bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cretaceous to Neogene structural evolution of the Lampedusa Shelf (Pelagian Sea, Central Mediterranean)
Authors: Torelli Luigi , Grasso Mario , Mazzoldi Glauco , Peis Davide , Gori Davide 
Published: July 2007

ABSTRACTStudies of multichannel seismic reflection profiles, calibrated with borehole data, have been carried out in the Tunisian shelf surrounding the islands of Lampione and Lampedusa, in order to define the Mesozoic‐Cenozoic stratigraphie and structural evolution of this sector of the Pelagian foreland. The stratigraphy and subsidence history show a subsiding Upper Jurassic carbonate platform buried, by syn‐ and post‐rift neritic to deep marine siliciclastics, marls and limestones of Neocomian‐early Eocene age. Thick Middle‐Upper Eocene shallow‐water carbonates (Halk el Menzel Fm.), lie unconformably over the deep‐water sediments and exhibit progradational geometries.Messinian evaporites are confined to the deepest parts of the Neogene basins and Plio‐Quaternary sediments are widespread over the area. Several unconformities affect the stratigraphic column and have been interpreted as related to compressive events during Late Cretaceous‐early Tertiary times. These compressive events produced uplift, folding and reverse faulting, trending about NW‐SE and partly reactivating Lower Cretaceous extensional structures. The uppermost regional unconformity indicates widespread emergence and erosion during Oligocene and Miocene tintes and was probably related to a younger compressional phase. A strong Upper Miocene‐Quaternary extension event also affected the area, characterized by WNW‐ESE trending normal faults, parallel to faults flanking the main grabens of the Sicily Strait rift zone. Since the Messinian, the structural evolution of the area has been controlled by rift‐related processes which triggered crustal extension in the Pelagian foreland.
Study of the Messinian carbonate‐evaporite lithofacies offshore Western Libya
Authors: Mriheel Ibrahim Y. , Alhnaish Abdelhakim S. 
Published: July 2007

ABSTRACTThis study represents a preliminary investigation of the late Messinian subsurface Marsa Zouaghah Formation in the Western Libyan Offshore, Central Mediterranean Sea. The formation was deposited in three major environmental settings: (a) Marginal Sabkha; (b) Open Lagoon; and (c) Hypersaline Lagoon. The marginal sabkha and open lagoonal settings are locally interrupted by intertidal oolitic shoal deposits. The marginal sabkha facies is replaced in central parts of the Libyan offshore by a narrow zone of aeolian‐fluvial facies, the distribution and thickness of which is entirely controlled by a local uplift, the Tripoli Nose'. The marginal sabkha facies broadly defines the late Messinian palaeoshoreline lying parallel to, and north of, the E‐W Jifarah fault system which dominated the southern part of the Libyan offshore. This fades is, thus, interpreted as being structurally controlled by fault systems. The hypersaline lagoonal facies is developed in areas of relatively higher rates of subsidence than that of adjacent facies belts. It is therefore, related to restriction formed by continuous subsidence and evaporation. The Marsa Zouaghah Formation constitutes saltern evaporates deposited over a wide platform in sabkha and lagoonal settings, forming part of the ‘basin‐wide‐evaporites’ of the Mediterranean Basin deposited during the Messinian salinity crisis. The evaporites formed during a major relative sea‐level fall within a subsiding basin situated on the northern continental margin of the African plate. Local, vertical and lateral variations in lithofacies and thickness within the Messinian deposits of the north‐west Libyan offshore were controlled by contemporaneous strike‐slip movements in addition to sea‐level change.
Hydrothermal sedimentation in the caldera of Santorini, Hellenic Volcanic Arc
Authors: Cronan D.S. , Varnavas S. , Perissoratis C. 
Published: July 2007

ABSTRACTSediments in the caldera of Santorini are receiving a hydrothermal input of iron and manganese from presently active hydrothermal vents off the Kameni Islands, and are enriched in these elements in their surface layer. However, greater Fe‐Mn enrichments occur in discrete layers at depth in the cores separated from the surface by Fe‐Mn poor sediments, suggesting that a past hydrothermal event may have been more intense than the present one. The buried Fe‐Mn enriched layers occur above a turbidite thought to have resulted from sediment slumping due to a major volcanic eruption and earthquake in 1650, and are thought to have formed consequent on the activation of faults related to the magma chamber by the eruption facilitating seawater‐rock interaction processes and the formation of metal‐rich hydrothermal solutions.
Ocean's philosophical images
Authors: Givone Sergio 
Published: July 2007

