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Simple Summary: The way of life and biology of extinct animals can be inferred from growth marks and microstructures in their fossil bones. Hyposaurus is a genus representative of dyrosaurids, a group of crocodile-like animals that survived the extinction event that killed the dinosaurs but nonetheless has long become extinct. The current study focuses on bone sections from a single individual, extracted from the optimal location in the best bones for such studies. It complements and corrects previous works based on less optimal material, and concludes that the genus was a marine ambush predator rather than a fast-swimming pursuit predator, that the males of the genus grew larger than the females, and that the individual studied was a fully mature 17–18-year-old female. The paleohistology of dyrosaurids is known from a small sample, despite being common fossils and representing a rare lineage of crocodylomorphs that survived the Cretaceous–Paleogene extinction. Their lifestyle has been inferred only from sections of the snout, vertebrae, partial femur, and tibia. To improve this, we conducted a skeletochronological and paleohistological study of midshaft cross-sections of both femora and humeri of a nearly complete Hyposaurus rogersii skeleton. We found lamellar-zonal bone that underwent remodeling, evidenced by resorption cavities and abundant secondary osteons within the primary periosteal cortex. The osteons, mostly longitudinally oriented and arranged in circular rows, often anastomose radially along a linear path, resembling radial rows. The medullary cavity is completely open, lacking trabeculae: endosteal deposition is limited to thin lamellae surrounding the cavity. Analysis of cyclical growth marks and the presence of an external fundamental system indicate the specimen was a fully mature adult 17–18 years of age. Comparison of the skeleton to others suggests sexual dimorphism and that it was female. The open medullary cavity, and no evidence for pachyosteosclerosis, osteosclerosis, osteoporosis, or pachyostosis indicate H. rogersii was not a deep diver or a fast swimmer in the open ocean but a near-shore marine ambush predator. [ABSTRACT FROM AUTHOR]

The Qolqoleh gold deposit is located in the northwestern part of the Sanandai-Sirjan Zone, northwest of Iran. Gold mineralization in the Qolqoleh deposit is almost entirely confined to a series of steeply dipping ductile–brittle shear zones generated during Late Cretaceous–Tertiary continental collision between the Afro-Arabian and the Iranian microcontinent. The host rocks are Mesozoic volcano-sedimentary sequences consisting of felsic to mafic metavolcanics, which are metamorphosed to greenschist facies, sericite and chlorite schists. The gold orebodies were found within strong ductile deformation to late brittle deformation. Ore-controlling structure is NE–SW-trending oblique thrust with vergence toward south ductile–brittle shear zone. The highly strained host rocks show a combination of mylonitic and cataclastic microstructures, including crystal–plastic deformation and grain size reduction by recrystalization of quartz and mica. The gold orebodies are composed of Au-bearing highly deformed and altered mylonitic host rocks and cross-cutting Au- and sulfide-bearing quartz veins. Approximately half of the mineralization is in the form of dissemination in the mylonite and the remainder was clearly emplaced as a result of brittle deformation in quartz–sulfide microfractures, microveins and veins. Only low volumes of gold concentration was introduced during ductile deformation, whereas, during the evident brittle deformation phase, competence contrasts allowed fracturing to focus on the quartz–sericite domain boundaries of the mylonitic foliation, thus permitting the introduction of auriferous fluid to create disseminated and cross-cutting Au-quartz veins. According to mineral assemblages and alteration intensity, hydrothermal alteration could be divided into three zones: silicification and sulfidation zone (major ore body); sericite and carbonate alteration zone; and sericite–chlorite alteration zone that may be taken to imply wall-rock interaction with near neutral fluids (pH 5–6). Silicified and sulfide alteration zone is observed in the inner parts of alteration zones. High gold grades belong to silicified highly deformed mylonitic and ultramylonitic domains and silicified sulfide-bearing microveins. Based on paragenetic relationships, three main stages of mineralization are recognized in the Qolqoleh gold deposit. Stage I encompasses deposition of large volumes of milky quartz and pyrite. Stage II includes gray and buck quartz, pyrite and minor calcite, sphalerite, subordinate chalcopyrite and gold ores. Stage III consists of comb quartz and calcite, magnetite, sphalerite, chalcopyrite, arsenopyrite, pyrrhotite and gold ores. Studies on regional geology, ore geology and ore-forming stages have proved that the Qolqoleh deposit was formed in the compression–extension stage during the Late Cretaceous–Tertiary continental collision in a ductile–brittle shear zone, and is characterized by orogenic gold deposits. [ABSTRACT FROM AUTHOR]

