bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tectonic evolution of the North Aegean trough
Authors: Lybéris Nicolas 
Published: April 2008

Summary

Geological field data are used together with interpretation of Landsat images, results obtained during a
Jean Charcot
cruise in 1972, and other available seismic reflection profiles, to discuss the tectonic evolution of the North Aegean trough. This bathymetric trough is located over a narrow sedimentary basin with up to 6 km of sediment connected to two NNW-SSE sedimentary basins: the Thermaïkos and Kavala basins. The prevailing tectonic regime is extensional associated with strike-slip, with no evidence of compression as confirmed by seismo-tectonic observations. This regime has dominated the evolution of the North Aegean, as the prolongation of the North Anatolian fault since the Tortonian, However, the present eastern bathymetric trough does not have the same tectonic origin. The main extensional zone apparently lies to the north of it and continues eastward into the Thrace basin up to the Maritsa fault.
Rotational mechanisms of active deformation in Greece and Iran
Authors: Jackson James , McKenzie Dan 
Published: April 2008

Summary
The purpose of this paper is to emphasize the importance of vertical and horizontal rotations in the evolution of geological structures. In the Aegean region pervasive normal faulting, probably listric in nature, is responsible for substantial vertical rotation of footwall and hanging wall blocks as well as fault planes. The experience of the Basin and Range Province suggests that strain fields deduced from micro- or macro-structural analyses of fault planes in such an environment are unlikely to be correct unless the detailed 3-dimensional geometry of the motion on the largest faults is known. A particular hazard is the interpretation of rotated low angle gravity glides and high angle antithetic normal faults as thrusts and reverse faults respectively.
In northeast Iran, a combination of thrust and strike slip faulting has led to substantial horizontal rotations whose sense can only be deduced by a knowledge of the history of movement on major structures or by palaeomagnetism. In zones of major continental deformation present day strike azimuths, as well as horizontal and vertical directions, are of no particular significance, and the interpretation of even quite young structural data without a knowledge of the rotations involved may lead to incorrect geological reconstructions.
Listric normal faulting and the reconstruction of the synmetamorphic structural pile of the Cyclades
Authors: Ridley John 
Published: April 2008

Summary
There are late, post-metamorphic faults on the Aegean island of Syros that are demonstrably listric normal. Breccias associated with these faults are identical to those of late low-angle faults elsewhere on the island. It is therefore proposed that these low-angle faults are the toes of listric normal faults. This provides a basis for delineating a structural succession prior to faulting in which apparently ‘allochthonous’ rocks were originally at a higher level in the pile. This is consistent with the observed structural succession on Syros. The highest structural units are greenschists with similar kinematic axes to those of the blueschists below, but with a contrasting deformation style. These greenschists may have been derived from the ‘roof’ of the convergence zone in which the blueschist metamorphism took place.
Similar fault patterns can be inferred for many of the neighbouring islands, which are horst blocks. Many show peripheral ‘upper units’ of weakly- or non-metamorphic rocks. The ‘upper units’ are inferred to have been originally at a high level in a pile built up during early Tertiary tectonism and are not remnants of a far-travelled nappe emplaced in the Miocene.
On the Neogene development of the Eastern Mediterranean basins
Authors: Jasko S. 
Published: April 2008

Summary
The cauldron-like depressions of the Eastern Mediterranean, the Black Sea and the Southern Caspian differ from the foredeep basins of young fold-mountains of Neotectonic Europe in shape and form. The formation of these collapse structures has modified the palaeogeography of the Alpine-Carpathian-Balkan-Caucasus mountain system.
The deep basins of the Mediterranean formed in the south of Neotectonic Europe and on the margins of North Africa, probably at the beginning of the Pliocene. Subsidence of the Black Sea and of the Southern Caspian took place in the north of Neotectonic Europe and on the margin of the Russian platform in the Late Pliocene and Early Quarternary.
A Middle Miocene thermal event in northern Greece confirmed by coalification measurements
Authors: Chiotis E. D. 
Published: April 2008