ABSTRACTFrom early Greek cosmology and pre‐socratic thought to Kant, Nietzsche and the philosophy of existence, ‘ocean’ is a figure of the most relevant significance, in accordance with two different patterns: as mythical representation of the principle of the universe and as metaphor of the adventure of human knowledge. Now the question could be: do the philosophical images of the ocean have some value for modern science?
The bottom of the ocean: three abysses
Authors: Nievo Stanislao 
Published: July 2007

ABSTRACTThis testimony is the result – better, the tale – of some sea and ocean descents made by a novelist to gather information for writing two of his books. The first one is The meadow under the sea published by Mondadori, 1974, and thereafter in various other editions, in Italian and other languages. The second is The Blue Whale, Mondadori, 1988, which went through several Italian editions.The present piece concerns impressions and events of contacts with the marine and oceanic floor in the Mediterranean sea, along Atlantic beaches and the Indian Ocean, off Tromelin, Madagascar.The last voyage takes the novelist to a peculiar situation, where water's darkness overturns the image, comes through the bathysphere port‐hole and the observer looks inside himself, a view that corresponds to a mythical history of the ocean floor.
Two revolutions in the Earth Sciences
Authors: Emiliani Cesare 
Published: July 2007

ABSTRACTTwo great revolutions have shaken the field of the geological sciences since World War II, one involving the solid Earth and the other involving the ice ages. The former came after a long and gradual preparation that extended across a century. The latter came abruptly, after a long period of stasis during which little conceptually new had emerged. The former did not demolish anything ‐ it was only the logical conclusion of a long process of discovery. The latter demolished a canon that had become a dogma held true for half a century. The reactions of the scientists to the two revolutions are a study in contrast: instant acceptance of the former versus laggard and reluctant acceptance of the latter.
Plate tectonics at Lamont: the first year‐1966
Authors: Pitman Walter , Bonatti E. , Wezel F. C. 
Published: July 2007

ABSTRACTDuring the period from the mid 1950s to the 1960s it seemed as if the community of earth scientists was slowly being dragged toward accepting continental drift. But resistance was often steadfast. Each new ideal or set of data produced a trickle of new converts, but also generated heated debate. The concept of sea‐floor spreading and the corollary hypothesis that the process of spreading would generate a set of symmetrical magnetic anomalies was particularly disputatious. The discovery of the Eltanin 19 magnetic anomaly profile ended the dispute and the trickle became a flood.
Definition and global correlation of the Santonian‐Campanian boundary
Authors: Gale A.S. , Montgomery P. , Kennedy W.J. , Hancock J.M. , Burnett J.A. , McArthur J.M. 
Published: July 2007

ABSTRACTReview of biostratigraphical evidence from different regions shows that criteria used by workers on various marine fossil groups to define the Santonian‐Campanian boundary differ considerably in relative age and position. Probably the most widely recognizable of these criteria is the extinction of the distinctive crinoid Marsupites testudinarius (North America, Europe, Asia, north Africa, Australia), which, coincides exactly with two separate definitions of the boundary ‐ appearances of the ammonite Placenticeras bidorsatum and the belemnite Gonioteuthis granulataquadrata ‐ and may also coincide with a third ‐ entry of the planktic foraminiferan Globotruncana elevata. A comparison of evidence from upper Santonian and lower Campanian successions in widely separated regions allows us to place a series of important biostratigraphical markers in correct order. Defining the boundary at the extinction of M. testudinarius corresponds to a 87Sr/86Sr of 0.707479, and a small positive excursion in δ13C. The base of magnetochron 33R, generally considered to coincide with, or fall just above the base of the Campanian, is shown to lie within the upper Santonian Uintacrinus socialis Zone.
Holocene soil chronoassociation in part of the Middle Gangetic Plain: morphological and micromorphological characteristics
Authors: Mohindra Rakesh 
Published: July 2007