In this study, using neutron activation analysis with multi-parameter coincidence method which was developed at Japan Atomic Energy Agency (JAEA), a non-destructive, ultra-high sensitive multi-elemental determination has been realized. The multi-parameter coincidence method is carried out with an array of 19 germanium detectors, GEMINI-II. Using this system, very weak γ-rays emitted from trace amounts of elements can be detected. The iridium concentration has been determined by means of neutron activation analysis with multi-parameter coincidence method for Cuban sediment samples across the K/T boundary strata. [ABSTRACT FROM AUTHOR]

Did the end-Cretaceous mass extinction event, by eliminating non-avian dinosaurs and most of the existing fauna, trigger the evolutionary radiation of present-day mammals? Here we construct, date and analyse a species-level phylogeny of nearly all extant Mammalia to bring a new perspective to this question. Our analyses of how extant lineages accumulated through time show that net per-lineage diversification rates barely changed across the Cretaceous/Tertiary boundary. Instead, these rates spiked significantly with the origins of the currently recognized placental superorders and orders approximately 93 million years ago, before falling and remaining low until accelerating again throughout the Eocene and Oligocene epochs. Our results show that the phylogenetic ‘fuses’ leading to the explosion of extant placental orders are not only very much longer than suspected previously, but also challenge the hypothesis that the end-Cretaceous mass extinction event had a major, direct influence on the diversification of today’s mammals. [ABSTRACT FROM AUTHOR]

A new species of Araripesuchus present in the Maevarano Formation of Madagascar is described. The taxon is known from at least five individuals, including a nearly complete animal, three partial skulls and associated post-cranial remains, as well as disarticulated post-cranial elements. This large sample, coupled with CT-scans, allows a detailed description of its morphology. The new form shares a number of derived characters with Araripesuchus gomesii and Araripesuchus patagonicus , but is distinguished from them by the presence of four autapomorphies. Additionally, the new form lacks a number of derived features present in A. gomesii and A. patagonicus . Phylogenetic relationships of Araripesuchus are evaluated using a parsimony analysis including 29 mesoeucrocodylian taxa. In all of the most parsimonious trees the new taxon is recovered as sister group to A. gomesii + A. patagonicus . Araripesuchus is diagnosed by five unambiguous synapomorphies and forms a clade with the Malagasy crocodyliform Mahajangasuchus insignis and peirosaurids. This group is depicted as more closely related to neosuchians than to notosuchians. When Araripesuchus wegeneri is included in the analysis, it is recovered as a member of the Araripesuchus clade. Although, its position in the clade is unresolved and character support is weak, this finding supports A. wegeneri as a valid species of Araripesuchus . [ABSTRACT FROM AUTHOR]

Most geologists asked to comment on the geology of Denmark would probably think of Cretaceous Chalk and Pleistocene glacial deposits. Today, many will perhaps be familiar with the Cretaceous–Tertiary boundary clay at Stevns Klint, which has played a prominent role in the discussions regarding the mass extinction event at this time (the ever popular ‘end of the dinosaurs’). Few would perhaps think of volcanic or tectonic phenomena, although, in fact, outstanding localities for these processes are to be found here, documenting a time when dense volcanic ash clouds drifted over north-west Europe. [ABSTRACT FROM AUTHOR]