Summary
An important thermal event is confirmed by vitrinite reflectivity measurements on coal samples from deep oil exploration wells in Kavala Bay and the Nestos delta, northern Greece. Only the lower depositional sequence of the Nestos Delta, to which a Middle Miocene age is attributed, has been affected. The coal bearing sediments have been heated to temperatures above 200°C at depths less than 2000 m. A plutonic intrusion east of the Nestos wells is postulated to have been the cause. The event corresponds in time to the well known episode of Middle Miocene local anatexis and acid plutonism in the central and southern Aegean area.
Loose-boundary hydraulics and fluid mechanics: selected advances since 1961
Authors: Allen J. R. L. 
Published: April 2008

Summary
A major and acknowledged role in the advance of sedimentological knowledge is played by the methods of physics as expressed through fluid mechanics and loose-boundary hydraulics. Turbulence is increasingly being seen as involving orderly flow structures, and these are significant for the origin of several sedimentary structures and for suspension transport. Recent advances in sediment-transport theory are rooted in the concept of the sediment load as a downward-acting force and in the notion of the flow as a transporting machine. Laboratory experiments are increasing our understanding of bedforms due to rivers and waves, but there is a need for well-framed field studies to clarify the influence of change in natural environments. Physical explanations are being proposed for tidal bedforms. Field studies in both modern environments and the stratigraphic record suggest that tidal patterns and strengths are recognizable from the internal features of cross-bedded units formed by sand waves. Tidal patterns are complex, however, and a wider range of situations needs to be explored than has hitherto been the case. Mathematical modelling could help to define the expectable bedding patterns. Although successful mathematical models have been constructed of flow and sedimentation in channel bends, secondary flow in real bends and the evolution of those bends are not yet well understood. Turbidity currents on a geologically significant scale have not been observed directly, but valuable insights into their character and processes have come from laboratory experiments. Recent laboratory work points to the limitations of lock-exchange experiments and emphasizes the various ways in which turbidity currents mix with the ambient medium. These studies seem to have implications, yet to be worked out, for the internal features and some sole marks of turbidites.
Facies analysis of volcaniclastic sediments: a review
Authors: Suthren R. J. 
Published: April 2008

Summary

A number of problems are encountered in the study and interpretation of sequences of volcaniclastics (sediments or sedimentary rocks composed predominantly of volcanic particles). These problems include the lack of modern analogues, the complex interaction of volcanic and sedimentary processes, and extensive diagenetic alteration. Volcaniclastic sediments are produced and emplaced by
autoclastic
(mechanical breakage during magma movement),
hydroclastic
(water/magma interaction),
pyroclastic
(magmatic explosion) and
epiclastic
(sedimentary erosion, transport and deposition) processes, or by any combination of these. The systematic study of lithology, texture and primary structure sequences, and their lateral and vertical variations, is leading to the erection of facies models for recent volcaniclastics. These models are likely to have important applications in the interpretation of ancient sequences of volcaniclastic sedimentary rocks, as well as practical applications in mineral and petroleum exploration and volcano prediction.
Shortening of continental lithosphere: the neotectonics of Eastern Anatolia — a young collision zone
Authors: Dewey J.F. , Hempton M.R. , Kidd W.S.F. , Saroglu F. , Şengör A.M.C. 
Published: April 2008

