basin, North China: A stratigraphic correlation

Non-marine strata of Lower Cretaceous age in western Liaoning and northern Hebei, North China, are famous for its Jehol Biota, including abundant ostracods. However, there are still some controversies about the stratigraphic correlation in these regions, for instance, it is still debated whether the interval from the Liying section of Luanping Basin belongs to the Dadianzi Formation or the member 1 of the Xiguayuan Formation. Ostracods act as an important tool for the correlation of the stratigraphy within or between basins. Here we report and illustrate the ostracods from the Liying section in detail for the first time, and aim to determine the section's stratigraphic correlation. Results show that, the Liying section has a thickness of 157.65 m and can be divided into 33 layers. Ostracods from this section are mainly distributed in the lower and middle part, and 7 genera and 13 species have been preliminarily recognized. These ostracod species can be summarized as the Cypridea-Limnocypridea-Lycopterocypris Assemblage Zone temporarily. Based on the identified ostracods, occurrence of other abundant representative fossils of the Jehol Biota, and isotope dating results, the major interval of the Liying section should be assigned to member 1 of the Xiguayuan Formation, and can be correlated with the Yixian Formation from western Liaoning.

New age constraints on the Late Cretaceous lower Williams Fork Formation, Coal Canyon, Colorado

The precise age of terrestrial sediments in the Late Cretaceous Williams Fork Formation of western Colorado is poorly constrained due to a paucity of radiometric data. Sanidine and zircon dating of a volcanic ash encased in coal (i.e., the Coal Canyon ash) within the Cameo-Wheeler coal zone of the lower Williams Fork Formation in Coal Canyon, Colorado provides an important new age constraint for the southwestern Piceance Basin. A 10-30 cm thick, light gray, clayey mudstone encased in coal was sampled for both zircon U-Pb and sanidine 40Ar/39Ar geochronology. The presence of numerous euhedral zircon crystals, a lenticular geometry, and a clayey texture suggest that the mudstone is a minimally reworked and slightly altered volcanic ash. Analysis of the euhedral zircon crystals (n=108) in the ash produced a statistically robust U-Pb date with 93 grains yielding a weighed mean age of 74.52 ±0.11 Ma (1σ analytical uncertainty). 40Ar/39Ar sanidine analyses yielded a younger weighted mean age of 73.10 ±0.12 Ma (1σ analytical uncertainty) based on 6 of the 36 grains analyzed. Our preferred age is given by the weighted mean age of the sanidine as it is based on higher precision analyses that can better discriminate older inherited grains that are likely included in the zircon mean-age calculation. Isotopic data for the Coal Canyon ash overlap in age with a K-Ar date of 72.5 ±5.1 Ma for a widespread Williams Fork Formation tonstein, known as the Yampa Bed, found in coal-bearing outcrops and mine workings throughout the northern Piceance and Sand Wash basins and Axial Basin Uplift. Based on the similarity in isotopic age, sedimentologic context and stratigraphic position, we suggest that the Coal Canyon ash and the regionally extensive Yampa Bed are coeval. Additionally, this correlation corroborates that the Cameo-Wheeler coal zone of the Williams Fork Formation in the southwestern Piceance Basin is correlative with the Middle coal zone of the Danforth Hills and Yampa regions. Lastly, this proposed correlation may suggest that the Coal Canyon ash, like the Yampa Bed, correlates with the Baculites reesidei ammonite zone, which is associated regionally with a bentonite dated to 72.94 ±0.45 Ma. Detrital sanidine geochronology of two lower Williams Fork sandstone units that overly the Coal Canyon ash did not produce grains younger than the ash and thus do not quantitatively improve the chronostratigraphy of these specific units. Lastly, the Coal Canyon ash date serves as a basis for future evaluations of the diachroneity of non-marine strata of the Williams Fork Formation.

The Cretaceous stratigraphy, Songliao Basin, Northeast China: Constrains from drillings and geophysics

Abstract The Cretaceous nonmarine sedimentary strata are widespread in Songliao Basin, Northeast China. As the largest oil producer in China, an abundance of data has been generated by the petroleum industry, including sedimentology, seismology, geochemistry, and geochronology in the Songliao Basin. This article reviews the achievements in China Cretaceous Continental Scientific Drilling SK and presents the new results of the China Continental Geothermal Drilling SR1 in stratigraphy and geophysics. The results allow us to establish the relationships among SK-1, SK-2, and SR1, provide some constrains on the tectonic setting of Songliao Basin, and interpret the sedimentary facies and environmental evolution. After stratigraphic correlation of SK and SR boreholes, the result indicates that the geological boundary between the late Cretaceous Mingshui formation and the Paleogene Yi’an formation is at the depth of 115 m. The magnetotelluric sounding anomaly areas are corresponding with the unconformities, which are equivalent to seismic horizon T03, T1, T2, and T3, respectively. In addition, the typical “steer’s-head” geometry in the magnetotellurics indicates that the SLB has experienced five evolution stages.