The genus Dreissena includes two widespread and aggressive aquatic invaders, the zebra mussel, Dreissena polymorpha, and the quagga mussel, Dreissena bugensis. This genus evolved in the Ponto-Caspian Sea basin, characterized by dynamic instability over multiple timescales and a unique evolutionary environment that may predispose to invasiveness. The objectives of this study were to gain insights into the demographic history of Dreissena species in their endemic range, to reconstruct intraspecific phylogeographic relationships among populations, and to clarify systematics of the genus, using DNA sequences from the mitochondrial cytochrome oxidase I (COI) gene. We found four deeply diverged clades within this genus, with a basal split that approximately coincided with the Cretaceous–Tertiary boundary. Divergence events within the four base clades were much more recent, corresponding to geographically disjunct sets of populations, which might represent species complexes. Across all taxa, populations of Dreissena shared a common pattern of genetic signatures indicating historical population bottlenecks and expansions. Haplotype diversity was relatively low in Ponto-Caspian drainages relative to more stable tectonic lakes in Greece, Macedonia, and Turkey. The phylogeographic and demographic patterns in the endemic range of Dreissena might have resulted from vicariance events, habitat instability, and the high fecundity and passive dispersal of these organisms. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Botany is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The pattern, timing and extent of the evolutionary radiation of anatomically modern birds (Neornithes) remains contentious: dramatically different timescales for this major event in vertebrate evolution have been recovered by the ‘clock-like’ modelling of molecular sequence data and from evidence extracted from the known fossil record. Because current synthesis would lead us to believe that fossil and nonfossil evidence conflict with regard to the neornithine timescale, especially at its base, it is high time that available data are reconciled to determine more exactly the evolutionary radiation of modern birds. In this review we highlight current understanding of the early fossil history of Neornithes in conjunction with available phylogenetic resolution for the major extant clades, as well as recent advancements in genetic methods that have constrained time estimates for major evolutionary divergences. Although the use of molecular approaches for timing the radiation of Neornithes is emphasized, the tenet of this review remains the fossil record of the major neornithine subdivisions and better-preserved taxa. Fossils allowing clear phylogenetic constraint of taxa are central to future work in the production of accurate molecular calibrations of the neornithine evolutionary timescale. © 2004 The Linnean Society of London, Zoological Journal of the Linnean Society, 2004, 141, 153–177. [ABSTRACT FROM AUTHOR]

The nature of the molecular and fossil record and their limitations must be ascertained in order to gain the most precise and accurate evolutionary timescale using genetic information. Yet the majority of such timescales are based on point estimates using fossils or the molecular clock. Here we document from the primary literature minimum and maximum fossil age estimates of the divergence of whales from artiodactyls, a commonly used anchor point for calibrating both mitogenomic and nucleogenomic placental timescales. We applied these reestimates to the most recently established placental timescale based on mitochondrial rRNA and several nuclear loci, and present an attempt to account for both genetic and fossil uncertainty. Our results indicate that disregard for fossil calibration error may inflate the power of the molecular clock -when testing the time of ordinal diversification in context with the K-T boundary. However, the early history of placentals, including their superordinal diversification, remained in the Cretaceous despite a conservative approach. Our conclusions need corroboration across other frequently used fossil anchor points, but also with more genetic partitions on the linear relationship between molecular substitutions and geologic time. [ABSTRACT FROM AUTHOR]

