Stratigraphic Origin Research Articles

Performance of Different ANNs in Microtremor H/V Peak Classification

Abstract The microtremor horizontal-to-vertical (H/V) technique is extensively used to both assess the seismic amplification potential of soils and, in combination with other surface wave-based techniques, to reconstruct the near-surface seismic stratigraphy. The H/V peak frequencies are traditionally interpreted in terms of soil resonances, and, in this case, they are assigned a “stratigraphic origin.” However, not all H/V peaks mark subsoil resonances, and some of them have “anthropic” or “artefactual” origin. Recognizing the nature of H/V peaks should be mandatory before any stratigraphic interpretation. Nonetheless, this problem is not given the attention it deserves. Because this classification is not easy to achieve using standard statistical techniques, we decided to train two supervised neural networks: a traditional artificial neural network using a set of input values extracted from the individual (horizontal and vertical) microtremor spectra and a convolutional neural network working on images of the microtremor spectra. The nets were trained on an Italian dataset and tested on a U.S. dataset, collected by different operators and with different instruments. Both the nets achieved a classification accuracy of ∼90%; however, the convolutional one showed a greater generalization capability compared to the traditional one. Such machine learning algorithms can be useful tools to discriminate the origin of H/V peaks, complementing the traditional SESAME guidelines, which do not go into much detail on this topic.

Source rock potential and spatial distribution of the stratigraphic formations in the central Mediterranean Ridge: Evidence from mud volcanic deposits and 2D seismic data

Due to the lack of deep wells in the broader region, the mud volcanic deposits (mud breccia) are the only source of direct information for the deep stratigraphic units of the Mediterranean Ridge (MR), in the eastern Mediterranean. The study of this material, combined with the available seismic data, can improve the geological understanding of this frontier exploration area.In this paper, biostratigraphic and geochemical studies are performed on mud breccia deposits from five Mud Volcanoes (MVs) in the central MR, aiming to define the sediments’ stratigraphic origin and assess the source rock potential of the individual formations. In addition, regional seismic data is used to reveal the spatial distribution of the major lithostratigraphic formations in the subsurface.Results indicate an Eocene-Miocene origin for the mud breccia of Gelendzhik, Nice, Moscow and Dublin MVs, whereas a Paleocene (?) and Cretaceous origin is suggested for the Toronto MV deposits. Most clasts represent hemipelagic mudstones/marlstones. Regarding the source rock potential of the area, it is considered that: (a) nine clasts of Miocene, Eocene and undetermined age, reflect the presence of immature and early mature, gas-prone source rocks of poor to moderate potential; (b) a small clast discovered in the matrix of Dublin MV originates from an excellent quality oil-prone source rock; and (c) the discovered solid hydrocarbons and oil droplets point to an active petroleum system in the region.Seismic interpretation defines the spatial distribution of the Post-Evaporite, Evaporite and Pre-Evaporite formations. The burial depth of the Pre-Evaporite formation (source layers of MV deposits) significantly varies from 20 to 4970 m inside the study area and is largely dependent on Evaporite thickness.

Geophysical Subsoil Characterization and Modeling Using Cluster Analysis for Seismic Microzonation Purposes

In the municipality of Enna, 80 HVSR measurements were performed, and some of these were combined with MASW seismic measurements, which made it possible to constrain the data inversion and obtain significant shear wave velocity models. A reconstruction of the depth of the seismic bedrock was performed for the whole territory, showing different depths for the higher and lower areas, as evidenced also by the Vseq parameter map. The frequency peaks identified in the H/V curve were analyzed through a cluster analysis algorithm to evaluate similarities that allow these peaks to be divided according to their stratigraphic origin. A non-hierarchical analysis algorithm modified in such a way as to avoid any a priori choice that could influence the partition has been used. The cluster analysis made it possible to divide the frequency peaks into five groupings, each of which was then associated with a seismic discontinuity, according to the geological contacts expected in the subsoil. Finally, the inversion of the data made it possible to reconstruct the geometries of these geological contact surfaces and to reconstruct a 3D model of the subsoil, which agrees well with the surface geology of the area.