ABSTRACTSystematic variations in soil characteristics related to degree of soil profile development in part of the Middle Gangetic Plain suggest a soil chronoassociation similar to the soil chronosequences observed on some river terrace formed by tectonic uplift. This chronoassociation has five members QG1 to QG5, the youngest being QG1 (< 500 yr BP). Variations in degree of horizon differentiation, profile thickness, clay accumulation, plasma separation, argillan thickness, weathering stage and day mineralogy have been used to determine the degree of soil development.Pedogenic processes active in these soils are decalcification, translocation of clay, sesquioxide and organic matter, plasma separation and weathering of minerals. The amount and variability of clay minerals are significantly related to the type and duration of pedogenesis in different parts of the area. The oldest soils with pedogenic calcite (10 000 yr BP) developed during a dry period. Since 8000 yr BP climatic conditions of higher rainfall and better drainage have prevailed in the area.Neotectonic movements have tilted the Gandak megafan block and have caused shifting of the Gandak river to the east about 105 km from its original course, leaving behind numerous channels, ponds, lakes and other features of impeded drainage.
Alkali feldspars as a main phosphorus reservoirs in rare‐metal granites: three examples from the Bohemian Massif (Czech Republic)
Authors: Frýda J. , Breiter K. 
Published: July 2007

ABSTRACTPhosphorus‐rich alkali feldspars were found in three peraluminous highly differentiated albite‐topaz‐Li‐mica granites in the W and S parts of the Bohemian Massif. The average contents of P2O5 in K‐feldspars (Křížovy kámen 0.57 wt%, Homolka 0.77 wt%, and Podlesí 0.83 wt%) are higher than the average contents of P2O5 in albites (Křížovy kámen 0.23 wt%, Homolka 0.23 wt%, and Podlesí 0.39 wt%). The analyses of feldspars indicate that partition coefficient of phosphorus between K‐feldspar and albite range from 1.5 to 2.5. Measured data in K‐feldspars suggest a statistically significant difference from the Al3++P5+=2 Si4+ substitution mechanism for higher phosphorus concentration. The P‐content in K‐feldspars from the Podlesí‐granite represent the highest P‐content in natural feldspar known to date (up to 2.5 wt% of P2O5)‐ It is suggested that all studied granites retained nearly all phosphorus of granitic melts and that their alkali feldspars represent major reservoirs of phosphorus.
Determination of uranium, thorium and potassium contents in rock and soil samples using low‐energy gamma ray spectrometry
Authors: Reddy A. Subjender , Rao N. Venkat 
Published: July 2007

ABSTRACTA low‐energy gamma ray spectrometric set‐up for determination of uranium, thorium and potassium in rock and soil samples is described. The procedure described exploits the fact that a large proportion of gamma quanta produced in the Th and U decay series have energies of less than 1 MeV. The instrumental parameters such as sensitivity and detection limits for the low‐energy region have been studied. The measuring conditions were optimized by suitably minimizing the background and by increasing the overall sensitivity with the help of proper geometry of measurement and sample parameters. High sensitivity and low detection limits for U and Th can be achieved using low‐energy gamma ray spectrometry. The method provides a rapid analysis with a counting time of the order of a few minutes for each sample.
A high‐velocity layer in the lower crust of the North German Basin
Authors: Rabbel W. , Förste K. , Schulze A. , Bittner R. , Röhl J. , Reichert J.C. 
Published: July 2007

ABSTRACTA network of deep seismic refraction profiles in Northern Germany consisting of parts of the European Geotraverse (EGT) and additional new Unes is interpreted. The most striking result is the proof of an approximately 10 km thick high‐velocity layer in the lower crust. Its P‐wave velocity of 6.9‐7.5 km s−1 is typical for shield crusts or lower crust in extensional environments intruded by mafic magma. The layer is observed in an area of roughly 150 × 180 km north of the Elbe river and seems to continue north‐east, at least up to the Caledonian deformation front at the southern edge of the Ringkøbing‐Fyn High. It correlates spatially with an area of high positive gravity anomalies. Here, a Moho topography of several kilometres, which had already been postulated on the basis of gravity inversions and sporadic near‐vertical PMP reflections, could be confirmed by the interpretation of seismic wide‐angle records. The termination of the high‐velocity lower crust at the Lower Elbe Lineament, which strikes parallel to the Teisseyre‐Tornquist Zone, contributes to its definition as a major lineament in the context of central European tectonics.
Optical parameters of maturity of organic matter dispersed in sediments: first results from the Central Apennines (Italy)
Authors: Corrado Sveva 
Published: July 2007