The depositional and diagenetic history of Cretaceous–Tertiary (KT) impact ejecta deposited 360 km from the Chicxulub crater, at Albion Island, Belize, has been investigated using integrated cathodoluminescence and isotopic analyses. A quarry exposes 26 m of Upper Cretaceous Barton Creek Formation dolomitized marine limestone overlain by 16 m of dolomitized Albion Formation impact ejecta. The Albion Formation consists of a lower fine-grained ≈1-m-thick spheroid bed and an upper 15-m-thick coarse conglomeratic diamictite bed. A 14-event paragenetic sequence has been documented and used as a temporal framework to interpret chemostratigraphic trends in bulk rock δ18 O, δ13 C and 87 Sr/86 Sr. The uppermost surface of the Barton Creek Formation was subaerially exposed before the KT impact, as indicated by a brecciated palaeosol that caps upsection decreases in δ13 C and δ18 O. Small 1-cm-diameter spheroids in the spheroid bed exhibit vermicular crystalline textures but lack the concentric zonations common to accretionary lapilli. These spheroids are hypothesized originally to have been impact glass or reactive Ca and Mg oxide dusts that adhered to water vapour particles condensing from the cooling impact vapour cloud. The spheroids were dolomitized soon after deposition. The earliest dolomitization in the matrix sediments of the Albion Formation was also post-depositional, replacing clays formed by devitrification of impact glass. Dolomite and clay 87 Sr/86 Sr exhibit a distinct symmetrical distribution in the spheroid bed ranging from 0·707745 to 0·707872. Although unproven, this may represent primary changes in the chemical composition of the impact glass. The limestone clasts in the diamictite bed were dolomitized before the KT impact and exhibit upsection decreases in bulk rock 87 Sr/86 Sr. This suggests that... [ABSTRACT FROM AUTHOR]

Presents a study that determined the organic geochemistry of the Cenomanian-Turonian anoxic event in southern Tibet, China. Analysis of the mid-Cretaceous samples; Use of direct combustion; Total organic carbon and its source.

Focuses on the debate on mass extinctions (ME) with regard to the Cretaceous-Tertiary (K/T) boundary, which has been one of the central themes of the Snowbird conference in Vienna in July 2000. ME-related events discussed in the conference; Issues to be resolved regarding the Permian-Triassic boundary; Destructive effects of the K/T event on the earth's ecosystems.

Presents a graphical technique called stratigraphic plane analysis to explore the short-term biotic events on Seymour Island, Antarctic Peninsula. Application of the method; Divergence of the Cretaceous Tertiary boundary; Evaluation of late Maastrichtian ammonite ranges; Range of cephalopod fauna.

In the La Sierrita area of Nuevo Leon, Mexico, three spherule layers are present and separated from the overlying siliciclastic deposits by up to 6 m of pelagic marls. The marls are of latest Maastrichtian age (Plummerita hantkeninoides (CF1) Zone, Micula prinsii Zone) and deposited under normal pelagic conditions with no significant evidence of reworking or slumping. Original deposition of the spherule layers occurred during the last 300 ka of the Maastrichtian and well prior to the Cretaceous-Tertiary (K–T) boundary event. Thus, if the spherules in northeastern Mexico provide critical evidence of an impact at Chicxulub, this impact predates the K–T boundary.Dans la région de La Sierrita de Nuevo Leon, au Mexique, on retrouve trois couches de sphérules et jusqu'à 6 m de marnes pélagiques les séparent des dépôts silicoclastiques sus-jacents. Les marnes sont du Maastrichtien terminal (zone Plummerita hantkeninoides (CF1), zone Micula prinsii) et elles ont été déposées sous des conditions pélagiques normales sans évidence significative de reprise ni de glissement. La déposition originale des couches de sphérules a eu lieu au cours des derniers 300 ka du Maastrichtien et bien avant l'événement limite K–T. Ainsi, si les sphérules au nord-est du Mexique fournissent une évidence critique pour un impact à Chicxulub, cet impact a eu lieu avant la limite K–T.[Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]

Abstract Sandstones from the Upper Cretaceous to Eocene succession of Central Palawan are rich in quartz grains and acidic volcanic rock fragments. Potassium feldspar grains and granitic rock fragments are commonly observed. The moderate to high SiO2 and low FeO plus MgO contents of the sandstones support the proposal that clasts were derived from a continental source region. Southern China (Kwangtung and Fukien regions) is inferred to be the source area of the sandstones. The sedimentary facies of the Upper Cretaceous to Eocene succession consist of turbidite and sandstones, suggesting that they were deposited in the deep sea portions of submarine-fans and basin plains situated along a continental margin. These features indicate that the Upper Cretaceous to Eocene succession of the Central Palawan were derived and drifted from the southern margin of China. The tectonic history related to the formation of Palawan Island is also discussed. [ABSTRACT FROM AUTHOR]

Presents a study which analyzed the patterns of change in seed size, fruit size and dispersal systems during angiosperm evolution from the Early Cretaceous to the Late Tertiary. Materials and methods used; Results and discussion.

