bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mammalian biostratigraphy across the Paleocene-Eocene boundary in the Paris, London and Belgian basins
Authors: Hooker J. J. 
Published: April 2008

Abstract
Problems of resolution and poor superpositional evidence in mammalian biostratigraphy through Paleocene-Eocene boundary strata in NW Europe are solved by applying parsimony analysis to taxa shared between localities. On this basis, five biozones are established in the area for the interval formerly delineated by mammalian biostratigraphers as MP7-MP9. Integration with other biostratigraphies (dinocyst, calcareous nannoplankton, charophytes) aids correlation between the London, Belgian and Paris Basins, and supports the earlier idea of diachronism of the ‘argile à lignites’ facies. The advent of ‘Sparnacian’ mammal faunas in Europe may coincide with a carbon isotope excursion recently recognized in the Paris Basin. This would support recent views on essential synchronism of the beginnings of both the North American Wasatchian and European ‘Sparnacian’ land mammal ages.
A forward-modelling analysis of the controls on sequence stratigraphical geometries
Authors: Burgess P. M. , Allen P. A. 
Published: April 2008

Abstract
The sequence stratigraphical depositional model has concentrated primarily on eustasy and tectonic subsidence as the dominant controls on sequence development, with variations in other factors such as sediment supply playing only a modifying part. Little consideration has been given to the significance of the uniqueness problem to the model predictions. Thus it is often assumed that if the sequence stratigraphical model can provide a simple fit with the available data, then it must be the correct and unique solution. This is rarely likely to be the case. Using a quantitative forward model it is possible to reproduce the basic geometries of type 1 and type 2 sequences and then to assess, via a series of sensitivity tests, the significance of some other controls. Use of this forward-modelling approach suggests that fluvial profile behaviour is a first-order control on sequence geometries. It also suggests that variations in the magnitude of sediment supply can significantly alter the development of transgressive ravinement surfaces. These two examples highlight the importance of the uniqueness problem to the sequence stratigraphical model.
High resolution sequence biostratigraphy: examples from the Gulf of Mexico Plio-Pleistocene
Authors: Armentrout John M. 
Published: April 2008

Abstract
High resolution sequence biostratigraphy provides a framework for the construction of palaeogeographic maps for each phase of relative sea-level change. The late Pliocene and Pleistocene of the Gulf of Mexico provides a case history of the integration of this methodology. The strata are abundantly fossiliferous and stratigraphically thick so that exploration well samples provide a record of glacial/interglacial cycles with a 200–300 ka frequency. The methodology developed is suitable for other stratigraphic intervals where microfossils are relatively abundant.
High frequency sequence stratigraphy of a siliciclastic influenced carbonate platform, lower Moscovian, Amdrup Land, North Greenland
Authors: Stemmerik Lars 
Published: April 2008

Abstract

The Moscovian succession in southern Amdrup Land, North Greenland consists of seven, 40–135 m thick, third-order depositional sequences of mixed carbonates, siliciclastics and evaporites. The sequences have sheet-like or wedge-shape geometries and are composed of stacked high frequency sequences with a duration of
c.
100 000 years. The Kap Jungersen 2 Sequence delineates an up to 135m thick carbonate platform composed of 10 high frequency sequences. Each individual high frequency sequence shows great lateral facies and thickness variations. In the platform area they are dominated by bioclastic grainstones,
Palaeoaplysina
-phylloid algae build-ups and bryozoan build-ups. Deposition took place mainly during sea-level highstands; the transgressive systems tracts are generally thin and shaley, and sea-level lowstand led to subaerial exposure and karstification.
Inclination error linked to sedimentary facies in Miocene detrital sequences from the Vallès-Penedès Basin (NE Spain)
Authors: Garcés M. , Parés J. M. , Cabrera L. 
Published: April 2008

