bluuebunny/crossref_metadata_2025_split huggingface dataset:
The relevance of iridium and microscopic dynamic deformation features toward understanding the Cretaceous/Tertiary transition
Authors: Officer Charles B. 
Published: July 2007

ABSTRACTIridium enhancements are associated with the fine particle emanations from present day basaltic and acidic volcanic eruptions but are not associated with impact craters, with one possible exception of Precambrian age. Microscopic dynamic deformation features are associated with structures originating from a meteorite impact, volcanic and internal explosion event(s), and high tectonic strain‐rate(s). The Cretaceous/Tertiary (K/T) distributions of inidium and shocked minerals extend over a stratigraphic interval of a few hundred thousand years, in agreement with the known record of intense volcanism at K/T time but not in accord with the signature expected from a single meteorite impact. The recently studied K/T sections in Haiti add further information on the associations of shocked minerals and iridium enhancements.
Ground temperature changes in eastern Canada: borehole temperature evidence compared with proxy data
Authors: Beltrami Hugo , Mareschal Jean‐Claude 
Published: July 2007

ABSTRACTBorehole temperature logs have been inverted to infer ground temperature histories (GTH) in eastern and central Canada. Regional ground temperature histories were obtained by simultaneous inversion of several temperature profiles from the same areas. Simultaneous inversion of 21 temperature logs sampled across all of eastern and central Canada yielded an average solution for this region. All but three of the studied sites show signs of warming in the last 150 years. This period of warming, which started after 1800 AD, was found throughout this part of Canada. The warming followed a cooler period corresponding to the little Ice Age. The inferred ground temperature histories exhibit long‐term trends similar to those obtained from treering growth indices in nearby regions and stable isotope data in the southern hemisphere. The modern warming appears correlated with the atmospheric concentration of CO2 as measured in ice cores.
Time as an independent variable for current ripples developing towards linguoid equilibrium morphology
Authors: Baas Jaco H. , Oost Albert P. , Sztano Orsolya K. , de Boer Poppe L. , Postma George 
Published: July 2007

ABSTRACTFlume experiments show that current ripples on very fine sand surfaces always develop towards a linguoid shape with constant height and wavelength provided that sufficient time is allowed for their formation. Straight and sinuous current ripples only reflect intermediate stages in ripple development and may be regarded as non‐equilibrium bedforms. The time period which current ripples require to reach linguoid equilibrium morphology is related to an inverse power of flow velocity. In the transitional stage from current ripples to upper stage plane bed (i.e. washed‐out ripple stage) only the equilibrium wavelength remains constant, whereas equilibrium height rapidly decreases to zero.Our observations imply that bed‐roughness parameters in sediment transport calculations can be simplified when equilibrium conditions are attained, and that inferences about flow energy from the dimensions of current ripples in very fine sand need to be regarded with caution.
The occurrence and significance of beekite in Palaeocene alluvial‐fan deposits in central Anatolia, Turkey
Authors: Kazanci Nizamettin , Varol Baki 
Published: July 2007

ABSTRACTThe Palaeocene alluvial‐fan succession in central Anatolia, Turkey, contains three isolated zones of beekite‐encrusted clasts. Each zone is 3–5 m thick and c. 1 km long. Beekite is developed as thin (1–5 mm), concentric silica rings formed by replacement and encrustation of carbonate clasts. The formation of beekites requires a relatively long time, with non‐deposition and fluctuating arid/semiarid conditions. The significance of beekite is thus analogous to that of silcrete. The presence of beekite encrustation within the Palaeocene alluvial‐fan succession indicates considerable breaks in sedimentation in the eastern part of the basin, and this inference is supported by the lower thickness of the alluvium in the east.
Analysis of the Kodiak Shelf Basin using 1D and 2D fluid flow/compaction models
Authors: Liu J. , Lerche I. , Wei Z. 
Published: July 2007