In-situ Aptychus in Cleviceras from the Mulgrave Shale Member of the Whitby Mudstone Formation (Jurassic) of Port Mulgrave, Whitby

A specimen of the ammonoid Cleviceras (Hildoceratidae), collected at Port Mulgrave, near Whitby, North Yorkshire, shows an in-situ aptychus in the body chamber. The precise stratigraphic origin of the specimen is unknown, but the lithology and generic identity are compatible with derivation from the Mulgrave Shale Member of the Whitby Mudstone Formation. The specimen is the first in-situ jaw apparatus to be reported for this genus from Britain. A second loose specimen, a Harpoceras sp. with in-situ aptychus was found and photographed at Deepgrove Wyke, but was too friable to be collected. Both specimens reinforce previous observations that the aptychus form type Cornaptychus is characteristic of the ammonite family Hildoceratidae.

Preliminarily report on rare earth element taphonomy of a Miocene mixed age fossil vertebrate assemblage (Pécs-Danitzpuszta, Mecsek Mts., Hungary): uptake mechanism and possible separation of palaeocommunities

ABSTRACT The sand pit of Pécs-Danitzpuszta is one of the most important mixed Neogene vertebrate localities in Hungary, with older Miocene (Langhian – Serravallian) terrestrial and marine animal remains re-deposited into the upper Miocene (Tortonian) Lake Pannon sediments. Due to the mixed status of the Pécs-Danitzpuszta vertebrate assemblages, limited information is available about the former depositional environment and age of these fossils. However, the rare earth element (REE) composition of the fossil apatite can help to determine the stratigraphic origin and the early depositional environments of unprovenanced vertebrate remains. In this study, the REE composition of more than 60 vertebrate fossils, among them reworked and in situ remains from the Mecsek Mountain, were analysed. The results allowed separation between the Badenian, Sarmatian, and Pannonian aged fossils. The REE content and their distribution also helped us characterise the ancient depositional conditions of the investigated reworked fossils. Furthermore, several different types of vertebrate fossils were analysed, resulting in a large database that helped clarify the likely timings and mechanisms of REE uptake at this locality. Apparent variation in REE chemistry within bones (cortical vs cancellous) and teeth (enamel vs dentine) are best linked to fractionation along the REE series during their incorporation.

Upper Cretaceous Limestones as Stone Resources for the Monuments of Oviedo (Asturias, NW of Spain): Petrographic Variability and Stratigraphic Origin

This study offers an analysis of the petrographic variability and the stratigraphic origin of the rocks used as building stones in the vast majority of the historical monuments of Oviedo, including UNESCO World Heritage Sites. More than a hundred samples of Upper Cretaceous stone were obtained from monuments and outcrops. Based on petrographic characteristics, a macroscopic scale classification was established, and two lithotypes were identified, Piedramuelle and La Granda. Further varieties were differentiated at a microscopic scale: five in the first lithotype and two in the second one. Regarding stratigraphic origin, both rock types come from the Upper Cretaceous San Lázaro and Oviedo Formations. The building stones were mostly extracted from quarries located in the surroundings of the city and, in some cases, within the urban area. The lithotype used in monuments built up to the eighteenth century is Piedramuelle, while La Granda dominates in buildings erected during the seventeenth and eighteenth centuries.