Nonmarine turtles from the Aguja Formation (Late Cretaceous, Campanian) of Chihuahua, Mexico

Fragments of turtle shell are known from several Upper Cretaceous formations in Mexico, including Corral de Enmedio and Packard Shale, Sonora; Aguja and Cerro del Pueblo, Coahuila; San Carlos, Chihuahua; El Gallo, Baja California; and Ocozocoautla, Chiapas. Turtles are important members of Upper Cretaceous vertebrate assemblages throughout North America and are considered a useful tool to define biogeographic patterns. The Upper Cretaceous sedimentary rocks exposed in the Aguja Formation record the final transgressive/regressive sequence of the Western Interior Cretaceous Seaway and the subsequent transition from a marine to terrestrial environment. The total area of outcrops is small compared to correlative exposures of these strata elsewhere in North America, in spite of this, numerous invertebrate and vertebrate fossils have been collected. The Aguja Formation in Texas preserves one of the southernmost well-studied Upper Cretaceous (Campanian) terrestrial vertebrate faunas in North America; contrary to what happens with the outcrops in northern Chihuahua, where the record of terrestrial vertebrates is scarce and especially those related to Testudines. Non-marine strata of the Aguja Formation do not appear to be present farther south in Mexico, and this is the reason why the Aguja fauna is relevant to documenting latitudinal variation in Campanian continental faunal associations. In this paper, the richness of Upper Cretaceous turtles collected from three localities within the Aguja Formation in Chihuahua is reviewed. Six taxa are recognized based on shell fragments with distinctive sculpture patterns: stem cryptodires, including cf. Baenidae, c.f. Denazinemys nodosa and cf. Compsemys victa, and crown group cryptodires including trionychians (trionchids and Basilemys sp.) and a kinosternoid (cf. Yelmochelys rosarioae). With the recognition of these taxa, new records are reported for the Aguja Formation (e.g. cf. Yelmochelys rosarioae) and Mexico (e.g. c.f. Denazinemys nodosa). The knowledge of Cretaceous turtle richness of the Aguja Formation and Mexico is increased and confirms the proposal of the variability richness along the North American localities. This latitudinal variability suggests that at any time turtles would have had a climatically controlled northern limit of distribution, and the richness of turtles would have decreased as this limit was reached.

P.817 The effects of different length of displacement on the war-related stress induced health outcomes in internally displaced persons in Georgia

Fragments of turtle shell are known from several Upper Cretaceous formations in Mexico, including Corral de Enmedio and Packard Shale, Sonora; Aguja and Cerro del Pueblo, Coahuila; San Carlos, Chihuahua; El Gallo, Baja California; and Ocozocoautla, Chiapas. Turtles are important members of Upper Cretaceous vertebrate assemblages throughout North America and are considered a useful tool to define biogeographic patterns. The Upper Cretaceous sedimentary rocks exposed in the Aguja Formation record the final transgressive/regressive sequence of the Western Interior Cretaceous Seaway and the subsequent transition from a marine to terrestrial environment. The total area of outcrops is small compared to correlative exposures of these strata elsewhere in North America, in spite of this, numerous invertebrate and vertebrate fossils have been collected. The Aguja Formation in Texas preserves one of the southernmost well-studied Upper Cretaceous (Campanian) terrestrial vertebrate faunas in North America; contrary to what happens with the outcrops in northern Chihuahua, where the record of terrestrial vertebrates is scarce and especially those related to Testudines. Non-marine strata of the Aguja Formation do not appear to be present farther south in Mexico, and this is the reason why the Aguja fauna is relevant to documenting latitudinal variation in Campanian continental faunal associations. In this paper, the richness of Upper Cretaceous turtles collected from three localities within the Aguja Formation in Chihuahua is reviewed. Six taxa are recognized based on shell fragments with distinctive sculpture patterns: stem cryptodires, including cf. Baenidae, c.f. Denazinemys nodosa and cf. Compsemys victa, and crown group cryptodires including trionychians (trionchids and Basilemys sp.) and a kinosternoid (cf. Yelmochelys rosarioae). With the recognition of these taxa, new records are reported for the Aguja Formation (e.g. cf. Yelmochelys rosarioae) and Mexico (e.g. c.f. Denazinemys nodosa). The knowledge of Cretaceous turtle richness of the Aguja Formation and Mexico is increased and confirms the proposal of the variability richness along the North American localities. This latitudinal variability suggests that at any time turtles would have had a climatically controlled northern limit of distribution, and the richness of turtles would have decreased as this limit was reached.