ABSTRACTThe Kodiak Shelf Basin is one of the undeveloped basins in Alaska. In surrounding areas, hydrocarbon accumulations have been found. It is of interest to investigate whether there might also be hydrocarbons generated in the Kodiak Shelf Basin.Using both one‐ and two‐dimensional fluid flow/compaction models, together with geological, geophysical and geochemical data from the Kodiak Shelf Basin, we simulate the development with time and depth of sedimentary compaction, porosity, permeability, pressure, palaeoheat flux variation and palaeotemperature variation. We then evaluate quantitatively the maturation of organic matter in the basin. The model results indicate that there was only a low likelihood of hydrocarbon generation in the basin due mainly to the combined effects of a cool palaeothermal history and low organic carbon content.
Seismicity of the Cyprus region
Authors: Ambraseys N.N. , Adams R.D. 
Published: July 2007

ABSTRACTWe have used a combination of macroseismic and instrumental techniques to re‐evaluate the seismicity of Cyprus and the surrounding region for the period 1890–1900. We identified 56 events which we believe to have a surface‐wave magnitude (Ms) of 4.5 or greater. Early events are located by felt effects alone, and macroseismic information is used to improve the location of many later events. We find the broad pattern of seismicity follows that given by standard listings: an area of weak seismicity to the north‐west of Cyprus in the Gulf of Antalia includes intermediate‐depth events as are found in the Hellenic Arc to the west; a gap of reduced activity separates this activity from that of the main region of Cyprus, where we could find no evidence for sub‐crustal foci; there appears to be no present seismological connection along the presumed plate boundary to the north‐east to the junction of the East Anatolian fault and the extension of the Dead Sea rift system. We find a much greater level of activity in the first part of this century than is given in the standard listings, such as that of the ISC. Up to 1963 we identified 47 events of Ms > 4.5, compared with only 10 given in the ISC files. Recent improved station coverage locates more events in the region, but these have not been of large magnitude, and the moment release in recent decades has been appreciably less than earlier in the century. For the events in our list the total moment release is 2.7x 1019 Nm with 75% of this originating in the main Cyprus region. We reaffirm the danger of uncritical use of standard earthquake listings for tectonic interpretation and in particular for hazard evaluation in areas such as this, where neither the historical nor the instrumental seismicity record is complete.
Topography, climate and ice masses: a review
Authors: Kerr Andrew 
Published: July 2007

Topography acts as a filter between regional climate and the consequent response of a glacier or ice sheet. It influences the mass and energy inputs and modifies the ice dynamics. The evolution of the ice sheet surface and, over longer time scales, of the bed topography modulates the climatic forcing.Until we have a better understanding of these topographic linkages, the use of geophysical signals from former ice masses to determine palaeoclimates must be regarded as fundamentally flawed.
Contemporary state of stress and neotectonic deformation in the Carpathian‐Pannonian region
Authors: Becker Arnfried 
Published: July 2007

The Carpathian‐Pannonian region has been characterized by a two‐stage tectonic evolution since the beginning of the Neogene. During early and mid‐Miocene the lateral eastward escape of the Pannonian Fragment caused thrusting and folding in the Outer Carpathian Mountains, south‐ and westward directed subduction of the Eurasian lithosphere, calc‐alkaline volcanism along the Inner Carpathian bend, and localized fault‐controlled subsidence of basins in the Pannonian region. This style of tectonic deformation ceased by the end of the mid‐Miocene. The neotectonic stage began in the late Miocene. It is characterized by differential regional subsidence with maximum rates in the west and east and minimum rates in the centre of the Pannonian Basin. Further characteristics of the central Pannonian Basin are the anomalous high heat flow values, the thin crust and lithosphere.The neotectonic stress field has been determined by in situ stress measurements, the analyses of borehole breakouts and fault‐plane solutions of earthquakes. In situ stress measurements by the doorstopper and triaxial strain cell methods indicate high compressional stresses in the western Pannonian Basin with its maximum in WNW‐ESE to NW‐SE direction. In contrast to its western part, the central Pannonian Basin shows tensional stresses near the Earth's surface with maximum tension in the same WNW‐ESE direction. Borehole breakout data indicate a general WNW‐ESE orientation of maximum horizontal stress in the western part of the Pannonian Basin and in the eastern part as well, whereas in the central Pannonian Basin this direction is the preferred azimuth of minimum horizontal stress.It is suggested that the neotectonic deformations and stresses in the Carpathian‐Pannonian region have a sublithospheric origin.Asthenospheric convection with an upwelling mantle flow below the centre of the Pannonian Basin and downwelling flows along the cold lithospheric roots below the eastern Carpathians and the Alps seems to be most plausible. Accordingly, the relative uplift of the centralPannonian Basin, the high heat flow and also the tensional stresses are explained as the surface expression of an upstreaming branch of a localized convection cell below the Pannonian Basin.
Fake quakes in Italy through parametric catalogues and seismological compilations: case histories and typologies
Authors: Bellettati Daniela , Camassi Romano , Molin Diego 
Published: July 2007