Dermal tubercles and bucklers of gigantic stingrays (Dasyatidae) from the Pleistocene of South Carolina and the stratigraphic origin of “Ceratoptera unios” Leidy, 1877

Dermal tubercles and bucklers of gigantic stingrays (Dasyatidae) from the Pleistocene of South Carolina and the stratigraphic origin of “Ceratoptera unios” Leidy, 1877

‘X’ marks the spot! Sedimentological, geochemical and palaeontological investigations of Upper Cretaceous (Maastrichtian) vertebrate fossil localities from the Vălioara valley (Densuş-Ciula Formation, Hațeg Basin, Romania)

At the beginning of the 20th century, the Croatian-Hungarian palaeontologist Ottokár Kadić discovered a rich Late Cretaceous vertebrate assemblage around Vălioara in the Haţeg Basin, including fossils of several dinosaurs and the lectotype of the eusuchian Allodaposuchus. These fossils were collected from seven main localities and have been housed in the collections of the Mining and Geological Survey of Hungary. However, the collection was mixed after World War II, and this unprovenanced material currently cannot be used for palaeoecological investigations. Nevertheless, the map marking the location of Kadić’s sites has been recently uncovered, showing the positions of the fossiliferous localities, which allows matching these with the historically collected specimens using geochemistry. Based on Kadić’s map, we georeferenced, relocated, and re-excavated these vertebrate-bearing outcrops, and documented their sedimentological context. Detailed stratigraphical investigations of the exposed successions indicate that this Vălioara material represents one of the oldest (earliest Maastrichtian) Late Cretaceous faunal assemblages known from the Haţeg Basin. The vertebrate remains collected during our new excavations around Vălioara represent turtles (Kallokibotion), crocodyliforms (Allodaposuchus, Doratodon, ‘Theriosuchus’, Acynodon), dinosaurs (Zalmoxes, Telmatosaurus, titanosaurs, theropods), and mammals. In order to determine potential geochemical differences among the sites, we selected several specimens with recorded stratigraphic position, measured their trace element compositions, and used these as independent proxies to assess the probable stratigraphic origin of the historical vertebrate fossils. Our detailed sedimentological, geochemical and palaeontological investigations around Vălioara contribute to a deeper understanding of the distribution, evolution and palaeoecology of the Haţeg vertebrate faunas during the latest Cretaceous.

Geochemical analyses suggest stratigraphic origin and late Miocene age of reworked vertebrate remains from Penanjong Beach in Brunei Darussalam (Borneo)

ABSTRACT We report on sporadic fossil vertebrates from Brunei Darussalam (Borneo). Most of these isolated remains are reworked and derive from Penanjong Beach known for former coastal cliffs used to be rich in marine molluscs. Previously, the only vertebrate remains reported were shark teeth. With new material, the fish fauna is now represented by six shark and a single ray taxa, while remains of three turtle families were discovered (Trionychidae, Cheloniidae, Geoemydidae). This fauna is compared to nearby upper Miocene fossiliferous beds from where remains of cheloniid and trionychid turtles were unearthed. To assess the origin of the reworked remains, rare earth element (REE) concentrations of the fossil bioapatite were compared between the reworked and the geographically closest in-situ Ambug Hill fauna. The obtained trend in REE variations are identical, revealing similar REE uptake mechanism and early diagenetic conditions. With the additional fact that the succession outcropping at Ambug Hill cuts the coastline imply that the majority of the reworked fossils derive from the local Miocene beds. This is supported by Sr-isotope ages from reworked calcite bivalve shells ranging from 9.74 to 6.62 Ma. These turtle remains thus represent the hitherto known first Neogene fossil tetrapods from Borneo.

What factors influence our reconstructions of Morrison Formation sauropod diversity?