Non-marine ostracod biostratigraphy of Cretaceous rift lake deposits (Sousa Basin, Brazil): Paleogeographical implications and correlation with Gondwanic basins

The Cretaceous section of the Sousa Basin represents alluvio-fluvio-lacustrine deposits from rift lakes generated in NE Brazil as a consequence of the West Gondwana break-up process, marked by progressive separation of the African and South American plates. The chronostratigraphic age of the sedimentary succession is controversial due to the few biostratigraphic data available, based on palynomorphs, ostracods and ‘conchostracans’ (Spinicaudata), and taxonomic problems of some of the fossils. Non-marine ostracods (microcrustaceans) are useful index fossils and have been used for a regional biozonation of the lacustrine deposits. Due to this factor non-marine ostracods from the core 2-FC-01-PB, which comprises rocks of the Sousa Formation (Rio do Peixe Group), were analysed. The core 2-FC-01-PB assemblage includes index taxa for biozones RT-002 to RT-005 (Alicenula leguminella, Brasacypris ovum, Cypridea ambigua and Reconcavona swaini), indicating a Berriasian to Hauterivian age (Rio da Serra/Aratu local stages). The previous assignment of a Jurassic age to the early stage of deposition of the Rio do Peixe Group is refuted here. We discuss and revise the stratigraphic range and paleogeographical distribution of relevant index ostracods. Our revised non-marine ostracod biostratigraphy facilitates correlations of non-marine strata of the Sousa Basin with those of Brazilian (Recôncavo, Tucano and Sergipe) and African (Gabon and Congo) sedimentary basins of West Gondwana.

Marine and non-marine strata preserving Ediacaran microfossils

We report the first occurrence of microfossils in Ediacaran strata of the Camaquã Basin. The assemblage includes simple (Leiosphaeridia sp. predominantly) and ornamented acritarchs associated with microbial mats. They are related to the Ediacaran Complex Acanthomorph Palynoflora (ECAP) and Late Ediacaran Leiosphere Palynoflora (LELP) due to the similar morphology and time interval assigned to those assemblages, though the observed specimens are a lot simpler and less diversified. However, different from the usual occurrences, this case study reports Neoproterozoic cosmopolitan communities living in marine (basal unit) and lacustrine (middle units) settings. Fossils within non-marine strata in the Precambrian record are rare. Therefore, this first finding of microfossils in the Camaquã Basin constitutes a new piece of the puzzle related to the history of the Panafrican-Brasiliano basins and shed some light on possible settings where the Ediacaran eukaryotes have evolved.

Evidence for non-marine Jurassic to earliest Cretaceous sediments in the pre-breakup section of the Mentelle Basin, southwestern Australia

The Mentelle Basin, located off the southwestern continental Australian margin, is an under-explored deep-water basin that developed during the breakup of eastern Gondwana in the Middle Jurassic through to the Early Cretaceous. There is a high degree of uncertainty in stratigraphic interpretations of the basin owing to the lack of well and seismic data in the region. As a consequence, there has been a heavy reliance on data from the neighbouring Perth Basin to infer the geological history of the Mentelle Basin. During Expedition 369 of the International Ocean Discovery Program, a single hole was drilled with a rotary core bit to 517.10 m below seafloor at Site U1515 on the continental slope in the eastern Mentelle Basin. The aim was to sample and date the inferred Permian to Jurassic pre-breakup strata. The presence of palynomorphs including Murospora florida and Retitriletes watherooensis in the fluvio-lacustrine succession below the Valanginian breakup unconformity indicates a Jurassic to earliest Cretaceous age for the upper part of the pre-rift sedimentary succession. Notable characteristics of this succession include intervals with high percentages of total organic carbon (up to 44 wt%) and high hydrogen index values (Type I source rocks) associated with an increase in Botryococcus and other freshwater algae that accumulated in shallow lakes and waterlogged floodplains. A possible example of dinoturbation was also noted in this core. The discovery of Jurassic to earliest Cretaceous pre-breakup strata at Site U1515 suggests that Jurassic rifting was not constrained to the western depocentre of the Mentelle Basin, but also extended to a number of depocentres in the eastern Mentelle Basin. This has significant implications for the understanding of the regional tectonic history and the Mentelle Basin’s petroleum potential.Pre-breakup strata sampled in the eastern Mentelle Basin for the first time by IODP Expedition 369Upper Jurassic–Lower Cretaceous non-marine strata below the Valanginian UnconformityHigh TOC’s, high abundances of Botryococcus algae in a few horizons and a possible example of dinoturbationJurassic rifting not constrained to the western Mentelle Basin, but to depocentres in the east