Abstract

Palaeogeographic reconstructions based on kinematic and other integrated models are rarely in perfect agreement with palaeomagnetic data. Furthermore, the reliability of rocks that record the geomagnetic field is often questioned, particularly for detrital remanent magnetization (DRM). Among the diverse types of magnetization bias,
inclination shallowing
caused by several mechanisms such as gravitational torques upon deposition and post-depositional compaction can be a major source of error in palaeolatitudinal estimations. Inclination shallowing for a variety of fine-grained alluvial sediments from the Neogene Vallès-Penedès Basin (NE Spain) has been observed to be dependent on sedimentary facies. The correlation of inclination shallowing to sediment fabric is investigated in samples from 11 stratigraphic profiles. Each profile has a dominant lithology, from thinly laminated to edafized silts and massive muds and breccias. A measure of particle alignment in sediment can be determined by means of the
degree of anisotropy (P)
and
shape symmetry (T)
AMS parameters. Since each sedimentary facies shows a particular range of
P
and
T
, a representative mean AMS ellipsoid can be estimated from each lithologically homogeneous profile. Estimated mean remanence inclination (
I
NRM
) has a strongly consistent relationship to the mean AMS ellipsoid and a positive linear correlation is inferred between ln (
P
) and ln tan (
I
NRM
). Given the extreme case of no sediment anisotropy, i.e.
P
= 1, inclination error would be cancelled and
I
NRM
would record the true magnetic field inclination of the sampling site. The regression function predicts a corrected magnetic inclination of 60°, consistent with that of the expected geomagnetic dipole for the studied site and age.
A magnetostratigraphic study of the onset of the Mediterranean Messinian salility crisis; Caltanissetta Basin, Sicily
Authors: McClelland E. , Finegan B. , Butler R. W. H. 
Published: April 2008

Abstract

The Messinian ‘salinity crisis’ marked a dramatic climatic change in the Mediterranean region. The timing and extent of this event remain controversial, with conflicting models ranging from predictions of rapid and catastrophic dessication of all of the Mediterranean basin at once, to progressive draw-down of sea-level causing gradual onset of evaporite formation starting at the margins of the Mediterranean Sea. In this paper the preliminary magnetostratigraphy is described of two sections in the Neogene Caltanissetta basin, Sicily, containing the early Messinian Tripoli Formation, which pre-dates evaporite formation, and the overlying Calcare di Base shallow water carbonates that mark the first evaporite phase. The magnetisation of the sediments has been extensively overprinted by recent weathering, but primary or early diagenetic remanences which pass reversal and fold tests have been isolated. This has been possible because the sections have been tilted by Pliocene tectonic movements, thus rotating the pre-tilt remanence direction away from the later overprint direction, allowing resolution of the components by great circle analysis. The sections have been correlated with Krijsman
et al
.’s revision of the geomagnetic polarity time scale (GPTS) of Cande & Kent. This was achieved by comparing variations in the sediment rate derived from the alternative matches with the GPTS with the observed proportions of diatomite (relatively fast deposition) and clay (slow deposition). The proposed correlation puts the base of both sections at or close to the start of the Messinian, but predicts diachroneity in the onset of Calcare di Base deposition between the two sections, as the base of the Calcare di Base falls in opposite polarity chrons in the two sections. The sections lie in two separate sub-basins controlled by thrust anticlines of the Maghrebian thrust belt. Structural and sedimentological evidence suggests that the onset of evaporite formation in these perched basins was strongly controlled by the extent and development of the emerging anticlines. The magnetostratigraphy provides a first positive test of this prediction of tectonically controlled diachroneity of facies. Further palaeomagnetic work is in progress to assess the relative timing of evaporite formation on Sicily in more detail.
Palaeomagnetic investigations in Northern Albania and their significance for the geodynamic evolution of the Adriatic-Aegean realm
Authors: Mauritsch H. J. , Scholger R. , Bushati S. L. , Xhomo A. 
Published: April 2008