The Upper Jurassic Morrison Formation classically represents the “Golden Age” of sauropods, and the Morrison Formation is reported to have yielded 13 genera and 24 species of sauropods. This incredible diversity has produced numerous theories attempting to reconcile the co-occurrence of such large, and similar taxa. Previously, a comparably high diversity has been proposed for the Late Cretaceous Hell Creek Formation of North America – possibly comprising nearly three dozen species from over 20 genera of ankylosaura, caenagnathids, ceratopsians, dromaeosaurids, hadrosaurs, ornithomimids, pachycephalosaurs, thescelosaurs, and tyrannosaurs. However, much of the morphologic variation previously ascribed to taxonomic differences has recently been shown to be a result of stratigraphy and/or ontogeny – resulting in this rich assemblage being downsized to 13 genera and 16 species. Whereas still rich in diversity, such factors have an immediate effect towards our reconstruction of true richness.Following the example of the Hell Creek Formation, we can investigate the ontogenetic and strati-graphic origin of possible diversity inflation in other formations, and within this study, apply it to the Morrison Formation. New dating techniques are resulting in finer temporal resolution, and are changing the temporal position of well-known quarries. Differences in body size and ontogenetic stages can also affect diversity estimates. Plotting body size stratigraphically, it initially appears that larger specimens (interpreted as different species) occur higher in the section. An increase in average body size may be a legitimate trend, but there are several specimens that counter this “rule” for many genera. Likewise, dramatic allometric ontogenetic trajectories have led to the erection of at least three diplodocid genera – Amphicoelias, Seismosaurus, and Suuwassea – and it is suspected that many more Morrison Formation “species” could alternatively be explained as ontogimorphs. We have a long way to go towards revealing the true nature of Morrison Formation sauropod diversity. Although dietary partitioning undoubtedly occurred at the level of both the species (e.g., Brachiosaurus vs. Diplodocus) and between ontogenetic stages, a base of 24 levels of co-occurring divisions seems unlikely. The Morrison Formation may have exhibited a sauropod-rich assemblage unlike any other in North America, and the implications of stratigraphy, ontogeny, and variation may be minor, yet these factors alter perceived “diversity.” True diversity will not be fully understood unless these factors are considered.

A new straight-tusked elephant tooth from Soulac-sur-Mer (Gironde, France). Review of elephant discoveries in the northern Médoc

Coastal erosion in the northern Medoc region has uncovered Middle Pleistocene straight-tusked elephant (Palaeoloxodon antiquus) remains in the L’Amelie beach area, south of Soulac-sur-Mer (south-west France). First to be discovered was a mandible published in 1875. Since then, some fragments in 1971, a partial skeleton in 1994, and a mandible as well as an isolated tooth in 2000 have been discovered. Here we present an additional specimen, an upper molar found by Pauline Debruges in 2014. Over the past three years, a tusk of nearly two metres in length and a vertebra have been recovered. These elements allow us to improve our understanding of this fossil species, to clarify the stratigraphic origin of the remains and to discuss the age of the clayey formations in which they were embedded.

First Report of Redeposited Cretaceous Radiolarians in the Eocene Sand-Shale Member of Zhepure Formation, Tüna, Yadong, Tibet

Cretaceous radiolarians were firstly reported from the Eocene Sand-Shale Member of Zhepure Formation in the Gulupu section, Tuna, Yadong, Tibet. In spite of poor preservation, 24 species of 14 radiolarian genera have still been identified, clearly indicating an age, ranging from early Aptian–Maastrichtian, and therefore should have occurred in the Eocene as a result of redeposition. The study of the stratigraphic origin of these radiolarians will shed light on the paleoenvironment and late evolutionary history of the Tibet-Tethys.

A late surviving Pliocene seal from high latitudes of the North Atlantic realm: the latest monachine seal on the southern margin of the North Sea.