ABSTRACTLevels of organic maturity of Mesozoic and Tertiary sequences outcropping in the Central Apennines have been established, using vitrinite reflectance techniques, the Thermal Alteration Index and fluorescence colours of organic matter dispersed in sediments. These results provide new constraints throughout the Meso‐Cenozoic evolution of this crustal sector. In exploration geology, vitrinite reflectance provides data on hydrocarbon maturation by constraining organic matter maturity. In sedimentary basin modelling, it is adopted to define the palaeothermal regime. Vitrinite reflectance (Ro) also provides information on the burial history of sedimentary basins and may be employed to estimate tectonic uplift and erosion rates. Thermal Alteration Index (TAI) and fluorescence colour values can be correlated with Ro and may be used to estimate the degree of maturation when vitrinite is absent.Samples derived from the Sabini and Tiburtini Mts, in slope facies between the Latium–Abruzzi carbonate Platform and the Umbria–Marche pelagic Basin; from the Simbruini and Ernici Mts, in carbonate Platform facies, and from upper Miocene turbiditic deposits outcropping between the Olevano–Antrodoco Une, towards the West, and the Marsica slope facies, towards the East. Both the pre‐terrigenous Meso‐Cenozoic sequences show a low grade of organic maturity: the Sabini and Tiburtini Mts show Ro values that are less than 0.4%, and the Simbruini–Ernici Range show Ro values that range between 0.5% and 0.65%. Field analysis indicates that the cause of these low maturity levels is that thick sequences of turbidites were never deposited during the Neogene evolution of the Apennine thrust belt. Moreover, Upper Miocene turbiditic deposits also show low maturity levels, with Ro values that are less than 0.5%, indicating that these deposits were never overthrusted by huge volumes of rocks, during the chain building. The slight increase in the maturity level recorded in the Marsica area may be related to local heating along shear zones in areas of strike‐slip tectonics.
Estimating the carbon transfer between the ocean, atmosphere and the terrestrial biosphere since the last glacial maximum
Authors: Maslin M.A. , Adams J. , Thomas E. , Faure H. , Haines‐Young R. 
Published: July 2007

ABSTRACTCarbon dioxide records from polar ice cores and marine ocean sediments indicate that the last glacial maximum (LGM) atmosphere CO2 content was 80–90 ppm lower than the mid‐Holocene. This represents a transfer of over 160 GtC into the atmosphere since the LGM. Palaeovegetation studies suggest that up to 1350 GtC was transferred from the oceans to the terrestrial biosphere at the end of the last glacial. Evidence from carbon isotopes in deep sea sediments, however, indicates a smaller shift of between 400 and 700 GtC. To understand the functioning of the carbon cycle this apparent discrepancy needs to be resolved. Thus, older data have been reassessed, new data provided and the potential errors of both methods estimated. New estimates of the expansion of terrestrial biomass between the LGM and mid‐Holocene are 700 GtC ± > 300 GtC, using the ocean carbon isotope‐based method, compared with of 1100 GtC ± > 500 GtC using the palaeovegetation estimate. If these estimates of the carbon shift to the terrestrial biosphere are equilibrated with the dissolved carbon in the oceans, and the CaCO3 compensation of the ocean is taken into account, then the glacial atmospheric CO2 would have been between 50 (± 30) ppm and 95 (± 50) ppm higher. The glacial atmosphere therefore should have had a CO2 partial pressure of between 330 and 375 μatm. Hence, a rise of between 130 and 175 μatm in atmospheric CO2, rather than 80 μatm, at the end of the last glacial must be accounted for.
Application of the chlorine‐36 method for the characterization of the groundwater circulation in tectonically active areas: examples from northwestern Anatolia/Turkey
Authors: Balderer W. , Synal H.‐A. 
Published: July 2007