Stratigraphy and vertebrate fauna of the lower shale member of the Aguja Formation (lower Campanian) in West Texas

The lower shale member of the Aguja Formation is one of only a few terrestrial stratigraphic units of early Campanian age in North America. Apart from a prolific microfossil site that yielded the Lowerverse local fauna, the lower shale is sparsely fossiliferous, and very little is known about its larger vertebrate fauna. Most of the specimens collected thus far are fragmentary, but among these are a hybodontid shark, an amiid fish (Melvius sp.), and bothremydid, trionychid, nanhsiungchelyid (Basilemys sp.), and baenid (cf. Denazinemys sp.) turtles. An isolated osteoderm is referable to the alligatoroid crocodylian Deinosuchus sp. A partial skull and skeleton of a goniopholidid crocodyliform is the most complete specimen recovered thus far, and likely represents a new genus and species. The most abundant dinosaur in the fauna is a new genus and species of hadrosaur. A partial pelvis and metatarsus of an ornithomimid dinosaur also likely represents a new taxon. Indeterminate tyrannosaurid, dromaeosaurid, ceratopsid, and nodosaurid dinosaurs are represented. The lower Two Medicine Formation in Montana, lower Wahweap Formation in Utah, and Menefee Formation in New Mexico bear the only other terrestrial vertebrate faunas of broadly comparable age in North America. The Aguja lower shale fauna is allied with ‘southern’ faunas in New Mexico and Utah in sharing the amiid fish Melvius, the baenid turtle Denazinemys, bothremydid turtles, and goniopholidid crocodyliforms. These taxa are absent in para-contemporaneous faunas of Montana and Alberta. Non-marine strata of early Campanian age do not appear to be present farther south in Mexico, and so the lower Aguja fauna is significant in documenting latitudinal variation in early Campanian continental environments.

New Devonian plant fossil occurrences on the New South Wales South Coast: geological implications

Devonian fossil localities are summarised for coastal southeastern Australia, including both marine invertebrates representing a major late Frasnian (Late Devonian) transgression, and plant remains of Middle–Late Devonian age in associated non-marine strata. Lycopsid plant specimens (Leptophloeum) from near Majors Creek, NSW, first documented by Edgeworth David and E. F. Pittman in association with marine fossils to demonstrate a Late Devonian age, are illustrated for the first time. Lycopsid plants of presumed Middle Devonian age are illustrated from three new localities: Yowrie River inland from Cape Dromedary, Tuross River northwest of Narooma and Charlies Forest Road northeast of Braidwood. The Yowrie River occurrence (in float) indicates probable Middle Devonian strata upstream that are not shown on published maps. The Tuross River occurrence is in sheared and folded strata previously mapped as Ordovician, and the Braidwood occurrence demonstrates Devonian black shales adjacent to previously mapped Ordovician. Evidence supporting alternative thrust or simple fold interpretations for the Budawang Synclinorium is discussed, and relevant Ordovician fossil localities are listed.

Cretaceous Stratigraphy of Pakistan

Cretaceous strata of Pakistan yielded many significant fossils of terrestrial ecosystems like poripuch (all caudals are procoelous) lithostrotian titanosaurian sauropods, abelisauroids theropods, mesoeucrocodiles, pterosaurs and gymnosperm stem wood. Both marine and non-marine strata well exposed through the Cretaceous, Jurassic-Cretaceous and Cretaceous-Paleogene boundaries found in Pakistan especially in Indus Basin. Indus Basin represents strata from Precambrian to Recent. Here a glimpse of Cretaceous Stratigraphy of Pakistan is being presented.