The article discusses a study on alienation of volcanism in Deccan Traps, India with extinction of dinosaurs conducted by Blair Schoene and others, released by the Princeton University. Topics discussed include evidences of massive volcanic explosions released climate-altering gases into the atmosphere before and during the extinction of Earth's nonavian dinosaurs; role of Deccan Traps in the Cretaceous-Paleogene period extinction; and view of coauthor of the study Gerta Keller.

The tectono-sedimentary evolution of the Cenozoic basins in the Eastern External Betic Zone (SE Spain) was reviewed by Martín-Martín et al. (2020) [[7]]. 10.3390/geosciences10100394 8 Guerrera F., Martín-Martín M., Tramontana M. Evolutionary Models of the Cenozoic Basins of Central-Western Mediterranean Area: A Review of Methodological Approaches. 10.3390/geosciences11010023 7 Martín-Martín M., Guerrera F., Tramontana M. Tectono-Sedimentary Evolution of the Cenozoic Basins in the Eastern External Betic Zone (SE Spain). [Extracted from the article]

The article reports that Professor Lingham Soliar of the Paleontological Institute, Moscow, confirms of strong evidence for concluding that a group of marine reptiles, the gigantic mosasaurs, were in fact thriving just before they became suddenly extinct, thus lending strong support to the catastrophic extinction scenario. Many possible causes have been advanced to account for the K-T extinction. Because iridium is rare on Earth but common in meteorites, they postulated that the K-T mass extinction was the result of a giant-meteor or asteroid impact on Earth.

Solid bodies of upper-mantle peridotite, emplaced in the Betic-Rif chains of SW Spain and North Morocco, show a variety of structures developed under different metamorphic conditions. These structures and related metamorphism reflect tectonic processes in the West Mediterranean mantle during orogeny in the Betic-Rif realm. The largest of the peridotites, the Ronda massif, has preserved three structural domains which are spatially associated with metamorphic domains previously defined by Obata (Journal of Petrology, 21,533–572, 1980). These structural domains include: (1) porphyroclastic spinel peridotites (spinel tectonites) and mylonitic garnet-spinel peridotites (garnet-spinel mylonites), developed during progressive strain localization at ambient conditions changing from the Ariégite subfacies to garnet peridotite facies; (2) seemingly undeformed granular peridotites, developed during a phase of extensive recrystallization affecting the spinel tectonites and garnet-spinel mylonites at Seiland subfacies conditions, and separated from the spinel tectonites by a well-preserved recrystallization front which forms a marked structural, metamorphic and possibly geochemical boundary probably unique to orogenic peridotites; (3) porphyroclastic plagioclase peridotites (plagioclase tectonites) developed at the expense of the granular peridotites during progressive shear localization allied to ductile emplacement of the Ronda massif into the crust.Our structural and microstructural data from the Ronda massif allow us to assess the relative ages of the different metamorphic facies seen in the West Mediterranean peridotites. In order of decreasing relative age, these are: Ariégite-subfacies, garnet peridotite facies, Seiland subfacies and plagioclase peridotite facies. In addition, the associated microstructures provide some insight into the microphysical conditions controlling the development of the different structures and, as a result, the structural and chemical heterogeneity of the West Mediterranean peridotites. [ABSTRACT FROM AUTHOR]

Argues that the species changes at the Cretaceous-Tertiary (K/T) boundary were neither sudden nor catastrophic. Suggestion that the changes were most likely caused by a regression of sea level that led to a decrease in primary production; Evidence that extinctions were compressed into a small time span; Determination of the proportion of the Earth's species that became extinct due to K/T boundary events.