Summary
We use the tectonics of Eastern Anatolia to exemplify many of the different aspects of collision tectonics, namely the formation of plateaux, thrust belts, foreland flexures, widespread foreland/hinterland deformation zones and orogenic collapse/distension zones. Eastern Anatolia is a 2 km high plateau bounded to the S by the southward-verging Bitlis Thrust Zone and to the N by the Pontide/Minor Caucasus Zone. It has developed as the surface expression of a zone of progressively thickening crust beginning about 12 Ma in the medial Miocene and has resulted from the squeezing and shortening of Eastern Anatolia between the Arabian and European Plates following the Serravallian demise of the last oceanic or quasioceanic tract between Arabia and Eurasia. Thickening of the crust to about 52 km has been accompanied by major strike-slip faulting on the right-lateral N Anatolian Transform Fault (NATF) and the left-lateral E Anatolian Transform Fault (EATF) which approximately bound an Anatolian Wedge that is being driven westwards to override the oceanic lithosphere of the Mediterranean along subduction zones from Cephalonia to Crete, and Rhodes to Cyprus. This neotectonic regime began about 12 Ma in Late Serravallian times with uplift from wide-spread littoral/neritic marine conditions to open seasonal wooded savanna with colluvial, fluvial and limnic environments, and the deposition of the thick Tortonian Kythrean Flysch in the Eastern Mediterranean. Earthquake hypocentres are scattered throughout the region but large earthquakes are concentrated mainly on the major faults and are mostly shallow, supporting the idea of a brittle elastic lid with hypocentres concentrated towards its base with more ductile deformation in the middle and lower crust. Neotectonic magmatic suites are nepheline-hypersthene normative alkali basalts of mantle origin, and silicic/intermediate/mafic calcalkaline suites, both suites occurring in pull-apart basins in strike-slip regimes and along N-S extensional fissures, and both suites showing a strong change to central activity in the Pliocene. Upper-crustal strains appear to be discontinuous in space and time, with zones of strong shortening representing shoaling of crustal detachment zones flattening between 5 and 10 km. Approximately NW- (dextral) and NE- (sinistral) trending lineaments bound less deformed wedges (low relief seismically ‘dead’ areas) and vary from simple strike-slip faults to complicated braided transform-flake boundaries with pull-apart and compressional segments (N and E Anatolian Transform Faults). Volcanoes lie in grabens on N-S ‘cracks’ that extend into the Arabian Foreland and in transcurrent pull-aparts. Major extensional basins lie at plate (Adana) and flake (Karliova) triple junctions and result from compatibility problems.
Garnet, tourmaline and muscovite-bearing leucogranites, gneisses and migmatites of the Higher Himalayas from Zanskar, Kulu, Lahoul and Kashmir
Authors: Searle M. P. , Fryer B. J. 
Published: April 2008

Summary

Approximately 30–50% of the map area of the Central Crystalline Complex of the Higher Himalayas in Zanskar, Kulu, Lahoul and Kishtwar-Kashmir (NW India) is composed of Miocene leucogranites intruding metamorphic basement rocks. Ultrametamorphism at deeper crustal levels resulted in
in situ
anatexis, migmitization and
lit-par-lit
intrusions or stromatic layering within high-grade metasedimentary rocks. Garnet, tourmaline and muscovite-bearing granites locally contain biotite, apatite or kyanite.

Leucogranites at higher crustal levels are associated with a widespread network of anastomosing dykes and sills with high tourmaline content. Rare-earth-element (REE) abundances are relatively low. Garnets are compositionally variable and are usually unzoned.

Extremely high
87
Sr/
86
Sr initial ratios of leucogranites (0.755–0.769) indicate a crustal anatectic origin while the wide range of Sr initial ratios can be explained by melting of a variety of metasedimentary rocks of the subducting Indian Shield.

Radiometric ages of Himalayan leucogranites (28–12 Ma) follow closely in time a thermal peak of metamorphism (40–25 Ma). Inversion of metamorphic isograds during large-scale crustal subduction along several major thrust zones in the Higher Himalayas followed immediately after generation of the leucogranites. The leucogranites are interpreted as anatectic melts of high-grade metamorphic crystalline basement, generated at depth by residual (Barrovian) heat with a large amount of volatile and fluid flux. Frictional heating along the N-dipping Main Central Thrust is not considered a major source of heat for generation of the leucogranites.
The Alps: a case of multiple collision
Authors: Hunziker J. C. 
Published: April 2008