Abstract
Palaeomagnetic results from the Inner and Outer Albanides south of the Shkoder-Pec line have established a clockwise rotation of about 45° for all tectonic units investigated so far. In Northern Albania, different tectonic zones surrounding the Shkoder-Pecline were sampled at 56 sites consisting of about 400 samples. Less than 50% of the samples had sufficiently high NRM intensities for thermal demagnetization and magnetization vector analysis. Fold and reversal tests support the results. The palaeomagnetic directions demonstrate a strong tectonic disturbance in the central part of the study area. The northernmost sites in the Albanian Alps show counterclockwise rotation (with respect to present north) in agreement with results from the Southern Dinarides. The pattern favours the idea that the Shkoder-Pec line is the transition zone between the counterclockwise rotation in the north and the clockwise rotation in the south.
Implications of ophiolite palaeomagnetism for the interpretation of the geodynamics of Northern Greece
Authors: Feinberg H. , Edel B. , Kondopoulou D. , Michard A. 
Published: April 2008

Abstract

Independent studies undertaken in Northern Greece (Axios-Chalkidiki belt and Vourinos massif), mainly on ophiolites but also on granites and metasediments, have shown that despite the occurrence of widespread remagnetizations it is possible to find a consistent arrangement of palaeomagnetic directions. Application of the fold test to four sites in the Kassandra peninsula, comprising pillow lavas and overlying metaflysch deposits demonstrates that the main regional magnetic component (
D
= 47.7°,
I
= 47.7°, α
95
= 8.8°) is a post-folding remagnetization. A comparison with directions found in the Sithonia granite shows that this component was probably acquired during the late-metamorphic emplacement of this granite (in the Eocene). An older component (
D
= 325.4°,
I
= 34.1°, α
95
= 18°) defined at a site in the sediments of the Kassandra area is also present in the ophiolites. This direction has probably been acquired during Late Jurassic-Early Cretaceous times. Further comparisons with the directions found in the Axios-Chalkidiki-Vourinos ophiolites and Florina granite show that the Mesozoic component is consistently found over a broad area.

The Cenozoic clockwise rotation of about 45° shown by the Eocene remagnetisation has been widely described by various authors, but the Mesozoic rotation indicated by the oldest component has been less investigated. This counterclockwise rotation is in the same sense as the rotation of the African plate during the Mesozoic, but is of larger amplitude. This suggests that: (i) Northern Greece was part of the African foreland before the Alpine collision; and (ii) oceanic spreading south of the Pelagonian zone during Cretaceous times would have increased the rotational movement of the studied area with respect to Africa.
Magnetic stratigraphy procedures in volcanic areas: the experience at Vesuvius
Authors: Incoronato Alberto 
Published: April 2008

Abstract

A procedure involving stringent criteria for the definition of a linear vector, combined with visual assessment, is demonstrated to be essential for magnetic dating of volcanic lavas during historical times and that the partial demagnetization process must be extended to where the entire spectrum has been destroyed. As a result, it is demonstrated that some magnetic dating of Medieval lavas on Vesuvius are incorrect. Five flows are shown to have identical directions of magnetization,
D
= 13°,
I
= +64° (α
95
= 0.9°) which can be shown to date to the
AD
1631 ‘big eruption’, confirming that this eruption produced several lava flows, despite recent reports to the contrary. It is also shown, mainly using data from Etna, that five other flows on Vesuvius correspond to separate eruptions during a time span between the nineth and eleventh centuries.
Correlation of the Salawati and Tomori Basins, eastern Indonesia: a constraint on left-lateral displacements of the Sorong fault zone
Authors: Charlton Tim R. 
Published: April 2008

Abstract
The Salawati Basin of western New Guinea and the Tomori Basin of eastern Sulawesi, Indonesia, are two sedimentary basins located either side of the main fault strands in the Sorong fault zone strike-slip system. It is suggested that prior to displacement on the Sorong system the two formed a single sedimentary basin. Movement on the Sorong system occurred largely during the latest Miocene-Quaternary, contemporaneous with deposition of a clastic sedimentary succession. An older basinal sequence, essentially Miocene in age, is composed predominantly of carbonate sediments, and this may have formed part of the foreland basin sequence related to the east Sulawesi orogenic belt. Correlation of the Salawati and Tomori Basins implies a left-lateral displacement of about 900 km on part of the Sorong fault zone.
Evidence for microbial influence on the development of Lower Carboniferous buildups
Authors: Pickard Neil A. H. 
Published: April 2008