The Italian catalogue contains many earthquakes of moderate to high epicentral intensity which are located in areas of low seismicity and near big cities. Some of them have been inserted in the catalogue after one historical record only. This study investigates many such events in the 1000–1690 time‐window showing that a great number of them are fake.Starting by an operational definition of ‘fake quake’, this paper shows the procedures adopted, and the main results which contribute in a significant way to the reassessment of seismicity and seismic hazard.
A ‘cluster’ of earthquakes in the Apennines at the end of XIII century
Authors: Castelli Viviana 
Published: July 2007

The assessment of seismicity in many areas of Italy hinges on poorly known earthquakes listed by the seismic catalogue on the grounds of single, poor quality data taken from seismological compilations which, in most cases, did not adopt a consistently critical outlook in processing their miscellaneous information. Starting from such datasets it was easy to misunderstand, lose and duplicate evidence and events. This study was initiated to see whether better results might be attained by a more careful reprocessing of the same data already gathered by compilations. Six important, but poorly known, earthquakes were listed by the Italian catalogue in the selected time‐window (1292–1294): according to the results of the study one of them is to be back‐dated by a century, three others should be reduced to one, another can be confirmed and the last one is a fake.The author is indebted to Paola Albini, Romano Camassi, Magda Minoli, Laura Mucci and Massimiliano Stucchi for moral and material support.
Structural and lithological controls on coastline profiles in Fife, Eastern Britain
Authors: Ringrose Philip S. 
Published: July 2007

ABSTRACTThe coastline of southern Fife on the east coast of the British Isles is presented here as an illustration of geological influences on spatial variability at different lengthscales. The coastline profile of Britain is widely referred to as an example of fractal geometry, as presented in Mandelbrot's (1967) original paper on statistical self‐similarity. I show here that at different lengthscales, different geological processes dominate the character of the coastline profile, and that estimates of the fractal dimension are strongly dependant on the scale and choice of sample. Significant periodic components in the tortuosity of the coastline are evident, and can be related to the causative, scale‐specific, geological processes.
High‐temperature geothermal reservoir possibilities in Hungary
Authors: Stegena L. , Horváth F. , Landy K. , Nagy Z. , Rumpler J. 
Published: July 2007

ABSTRACTTheoretical studies have shown the possibility of high‐temperature (‘high enthalpy’) geothermal reservoirs in the pre‐Tertiary rocks at 4–5 km depth range within the Pannonian Basin. This expectation was proven by the hotwater/steam blowout of Fábiánsebestyén‐4 borehole (16.12.85–31.1.86). Exploration efforts carried out during 1987–88 in the broad vicinity of the borehole proved that reservoirs of this type can be found with the combination of seismic reflection, silica‐thermometry and magnetotelluric sounding methods. Deliberate prospection should be continued in all suitable areas within the basin, since high enthalpy reservoirs promise profitable operation of geothermal power stations.
Recent trends in strontium isotope stratigraphy
Authors: McArthur J.M. 
Published: July 2007

ABSTRACTAn introduction to Sr‐isotope stratigraphy can be obtained from several recent reviews (Elderfield, 1986; Veizer, 1989; McArthur, 1991, 1992a). The purpose of this article is not to repeat these reviews but to give to those not expert in the field, but who may be prospective users, a summary of aspects of the method not covered elsewhere, and some examples of recent applications of the technique and the problems that affect it. Highlighting problems inevitably means highlighting the publications in which they occur; I hope the authors will forgive me for spotlighting their work. Neither is this article intended to be a review of all that has been written on the use of Sr isotopes in low‐temperature geochemistry; it concentrates on their use in stratigraphy and dating, rather than how they may be used to elucidate geochemical processes. Many excellent papers are thereby excluded from consideration. Implicit in this article is the view that the successful application of strontium isotope stratigraphy requires an application of good methodology in both geochemistry and stratigraphy.
Closing‐up structures, alternatives to pull‐apart basins; the effect of bends in the North Anatolian Fault, Turkey
Authors: Neugebauer Joachim 
Published: July 2007