Small-scale hummocky cross-stratification occurs in Upper Cretaceous calciclastic turbidites exposed in the western Basque Pyrenees: facies association and microfossil assemblages indicate slope to base-of-slope (bathyal) depositional environments. It is developed in the fine-grained portion of beds and displays spacings mostly between 0.2 and 0.7 m. The beds fine upward with no sharp grain size breaks or mud partings, suggesting that deposition occurred during a single flow event. Hummocky intervals are 0.1-0.8 m thick and consistently grade laterally and vertically into flat, planar laminations of Bouma B divisions suggesting that deposition occurred under upper-flow-regime conditions. They have wave-like geometries with laminae continuous across `crests' and `troughs' and display a ratio of `wavelength' to estimated underflow thickness of 11.3-12.8. Combining the above observations and inferences, these examples of small-scale hummocky cross-stratification are interpreted as a form of antidune stratification generated by standing waves along the interface of a thinner, denser underflow (main body/tail of the turbidity current) and an overlying thicker, low-density layer. This occurrence is further evidence that small-scale hummocky cross-stratification is multigenetic and therefore not indicative of a particular flow condition or depositional environment. [ABSTRACT FROM AUTHOR]

Shell aragonite from ammonites collected in the Upper Cretaceous of West Greenland was investigated by means of macroscopic/microscopic visual evaluation, analyses of calcite/aragonite ratios, carbon and oxygen isotopic compositions and Sr and Mg concentrations of shell carbonate and of amino acid compositions of organic matrices. The results are: (1) Material visually classified as welt preserved may have suffered diagenetic modifications of mineralogical and chemical composition. (2) Of the chemical and mineralogical parameters studied, amino acid composition, calcite/aragonite ratios and magnesium concentrations were found to be most sensitive to post-depositional modifications, while oxygen isotope composition and strontium concentrations showed detectable diagenetic modifications only after more pronounced alterations. (3) Based on the Mg/Ca ratios and calcite concentrations of the shell aragonite, a diagenetic classification has been proposed grouping the material into well preserved, moderately preserved and poorly preserved. (4) The chemical and mineralogical composition of the best preserved material suggests that the Upper Cretaceous ammonites had a shell composition similar to that of modern Nautilus and other aragonite-shelled molluscs. [ABSTRACT FROM AUTHOR]

Offers the results of an investigation of the petrology and structure of the Skymo complex and adjacent terranes in a segment of the Late Cretaceous-early Tertiary Ross Lake fault zone (RLFZ), a major orogen-parallel shear zone in the Cordillera of western North America. Geologic setting; Overview of Skymo Lake region; Petrology; Thermoblastic results.

The Upper Maastrichtian fluvial Hell Creek Formation of the Fort Peck Lake area, Montana (and regional equivalents) is notable for its vertebrate fossils and for the K-Pg mass extinction at or near its upper contact. Despite intense study, internal stratigraphy of the Hell Creek Formation is still poorly constrained, hindering study. This work reviews the stratigraphy of the Hell Creek Formation, as currently understood, and proposes important revisions to the recently proposed type section, particularly concerning complexity of the Hell Creek Formation basal contact. This work also subdivides the Montanan Hell Creek Formation into four 4th order depositional sequences, superimposed over a 3rd order marine transgression. Sequence boundaries are defined by four, laterally continuous disconformities formed by pauses in the creation of accommodation space, marked by overlying amalgamated channel complexes, or less commonly, correlative interfluve paleosols. Cyclicity in Montana may be correlative with similar 4th order cyclicity and marine influence documented in North and South Dakota, Alberta, and Saskatchewan. Magnetostratigraphy and new biostratigraphic data support correlation of the upper Montanan sequence with the North Dakotan Cantapeta tongue (and overlying fines) and Canadian Scollard and Frenchman Formations. [ABSTRACT FROM AUTHOR]