Abstract

Following a series of mass extinction events towards the end of the Devonian (Frasnian), true skeletal reef-building organisms were effectively lost from latest Devonian (Famennian) and Lower Carboniferous (Dinantian) marine ecosystems. Nevertheless, nonskeletal, mud-dominated buildups (mud-mounds) are common throughout this geological interval, and microbial activity (fungi, algae and/or bacteria) is considered to have played a significant role in the development of these buildups. Evidence of microbial activity in Dinantian buildups may be divided into two broad categories: (a) direct evidence, such as the development of stromatolitic and thrombolitic macrostructures, presence of cryptic incrustations and preservation of calcimicrobes such as
Renalcis
; (b) cryptic evidence, in the form of peloidal ‘mud’ which forms the matrix of many Dinantian buildups. The matrix peloidal micrites closely resemble modern microbially mediated (algal and bacterial) carbonate precipitates. Precipitation of the peloidal fabrics is considered to have occurred within a microbial mat that bound the accreting buildup surface, thereby allowing steep depositional slopes to develop in deep water buildups and protecting shallow water buildups from erosion. Extensive cavity systems, often developed in Dinantian buildups, may also contain stromatolitic mats and micritized cavity walls. These fabrics indicate the additional presence of internal heterotrophic microbial communities and suggest that a diverse range of microbes were present in Dinantian buildups.

Controls on the development of Dinantian buildups are likely to have been multiple. Nutrient-rich (mesotrophic) water masses, in combination with relatively low sedimentation rates, may have promoted buildup initiation, while regional palaeogeography and tectonic events played a role in their location. Tournaisian buildups commonly developed in a wide range of water depths on carbonate ramps, whereas Viséan buildups, particularly in northwestern Europe, were often restricted to relatively shallow water over tectonically controlled topographic highs.

Evolution of new organisms during mid-Carboniferous time led to a diversification of buildup types. However, microbial fabrics identical to those developed in Dinantian buildups are still present in many late Carboniferous and Permian phylloid algal,
Palaeoaplysina
and bryozoan buildups. The role of microbial activity in the development of these late Carboniferous and Permian buildups may have been greatly underestimated.
Constituent composition of Early Mississippian carbonate buildups and their level-bottom equivalents, Sacramento Mountains, New Mexico
Authors: Ahr Wayne M. , Stanton Robert J. 
Published: April 2008

Abstract
The Alamogordo Member of the Lake Valley Formation (Lower Mississippian-Tournaisian to early Viséan) was deposited on a homoclinal ramp at depths below the fair-weather wave-base and mainly below the photic zone. Depth increased toward the present southwest, and the level-bottom biota of the Alamogordo Member is present in assemblages that parallel the depth gradient (Jeffery & Stanton this volume). Waulsortian-like mounds are abundant in the Alamogordo, Nunn and Tierra Blanca Members of the Lake Valley Formation on the distal portion of the homoclinal ramp. These mounds contain essentially the same biota as the Waulsortian buildups of Europe. Alamogordo mounds are low, tabular features composed mainly of spiculiferous micrite, while Nunn and Tierra Blanca mounds are more domical and are composed largely of fenestrate bryozoan cementstone.
Lithology and biota of coeval, level-bottom beds and mounds differ significantly because of habitat differences (cavities and hard substrates in and on mounds), and because of taphonomy, an example of which is the preservation of fenestrate bryozoan sheets in radiaxial fibrous calcite cements on mounds as compared with comminuted and dispersed fenestrate hash in level-bottom muds. Lake Valley mound constituents, although essentially identical to those in the European Waulsortian, do not occur in regular growth ‘phases’ like those described by Lees & Miller (1985). The difference is interpreted to mean that the New Mexican mounds lacked enough vertical relief above the sea floor in deep water to have been affected by any environmental gradients that may have existed across the entire platform.
Episodic growth of a Waulsortian buildup: the Lower Carboniferous Muleshoe Mound, Sacramento Mountains, New Mexico, USA
Authors: Kirkby Kent C. , Hunt Dave 
Published: April 2008