A Hope for an Integrated Taxonomy of Fossil and Extant Clam Shrimps

Clam shrimps are large bivalved branchiopod crustacean. They first occurred in the Devonian, and flourished during the Mesozoic in Asia. Fossil clam shrimps play an important role in the subdivision and correlation of non-marine fossil-bearing strata. The phosphatized carapaces or carapace external/internal moulds are the main objects for taxonomical studies. The delicate ornament and the ontogenetically developing morphological patterns on the growth bands of carapaces are the main fossil taxonomic criteria. While modern clam shrimp taxonomy is based on soft body morphological features and molecular data, which could not be found in the fossil records. This makes it difficult to discuss the fossil and modern clam shrimp phylogenetic relationship. Nowadays scanning electron microscopes are widely available, and can play an important role in investigating clam shrimp carapace morphology which could be common language to integrate fossil and modern taxonomy.

Transferring the freshwater dinoflagellate Peridinium wisconsinense (Dinophyceae) to the family Thoracosphaeraceae, with the description of Fusiperidinium gen. nov.

SUMMARYDistinctive spindle‐shaped thecae first described by Samuel Eddy in 1930 and assigned to the genus Peridinium Ehrenberg are commonly reported from freshwater environments in eastern North America. We demonstrate that thecae incubated from cysts of Peridinium wisconsinense Eddy have six cingular plates and a protuberant apical pore complex characteristic of the family Thoracosphaeraceae Schiller 1930 emend. Tangen in Tangen et al. 1982. Small subunit ribosomal DNA (SSU rDNA) and internal transcribed spacer (ITS) sequences confirm the close genetic similarity with Chimonodinium lomnickii (Wołoszyńska) Craveiro, Calado, Daugbjerg, Gert Hansen & Moestrup and with species recently reassigned to the genus Apocalathium Craveiro, Daugbjerg, Moestrup & Calado that was inferred from previously published LSU rDNA analysis of cysts of P. wisconsinense. Despite sharing identical tabulation with the thoracosphaeracean genera Chimonodinium Craveiro, Calado, Daugbjerg, Gert Hansen & Moestrup and Apocalathium, substantial morphological differences in the morphology of both the thecate and cyst stages of P. wisconsinense led us to reassign this species to the genus Fusiperidinium gen. nov. The phylogenetic position of Fusiperidinium wisconsinense comb. nov., inferred from concatenated data of SSU and LSU sequences, suggests that it evolved from the brackish Scrippsiella lineage, independently of the transition that produced the family Peridiniaceae. Cysts described as Geiselodinium tyonekensis Engelhardt from nonmarine strata from Alaska are apparently identical to the resistant cysts produced by F. wisconsinense. The palynologically‐constrained late Middle Miocene age for the Tyonek Formation provides a minimum age of 11.6 Ma for the evolution of this lineage, coinciding with a rapid glacioeustatic decline in sea level. Our findings also call into question the inclusion of the family Thoracosphaeraceae within the order Peridiniales Haeckel.

The Jurassic–Cretaceous boundary interval in non-marine strata of northwest Europe – New light on an old problem

The non-marine Purbeck- and Wealden-type sediments of latest Jurassic (Tithonian) and earliest Cretaceous (Berriasian) age in northern Germany were deposited in a restricted intercontinental basin. They mark an interval of strong faunal and floral provincialism which makes correlation of the non-marine strata across northwest Europe difficult. The position of the Jurassic–Cretaceous boundary has therefore been debated for decades. Our integrated stratigraphy of four sections in northern Germany, based on palynology (spores, pollen, dinoflagellate cysts) and ostracods, provides new evidence for a precise correlation with contemporaneous strata of other non-marine basins in northwest Europe. Correlation with the marine Boreal Realm and the Tethys is achieved via the Purbeck type section in England. A stratigraphic subdivision of the non-marine Berriasian succession in Germany is possible by using seven short-lived marine flooding events, which are documented by ceratioid dinoflagellate cysts and foraminifera. Our data suggest that a first major transgression took place close to the base of the Boreal Surites stenomphalus ammonite Zone. This level corresponds to a contemporaneous flooding event in southern England (Scallop Beds, Purbeck Group) and in southern Sweden (Annero Formation), thereby providing an excellent marker horizon for interbasinal correlation.