Summary
The numerous isotopic data accumulated during the last decade throughout the Western Alps, make it tempting to draw a picture of polyphase Alpine tectono-metamorphic history constrained by these data. Gabbroic precursors of the Mesozoic Piémont ophiolites in the Dent Blanche Nappe, point to a thinning of the continental crust by the beginning of the Triassic. Biotite cooling ages of ∼ 180 Ma, in the Valpelline-IIDK-Ivrea Unit, set an older limit to the beginning of Alpine nappe emplacement. The younger limit is given by Cretaceous ages on high-pressure paragenesis in the Sesia basement and the Piémont ophiolites. In both, this first eo-Alpine tectono-metamorphic cycle was overprinted by an Eocene-Oligocene greenschist-facies metamorphism and a recumbent schistosity. Miocene mica cooling ages, as well as apatite fission track ages, can be linked to the Miocene décollement and ‘rétrocharriage’ phase in the Western Alps, followed by isostatic re-equilibration and denudation.
The NW external Alpine Thrust Belt and its implications for the geometry of the Western Alpine Orogen
Authors: Butler R. W. H. , Matthews S. J. , Parish M. 
Published: April 2008

Summary
The NW external Alpine Thrust Belt contains an imbricated basement—cover sequence which is broadly continuous with the French cratonic foreland. This thrust belt developed in the late stages of Alpine orogenesis and carried the previously deformed and metamorphosed internal zones to the WNW, piggy-back fashion, onto the French Craton. Balanced cross-sections restore the thrust-belt structures to lie for over 100 km to the ESE of their present, innermost outcrop trace. The regional sole thrust commonly lies in the upper crust. To acheive a balance between different crustal levels requires a layer of lower crust, on which the external zones originally lay, to underlie the entire present outcrop width of the Alps. Therefore models of Alpine orogenesis, which require the internal zones to be underlain by their deep crustal root, are not valid and new models are required to explain the sub-surface geometry of the NW Alps. This paper stresses the importance of resolving the external parts of orogens, particularly using balanced cross-sections, before attempting to either interpret the internal parts of orogenic belts or make palaeogeographical reconstructions.
Palaeomagnetism and continental collision in the Alpine Belt and the formation of late-tectonic extensional basins
Authors: Channell James E. T. 
Published: April 2008

Summary
New palaeomagnetic data are consistent with the hypothesis that Adria moved as a promontory of the African Plate during the Mesozoic. This hypothesis is supported by regional facies analysis and by geophysical data from the eastern Mediterranean basins which indicate a continental lithosphere. However, the new data cast doubt upon the concept of a rigid, autochthonous African promontory remaining coherent during Alpine deformation. It is apparent that small-scale relative rotations have occurred during the Tertiary in areas which were previously considered authochtonous. Late-tectonic extensional basins, such as the Tyrrhenian Sea, are superimposed on the continent-continent collision suture and their growth is contemporaneous with thrusting in surrounding arcs. The very rapid evolution of the collision suture into a region of extension is due to a rapid lithospheric thinning process, such as catastrophic delamination of part of the mantle lithosphere. Such delamination would be most likely to occur very soon after a collision involving fast lithospheric thickening.
Collision tectonics in the Scandinavian Caledonides
Authors: Hossack J. R. , Cooper M. A. 
Published: April 2008

Summary
The Scandinavian Caledonides provide a well-exposed example of a deeply eroded orogen. The pre-erosion thrust front is located much farther to the E than previously supposed, the only true autochthon being S of Oslo. The external zone of the orogen is divided into three series of thrust sheets; the Baltic Cover Sheets, the Crystalline Thrust Sheets and the Oceanic Thrust Sheets. The three thrust sheet complexes are derived from widely different provenances but display all the characteristics of a classic fold and thrust belt. Sections through the external zone can be balanced and restored, indicating large amounts of translation southeastwards onto the Baltic Craton. The internal zone is composed of a number of tectonostratigraphic disparate units which display a ductile style of deformation. Sections through the internal zone are not restorable and assemblage in a large-scale shear zone is proposed, followed by thrusting onto the Baltic Craton. Deformation in the orogen occurred throughout a period of ∼ 100 Ma starting in the Late Cambrian. Thrust vectors for the orogen display rotation with time and are generally oblique to the Caledonian Front; within the internal zone stretching lineations are parallel to orogenic strike. A collision model for the orogen includes two W-dipping subduction zones, oblique collision producing shear parallel to the orogen and oblique thrust-sheet motions culminating in the large-scale underthrusting of the Laurentian Craton by the Baltic Craton.
On the anisograptid affiliation of
‘Dictyonema’ flabelliforme
(Eichwald 1840) and its nomenclatural consequences
Authors: Erdtmann Bernd-Dietrich 
Published: April 2008