Four main unconformities (1–4) were recognized in the sedimentary record of the Cenozoic basins of the eastern External Betic Zone (SE, Spain). They are located at different stratigraphic levels, as follows: (1) Cretaceous-Paleogene boundary, even if this unconformity was also recorded at the early Paleocene (Murcia sector) and early Eocene (Alicante sector), (2) Eocene-Oligocene boundary, quite synchronous, in the whole considered area, (3) early Burdigalian, quite synchronous (recognized in the Murcia sector) and (4) Middle Tortonian (recognized in Murcia and Alicante sectors). These unconformities correspond to stratigraphic gaps of different temporal extensions and with different controls (tectonic or eustatic), which allowed recognizing minor sedimentary cycles in the Paleocene–Miocene time span. The Cenozoic marine sedimentation started over the oldest unconformity (i.e., the principal one), above the Mesozoic marine deposits. Paleocene-Eocene sedimentation shows numerous tectofacies (such as: turbidites, slumps, olistostromes, mega-olistostromes and pillow-beds) interpreted as related to an early, blind and deep-seated tectonic activity, acting in the more internal subdomains of the External Betic Zone as a result of the geodynamic processes related to the evolution of the westernmost branch of the Tethys. The second unconformity resulted from an Oligocene to Aquitanian sedimentary evolution in the Murcia Sector from marine realms to continental environments. This last time interval is characterized as the previous one by a gentle tectonic activity. On the other hand, the Miocene sedimentation was totally controlled by the development of superficial thrusts and/or strike-slip faults zones, both related to the regional geodynamic evolutionary framework linked to the Mediterranean opening. These strike-slip faults zones created subsidence areas (pull-apart basin-type) and affected the sedimentation lying above the third unconformity. By contrast, the subsidence areas were bounded by structural highs affected by thrusts and folds. After the third unconformity, the Burdigalian-Serravallian sedimentation occurred mainly in shallow- to deep-water marine environments (Tap Fm). During the Late Miocene, after the fourth unconformity, the activation of the strike-slip faults zones caused a shallow marine environment sedimentation in the Murcia sector and a continental (lacustrine and fluvial) deposition in the Alicante sector represented the latter, resulting in alluvial fan deposits. Furthermore, the location of these fans changed over time according to the activation of faults responsible for the tectonic rising of Triassic salt deposits, which fed the fan themselves. [ABSTRACT FROM AUTHOR]

Nearly all lineages of birds host parasitic feather lice. Based on recent phylogenomic studies, the three major lineages of modern birds diverged from each other before the Cretaceous-Paleogene (K-Pg) mass extinction event. In contrast, studies of the phylogeny of feather lice on birds, indicate that these parasites diversified largely after this event. However, these studies were unable to reconstruct the ancestral avian host lineage for feather lice. Here we use genome sequences of a broad diversity of lice to reconstruct a phylogeny based on 1,075 genes. By comparing this louse evolutionary tree to the avian host tree, we show that feather lice began diversifying on the common ancestor of waterfowl and landfowl, then radiated onto other avian lineages by extensive host-switching. Dating analyses and cophylogenetic comparisons revealed that two of three lineages of birds that diverged before the K-Pg boundary acquired their feather lice after this event via host-switching. Robert de Moya et al. use comparative genomics of avian lice to reconstruct the phylogeny of these parasites. They show that feather lice diversified on the common ancestor of waterfowl and landfowl, and then radiated onto other avian lineages through host-switching. [ABSTRACT FROM AUTHOR]

The article reflects on the Earth-asteroid collision incident which occurred during the ancient period at the Cretaceous-Tertiary boundary. It considers the legacy of the event impressive, because its changes the status of Earth under the dominance of dinosaurs. It also notes that the catastrophe influenced the approaches used by scientists in dealing various Earth sciences. Meanwhile, it claims that the ability of diverse sciences to explain past scientific events deserves praise and emulation.