ABSTRACTFault blocks passing bends or stepovers in a fault zone must adapt their margins to the uneven fault trace. Two cases of adaption are distinguished for extensional bends or stepovers (transtension): (1) The fault margins close up behind a single bend ('knickpoint') of a strike‐slip fault and a ‘closing‐up structure’ (new term) arises or (2) fault‐block margins are extended behind a releasing bend (double bend) or stepover parallel to the displacement and a pull‐apart basin originates. The dosing up described here is accomplished by acute‐angled synthetic strike‐slip faults that dissect the straight fault in front of a knickpoint to form a zig‐zag block boundary behind it. Crustal extension is also involved in the closing‐up structure, but in a different way from typical pull‐apart basins.The closing‐up structure illustrated was developed behind an extensional knickpoint in the North Anatolian Fault west of Lake Abant, NW Turkey, where the process of closing up continues to this day. The kinematic model of this closing‐up structure is supported by displacements and ruptures observed during the 1967 Mudurnu valley earthquake and the 1957 Abant earthquake.
Mafic enclaves in granitoid intrusions: a catastrophic model of rheological behaviour
Authors: Pesquera A. 
Published: July 2007

ABSTRACTThe significance of mafic enclaves as indicators of magma mixing processes between juxtaposed felsic and mafic magmas is evaluated from a rheological point of view. A qualitative model for explaining strain and morphological changes in the enclaves has been developed on the basis of the catastrophe theory.Mafic enclaves in intrusive granitoids commonly behave as physical systems that can be described using a cusp catastrophe model. Their behaviour is characterized by bimodality, divergence and sudden changes, which are properties typical of this model. Accordingly, the presence of mafic enclaves showing variable strain and morphology within the same granitoid intrusion would be indicarive of mutual interaction and mingling between mafic and felsic magmas. Due to the characteristics of these processes, it is not possible to establish unambiguous age relationships between the two magmatic components.
Palaeozoic sequences and evolution of the Calabrian‐Peloritan Arc (Southern Italy)
Authors: Acquafredda P. , Lorenzoni S. , Lorenzoni E. Zanettin 
Published: July 2007

ABSTRACTThree Palaeozoic sequences belonging to three different basins crop out in the Calabrian–Peloritan Arc. Their age covers the time span from middle (?) Cambrian to early Carboniferous. The sequences comprise terrigenous, volcanic and carbonate rocks, and show low‐grade metamorphism. The basement is of pre‐middle Cambrian age, crops out in the Calabrian–Peloritan Arc, and was metamorphosed prior to the opening to the Palaeozoic basins.The Palaeozoic basins existed no later than the middle Carboniferous, with inferred maximum crustal extension in the Cambro‐Ordovician. By Devonian time, the tectonic regime was compressional overall with middle Devonian island‐arc type volcanic activity that continued until the closure of the basins. Approximately 330 Myr, the Palaeozoic sequences experienced low‐pressure greenschist facies metamorphism and continuing subduction controlled the Variscan tectonogenesis with 280 Myr island‐arc type intrusive magmas. Subduction ceased and late‐stage 280–270 Myr granitic magmas were emplaced during continental collision.The crustal sector carrying the Palaeozoic basins is interpreted as comprising fragments of an active continental margin, one of the several microplates, located at the southern margin of the Euro‐Asia continent which faced a large (at least 1500 km in width) ocean basin.
Palynological dating (Arenig) of the sedimentary sequence overlying the Ishkarwaz Granite (upper Yarkhun valley, Chitral, Pakistan)
Authors: Tongiorgi Marco , Di Milia Anna , Le Fort Patrick , Gaetani Maurizio 
Published: July 2007