Abstract
Muleshoe Mound is a composite Waulsortian buildup that crops out along the western escarpment of the Sacramento Mountains, New Mexico. Exceptional exposures of Muleshoe Mound have enabled a detailed stratigraphic model to be developed, subdividing the buildup into five separate stratal units. Each stratal unit differs in facies, geometry and symmetry, reflecting changes in the character and intensity of different environmental conditions (energy, carbonate production, oxygenation and accommodation space). Hiatal surfaces mark periods of mound crisis and/or sea-level fluctuations. These hiatal surfaces highlight the episodic nature of the mound’s growth. Episodic growth acted as an important control on this buildup’s development, facies and early diagenesis. Features and patterns of the Muleshoe Mound conflict with the traditional interpretation of the Waulsortian as quiet, stable, deep-water buildups. Muleshoe Mound appears to have grown in appreciable currents where accommodation space was a crucial control on growth.
Dinantian depositional environments along the northern margin of the Solway Basin, UK
Authors: Maguire Kelly , Thompson Jillian , Gowland Stuart 
Published: April 2008

Abstract
A sedimentological study has been conducted on the Dinantian strata of the tectonically separated Rerrick and Kirkbean Outliers on the northern margin of the Solway Basin. The Rerrick succession, comprising a sequence of largely non-marine alluvial fan, fluvial and coastal plain clastic rocks, represents a tectonically influenced lateral dispersal system sourced from the northern margin of the Solway Basin. In contrast, the Kirkbean succession is considered to represent the deposits of a tectonically stable shallow-marine shelf subject to both limestone and clastic deposition. Periodically, axial fluvial systems draining westward established delta front conditions on the shelf. The depositional model presented here suggests both lateral and axial dispersal systems were active within the Solway Basin during the Dinantian.
A palynofacies analysis of the Dinantian (Asbian) Glenade Sandstone Formation of the Leitrim Group, northwest Ireland
Authors: Smith Jim 
Published: April 2008

Abstract
A quantitative palynofacies analysis of the Dinantian (Asbian) Glenade Sandstone Formation in two boreholes from the Glangevlin area, northwest Ireland, was carried out. It was found that the sands of the Glenade Sandstone Formation prograded rapidly over an arid lagoonal environment in the area of the more proximal northern borehole, but were deposited directly on top of the laminated dolomites of the underlying Meenymore Formation in the area of the southern borehole. Fluvial conditions predominated in the northern area, while lagoonal conditions were established in the southern area, before a major anoxic marine transgression, 12.7 m above the base of the Glenade Sandstone Formation in both areas, submerged the flat landscape. In both areas the dominantly fluvial environment above the marine transgression was periodically replaced by more lagoonal environments.
The flora at the time of deposition of the Glenade Sandstone Formation may have been dominated by ferns, tree-ferns and small seed-ferns, while herbaceous and arborescent lycopods, typically present in Carboniferous coal swamps, may have been absent.
Tsunami waves generated by volcanic landslides: an assessment of the hazard associated with Kick ’em Jenny
Authors: Smith M. S. , Shepherd J. B. 
Published: April 2008

Abstract
Landslides and rock falls generating tsunamis constitute a serious element of risk at steep-sided volcanoes located in close proximity to water, especially when the volcano’s structure is cut by faults or altered by fumaroles and where there has been a history of subsidence or signs of incipient caldera formation. Approximately 5% of known tsunami events have been generated by volcanoes, producing some of the most destructive tsunamis on record. A preliminary study suggests that Kick ’em Jenny is a prime candidate for tsunamigenic events on a potentially hazardous scale, possibly affecting the whole of the eastern Caribbean region. An estimate of the potential height of tsunami waves generated following slope failure on the flanks of Kick ’em Jenny has been found using the basic solitary wave theory combined with equations of energy conservation. Generally, landslide-generated tsunamis possess little energy and, unless they are confined in a bay or channel, are only hazardous close to the source. However, the results show that with the low-lying Grenadine Islands situated a few kilometres to the east, even a relatively small landslide event at Kick ’em Jenny has the potential to produce waves that would prove hazardous to both coastal populations and ships.