BackgroundThe family of true seals, the Phocidae, is subdivided into two subfamilies: the southern Monachinae, and the northern Phocinae, following the subfamilies’ current distribution: extant Monachinae are largely restricted to the (sub-)Antarctic and the eastern Pacific, with historical distributions of the monk seals of the genus Monachus in the Caribbean, the Mediterranean and around Hawaii; and Phocinae to the northern temperate and Arctic zones. However, the fossil record shows that Monachinae were common in the North Atlantic realm during the late Miocene and early Pliocene. Until now, only one late Pliocene record is known from the Mediterranean, Pliophoca etrusca from Tuscany, Italy, but none from farther north in the North Atlantic.MethodsWe present the description of one partial phocid humerus collected in the early 20th century from the Antwerp area (Belgium), with an assessment of its stratigraphic origin using data from the literature.ResultsThe studied humerus was recovered during construction works at the former Lefèvre dock in the Antwerp harbour (currently part of the America dock). Combining the information associated to the specimen with data from the literature and from local boreholes, the upper Pliocene Lillo Formation is ascertained as the lithological unit from which the specimen originates. Morphologically, among other features the shape of the deltopectoral crest and the poor development of the supinator crest indicates a monachine attribution for this specimen. The development of the deltopectoral crest is closer to the condition in extant Monachinae than in extinct Monachinae.DiscussionThe presented specimen most likely represents a monachine seal and a literature study clearly shows that it came from the latest early to late Pliocene Lillo Formation. This would be the first known monachine specimen from the latest early to late Pliocene of the North Sea, and more broadly from the northern part of the North Atlantic realm. This humerus differs from the humerus of P. etrusca and suggests a higher diversity of Monachinae in the latest early to late Pliocene than previously assumed.

Well flow and dilution measurements for characterization of vertical hydraulic conductivity structure of a carbonate aquifer

The paper aims to characterize vertical variations in horizontal hydraulic properties in a fractured carbonate aquifer, the Cretaceous Chalk in East Yorkshire, UK. Two approaches are used: an inverse model of well flow applied to flow logs of pumped open wells, and open well dilution testing. In this case study, transmissivity in the unconfined part of the aquifer is dominated by the highly permeable zone of water table fluctuation, where carbonate dissolution has occurred enhancing fracture aperture; a similar enhanced permeability zone is present at the top of the aquifer where it is confined beneath glacial deposits, although periglacial physical weathering during Quaternary cold periods, rather than carbonate dissolution, is responsible. The aquifer is also shown to contain deeper permeable horizons of stratigraphic origin, which are better developed in the unconfined section.

O final do ciclo gráfico paleolítico do Vale do Côa: A arte móvel do Fariseu (Muxagata, Vila Nova Foz Côa)

We present in this work the integral study of the portable art of Fariseu (Coa Valley). Eighty-five engraved pieces and four painted ones form the studied collection. The chronological attribution to the Late Dryas/ beginning of the Pre-boreal is perfectly assured by the stratigraphic origin of the pieces. The technical and stylistic attributes of the figures are similar to some of the rock art of the Coa valley, making the collection an important chronological referent to a vast number of engraved and painted panels of the region. Those technical and stylistic attributes are also similar to others from Southwest Europe that are dated from the end of the Late glacial period, which denotes the affiliation of this rock art facies in a graphic tradition of a broader geographic range.

須恵器(土器)から発見された中新世中期の放散虫化石と胎土の起源となった層準の推定

須恵器(土器)から発見された中新世中期の放散虫化石と胎土の起源となった層準の推定

Establishing the integrity and stratigraphic origin of stone artefact scatters on the surface of the Lake Mungo lunette in south-eastern Australia

Refitting is routinely employed to investigate the techniques used to make and modify stone tools, to assess the impact of post-depositional processes on archaeological assemblages and to identify the locations of task-specific activities. However, it is rarely used to facilitate the study of surface archaeological assemblages, despite its obvious potential for assessing the impact of post-exposure processes on artefacts strewn across the surfaces of eroding landforms. During a recent survey of in situ archaeological traces exposed on the surface of the Lake Mungo lunette in south-eastern Australia, the presence of refitting artefacts, and flakes arguably struck from the same block of raw material, have been used to identify surface assemblages that retain behavioural integrity even though their encasing sediment has been removed. Analysis of the distribution of these artefacts in relation to each other and to stratigraphic and topographic boundaries provides a way of distinguishing lag and/or transported assemblages from those which lie on the surface of the stratigraphic unit from which they originated.