The median antiformal axis of the Otago Schist, New Zealand, is marked by a zone of relatively high-grade (up to garnet–biotite–albite) greenschist facies rocks. 40 Ar/39 Ar geochronology has been carried out in conjunction with structural analysis in regions distant from the effects of the Alpine Fault to determine the origin of this metamorphic welt. We have determined that the metamorphic welt is bounded on its northern and southern sides by multistage ductile shear zone(s) marked by intensely developed fabrics, and/or low-angle normal faults. These structures extend over a strike length of >∼200 km and on the southern side of the metamorphic welt they mark the boundary between the Caples and the Torlesse terranes. The oldest such shear zone formed between 122 and 118 Ma. The metamorphic welt was exhumed beneath low-angle normal faults and ductile shear zones that formed from 112 to 109 Ma. The shear zones form the carapace to elongate domal culminations in the central Otago Schist. These geomorphological features are Cretaceous metamorphic core complexes dissected by younger Quaternary faults. Exhumation of the shear zones occurred shortly before volcanogenic sediments began to deposit on a Cretaceous unconformity. We propose that both the Cretaceous unconformity and the underlying ductile shear zones and low-angle faults are a direct result of extensional tectonism. The ductile shear zones display both ‘cross-belt’ and ‘belt-parallel’ stretching lineations. Cross-belt stretching may have been caused by rollback of the subducting Pacific slab. Belt parallel extension is interpreted to have taken place during extension associated with rifting between Australia and Antarctica, prior to breakup. [ABSTRACT FROM AUTHOR]

A 2 m-thick diamictite occurs near the base of the Cretaceous Eromanga Basin succession at Trinity Well, at the northern extremity of the Flinders Ranges in South Australia. The diamictite consists of a matrix of silt- and clay-size particles and a framework of sand and coarser materials up to small boulder size. Scanning electron microscope study reveals the presence of numerous quartz grains displaying extreme angularity and surface textures attributed to glacial crushing. Sandy sediments considered as fluvioglacial in origin and a locally developed facies displaying flow structures attributed to solifluction processes constitute the basal 3–5 m of the sequence. In places these directly underlie the diamictite and rest with angularity on Neoproterozoic Adelaidean strata. Conformably above the diamictite at the type locality ‘Recorder Hill’ is a sequence approximately 15 m thick of fine sand and silt units containing lonestones up to ∼70 cm diameter and hummocky cross-stratification. These sediments have been assigned to the Cadna-owie Formation and are dated on palynology as Berriasian to Valanginian. The occurrence of diamictite containing glacially affected quartz grains contributes to our interpretation that the southern margin of the Eromanga Basin, and at least the adjacent part of the northern Flinders Ranges, were affected by glaciation in the Early Cretaceous. The associated dropstone and solifluction facies and nearby glendonite pseudomorphs after ikaite are further evidence of at least intermittent cold climates at this time. [ABSTRACT FROM AUTHOR]

This study reports elasmobranch remains from two fossil‐rich horizons in the earliest Danian Olching Formation at Waidach, Austria. These outer neritic assemblages complement previous fine‐scale bulk‐sampling of latest Maastrichtian horizons at Waidach and document a regional elasmobranch faunal turnover across the Cretaceous–Palaeogene (K–Pg) boundary. The Danian assemblages show homogeneity in species richness and are dominated by squaliforms. The fauna comprises 16 species belonging to 12 genera including several new taxa (Centrodeania rugosa gen. et sp. nov., Centrodeania annae gen. et sp. nov., Incognitorapax fernsebneri gen. et sp. nov., Scyliorhinus alaformis sp. nov.). Comparison with latest Maastrichtian assemblages from Waidach revealed a marked faunal turnover across the K–Pg boundary associated with an increase in species richness and shift in abundance from Squaliformes to Carcharhiniformes. This is associated with marked environmental changes from a deep marine, dysoxic setting in the Maastrichtian to a more oxygenated, shallower environment in the earliest Danian. The turnover was driven by environmentally induced regional changes in species geographic ranges. High diversity in the Danian fauna suggests that the habitability of the corresponding palaeoenvironment was preserved or recovered immediately after the K–Pg event. Comparison with other elasmobranch assemblages across the K–Pg boundary highlights a strong control of local palaeoenvironmental settings over the timing and magnitude of the turnover. Our study emphasizes the importance of successive sampling to disentangle local from general patterns of faunal turnover during the K–Pg event and to better assess the consequences of this extinction event over elasmobranch diversity. [ABSTRACT FROM AUTHOR]