ABSTRACTFor groundwaters of tectonic active regions the problem of determining the residence time above the range of the tritium method arises. The usually applied isotope techniques are often not appropriate because of (i) the high amount of water‐rock interaction, (ii) the underground production of nuclides in crystalline fissured rocks under geothermal conditions, (iii) the occurrence of highly saline waters at boiling temperature affected by waterrock interaction processes, as also the high fluxes of CO2. However, the 36Cl evolution will be affected by these processes, too. Nevertheless it gives an independent tool to investigate the groundwater evolution. Therefore the application of the 36Cl method looks very promising. Within this publication the interpretation of 36Cl measurements of three study areas along the North Anatolian Fault zone (from East to West) of Kuzuluk/Adapazari, Bursa and of Canakkale (Tuzla/Kestanbol) are discussed. By considering for each area the sources of 36Cl and the water‐rock interaction with respect to the chloride cycle, information on the ongoing processes of groundwater circulation and evolution have been derived. In addition, ranges of residence times of these waters were gained which are compatible with the results of geological, hydrogeological and hydrochemical investigations (Balderer et al., 1991; Greber, 1992, 1994; lmbach, 1992, 1994; Imbach and Balderer, 1990; Mutzenberg, 1989) as well as with already developed conceptual groundwater flow models.
Long‐term (105) or short‐term (103) δ13C excursion near the Palaeocene‐Eocene transition: evidence from the Tethys
Authors: Lu Gangyi , Keller Gerta , Adatte Thierry , Ortiz Nieves , Molina Eustoquio 
Published: July 2007

ABSTRACTExpanded sedimentary records from the Tethys reveal unique faunal and isotopic changes across the Palaeocene‐Eocene (P‐E) transition. Unlike in the open oceans, the Tethys exhibits a gradual decrease of 1.5% in δ13C values prior to the rapid δ13C excursion. Associated with the 613C excursion is a decrease in calcite burial, increase in detrital content and appearance of a unique opportunistic planktic foraminifera1 assemblage (e.g. compressed acarininids). The existence of a prelude decrease in δ13C values in the Tethys suggests that the P‐E δ13C excursion may have occurred in two steps and over a few hundred thousand years, rather than as one step over a few thousand years as previously suggested. This slower excursion rate is readily explained by changing organic carbon weathering or burial rates and avoids the need of invoking ad hoc scenarios.
Field examples of variations in fault patterns at different scales
Authors: Peacock D.C.P. 
Published: July 2007

ABSTRACTThree field examples are presented which show changes in fault patterns at different scales. Normal faults in Jurassic limestones in Somerset consist of zones of sub‐parallel segments at the exposure‐scale, but contain complex zones of brecciation at the decimetre‐scale. Normal faults in chalk at Flamborough Head consist of a complex network of small faults which accommodate strain between a set of large faults. The different‐sized faults at Flamborough Head have different geometries and histories, with the larger faults showing a phase of reverse reactivation. The faulting in the Sydney Basin, Australia, can be explained in terms of the evolution and reactivation of transfer zones between overstepping faults. These transfer zones can cause the deformation to appear to be more complex as the analysis becomes more detailed.Much recent work on the scaling relationslups of faults assumes that self‐similar fault patterns occur over a wide range of scales. The data presented in this paper, however, suggest that there are problems in using the deformation pattern at one scale to infer deformation at other scales. Ideally, any analysis should involve the study of a wide range of scales to overcome these problems.
Syn‐metamorphic nappe complex in the Rhodope Massif. Structure and kinematics
Authors: Burg Jean‐Pierre , Ricou Luc‐Emmanuel , Ivano Zivko , Godfriaux Ivan , Dimov Dimo , Klain Laslo 
Published: July 2007

ABSTRACTMylonitic gneisses of the Bulgarian and Greek Rhodope were deformed under medium pressure‐type metamorphism. The kinematic information contained in these gneisses shows that shear‐deformation occurred during development of a nappe complex. Lithologies and metamorphic histories allow a lower (footwall) and an upper (hanging wall) terrane to be distinguished that define a crustal‐scale duplex. As oceanic crust is involved, collision between two continental units with subsequent crustal thickening is inferred. The blocks would be Moesia to the north, and the Lower‐Rhodope promontory to the south, which collided in the Mesozoic to early Cenozoic. The nappe complex is characterized by south to southwestward (foreland directed) piling‐up and is associated with both coeval and subsequent extension. The late extension is associated with the establishment of a high temperature‐low pressure metamorphic gradient and plutonism that predates, but makes a transition to, the lithospheric extension of the Aegean Arc.