La paleontología de los vertebrados en Argentina desde la segunda mitad del siglo XX hasta nuestros días: un estudio cuali-cuantitativo basado en Ameghiniana

El objetivo de este trabajo es analizar la evolución de la Paleontología de Vertebrados en Argentina, tomando como fuente la revista Ameghiniana. Utilizando todos los documentos sobre Paleontología de Vertebrados publicados en dicha revista en el período 1957-2014, se cuantificaron aspectos como el número de trabajos publicados, el número de firmas (totales y por trabajo), los porcentajes de autores hombres y mujeres, la procedencia del primer autor, la procedencia geográfica de los fósiles, la representación de los grandes intervalos temporales (eras y períodos) y los temas considerados. Se analizaron un total de 668 documentos. Los resultados muestran a lo largo del periodo un incremento en el número de trabajos y en el número de autores por trabajo (esto último, fundamentalmente a partir de los ?80). Asimismo, se observa un incremento en la cantidad de autorías masculinas y femeninas, en una disciplina aun masculinizada pero que muestra una promisoria tendencia hacia la paridad/equidad de géneros. Predominan las autorías únicas y dobles. La mayoría de los documentos tienen investigadores argentinos como primeros autores (especialmente de La Plata). En relación con la representación de los grandes intervalos temporales, predominan los trabajos sobre el Cenozoico y, dentro de esta Era, del Neógeno. En cuanto a los temas principales, predominan los trabajos taxonómicos. Los taxones más estudiados son los mamíferos (fundamentalmente roedores y xenartros) y los reptiles (dinosaurios). Los fósiles considerados provienen principalmente de Argentina (especialmente de Patagonia, seguidos por los de la región Pampeana). Los resultados obtenidos son explicados en el contexto histórico en el que se ha desarrollado la disciplina en la Argentina.

Upper Cretaceous radiolarians reworked in the Eocene London Clay Formation, SE England

Radiolarians were recently discovered in the lower Eocene London Clay Formation of the London Basin from samples in a drainage borehole in the River Thames. They come from a c. 10 m thick sequence of silty shales in the lower part of the formation. The radiolarians are, in general, rather poorly preserved, with the exception of six samples that yielded moderately preserved radiolarians that allowed the identification of eighteen taxa. All radiolarians observed are of Late Cretaceous age and they are therefore reworked into the lower part of the Eocene London Clay Formation. The best preserved sample yielded an assemblage of twelve morphospecies, including Diacanthocapsa ovoidea , Theocapsomma amphora and Theocapsomma sp. aff. T . amphora sensu Popova-Goll et al. 2005, suggesting an original Santonian–Campanian age, and more likely only the Campanian. However, the stratigraphic origin of these radiolarians from the Upper Cretaceous sequence of the London Basin is uncertain.

L’abbé Bacheley et la découverte des premiers dinosaures et crocodiliens marins dans le Jurassique des Vaches Noires (Callovien/Oxfordien, Normandie)

Georges Cuvier published in 1808 the first scientific descriptions of dinosaur and marine crocodilian (Thalattosuchia) remains from the collection of a certain “Abbé Bachelet [sic]”, a naturalist in Rouen (Normandy, France). According to Cuvier, “Bachelet” never published any papers about the circumstances of the discovery of these fossils. Since then, there has been some doubt about their precise geographic and stratigraphic origin. This article reveals for the first time the identity of Charles Bacheley (1716–1795) and presents the biography of this pioneer in Norman palaeontology. He is the author of a note published in 1778 on the petrifactions found on the coast of Pays d’Auge (Calvados) between the Vaches Noires and Trouville-sur-Mer. This study has gone completely unnoticed and reveals that the specimens from the Bacheley collection studied by Cuvier come from the “Marnes de Dives” (Upper Callovian) or the “Marnes de Villers” (Lower Oxfordian) of the Vaches Noires cliffs. Bacheley identified these dinosaurs and marine crocodilian remains as belonging to “fishes,” which at that time also included cetaceans according to popular usage. Interestingly, Bacheley did not exclude the possibility that these petrified bones could belong to animals distinct from living forms.