ABSTRACTA sedimentary sequence overlying a granite pluton near Ishkarwaz (upper Yarkhun valley, Chitral, Pakistan; Karakorum Microplate) contains abundant, but poorly preserved, acritarchs probably referable to the late early Arenig‐early late Arenig interval. The palynological assemblages of Karakorum show a marked similarity to the cold water Peri‐Gondwana assemblages; i.e. to those of Li Jun's Arbusculidium‐Coryphidium‐Striatotheca‘Mediterranean’ Bioprovince. Biogeographical and geological comparisons suggest that, before the accretion of Cimmerian microplates to the Eurasian continent, the Karakorum Microplate was located along the northern margin of Gondwana in a latitude intermediate between the Mediterranean region and South China (Yangtze Platform).
Early Proterozoic regolith at Pasvik, NE Norway: palaeoenvironmental implications for the Baltic Shield
Authors: Sturt Brian A. , Melezhik Victor A. , Ramsay Donald M. 
Published: July 2007

ABSTRACTRegolith occurs at a number of localities along the northern margin of the early Proterozoic Pechenga Greenstone Belt marking a profound stratigraphic unconformity at the base of the 10 km thick Petsamo Supergroup. The age of regolith formation can be bracketed between 2.453 ± 42 Ga (Sm‐Nd) and 2.330 ± 36 Ga (Rb‐Sr). Regolith is developed on a varied substrate of Archaean rocks including early Proterozoic layered gabbros (2.45 Ga). The best example of the regolith occurs in the Pasvik valley at Brattli, Norway. Analogues are widespread on the Baltic Shield at the base of early Proterozoic ‘greenstone belts’ showing a low degree of chemical weathering and carbonatisation. Fluviatile deposits overlying the Brattli regolith preserve unweathered pyrite‐magnetite boulders and terrigenous pyrite grains. These features are considered to relate an arid or semi‐arid palaeoenvironment, possibly with some deficiency of oxygen in the atmosphere‐hydrosphere system. A systematic and well‐preserved regolith or palaeosaprolite at the base of the Petsamo Supergroup is proof that the northern boundary of the Pechenga Greenstone Belt is a fundamental first‐order unconformity. This places constraints on geotectonic modelling of this early Proterozoic rift‐basin.
THE IMPACT‐FLOOD CONNECTION: DOES IT EXIST?*
Authors: Deutsch Alexander , Koeberl Christian , Blum Joel D. , French Bevan M. , Glass Billy P. , Grieve Richard , Horn Peter , Jessberger Elmar K. , Kurat Gero , Reimold Wolf Uwe , Smit Jan , Stöffler Dieter , Taylor Stuart Ross 
Published: July 2007

ABSTRACTIn a recent article inTerra Nova, Kristan‐Tollmann and Tollmann (1994) suggested that the Biblical Flood can be explained by seven fragments of a comet that impacted the ocean at seven locations on Earth at 03.00h (C.E.T.) on 23 September, 9545 yr BP. We demonstrate that all the ‘geological proofs’ that allegedly support their conclusions are not supported by the available data on impact cratering. Their hypothesis is based on insufficient and ambiguous data, selective citation, and incomplete comprehension of previous research.
The geologist's dilemma: predicting the future behaviour of buried radioactive wastes
Authors: Chapman Neil A. 
Published: July 2007

ABSTRACTThe last 10–15 years have produced a considerable amount of research into the geological disposal of radioactive wastes. This has had some very beneficial spin‐offs for the geosciences. There are, however, a number of areas where it is difficult for earth scientists to provide quantitative information required for the types of long‐term safety assessment being performed at present. With the likely increased stringency with which we may begin to treat other industrial wastes, much is to be learned from the radioactive waste experience. This article reviews some of the geological issues in constraining long‐term predictions, discusses how geological data are used, and questions exactly what it is that we are trying to achieve in the management of these wastes and in the regulations concerning their disposal.
Geophysical interpretation of a high‐resolution seismic refraction profile in the Northern Apennines
Authors: Biella Giancarlo , De Franco Roberto , Demartin Martina , Barzaghi Riccardo , Sanso Fernando , Sguerso Domenico 
Published: July 2007

ABSTRACTA combined seismic and gravimetric interpretation in the Northern Apennines area (Italy) is presented. To the knowledge of the authors, this is one of the few attempts to apply tomographic methodology to a seismic refraction profile. This procedure, together with the classical interpretation for defining lower reflectors, led to the formulation of quite an accurate model of the upper crust. A gravity analysis was performed concurrently taking into account the seismic results at different depths which correspond to different frequency domains in the gravity signal. While the medium‐ and high‐frequency patterns have been solved by trial‐and‐error, the regional trend has been modelled applying the collocation procedure to the gravity data.