Summary

The recent discovery of
Radiograptus
stratigraphically below a series of morphological predecessors to the planktic siculate
‘Dictyonema’ flabelliforme-sociale
groups suggests a phyletic derivation of these forms from the anisograptid
Radiograptus
(Bulman 1950) and thus requires a taxonomic revision of the planktic species of
Dictyonema
. The type species of
Dictyonema, D. retiforme
(Hall 1843), is a Silurian sessile benthic member of the family Dendrograptidae. The genus
Dictyonema
must be restricted to represent the approximately 140 sessile species of cone-shaped, dissepimentous, dendroid graptolites (upper Cambrian-Carboniferous), whereas the homeomorphic planktic forms, now belonging to the family Anisograptidae, require a new generic name. The names
Rhabdinopora
(Eichwald 1855),
Graptopora
(Salter 1858) and
Dictyograptus
(Hopkinson & Lapworth 1875) are valid
nomina oblita
for this group of graptolites, with
Rhabdinopora
having priority.
Dictyograptus
would be a much favoured alternative name because of its long historical application to the ‘
flabelliforme-sociale
group’ and its euphonic semblance to
Dictyonema
, but being a junior name, its preference over
Rhabdinopora
would require suppression of the rule of Priority and is not recommended. The history of the generic status of
Rhabdinopora flabelliformis
(Eichwald 1840) and of
R. socialis
(Salter 1858) is briefly reviewed.
Biostratigraphic integration of Ordovician graptolite and conodont zones—a regional review
Authors: Bergström Stig M. 
Published: April 2008

Summary
Graptolite and conodont zonal successions, each currently including about fifteen zones, serve as the principal bases for regional correlations within the Ordovician System. Zonal graptolites and conodonts are not commonly found together but recent work in Baltoscandia, North America, and other areas has made it possible to establish more than eighty levels of ties between graptolite and conodont zonal units. Most of these are in strata of Arenig, Llanvirn, and Llandeilo age; relatively fewer ties have been found in other parts of the system. A regional evaluation of graptolite/conodont zone relations has produced useful new information not only about correlation between standard graptolite and conodont zones, but also, indirectly, about relations between units in the graptolite-zone successions of the European and Pacific Provinces.
Astogenetic development of some lower Ordovician graptolites from Norway
Authors: Spjeldnaes Nils 
Published: April 2008

Summary

The variation of taxonomically important characters commonly used in the classification of lower Ordovician graptolites has been studied in fairly large populations of
Extensograptus ‘slemmestadi’
and
‘Trochograptus’ diffusus
from the lower Ordovician of the Oslo Region, Norway. In
Extensograptus ‘slemmestadi’
, which belongs to the
patulus-hirundo
lineage, there is a good correlation between ontogeny and supposed phylogeny, but some of the commonly used taxonomic characters are not as useful as previously supposed. An astogenetic series of
‘Trochograptus’ diffusus
shows that it started as a
Tetragraptus
stage, then acquired secondary, lateral branching, (
Schizograptus
stage), and passed through a
Trochograptus
stage before the rare, large specimens reached a
Holograptus
stage. In both species, the preserved population is—as is usual in marine invertebrates—dominated by small, young specimens in which important taxonomic characters have not been developed.
On the morphological characteristics of the
spiralis
group and the stratigraphic significance of the appearance of
Cyrtograptus
Authors: Deng Bao 
Published: April 2008

Summary

The paper deals with the late Llandovery and early Wenlock
Cyrtograptus
and
M. spiralis
group discovered in Ziyand, Shaanxi. Both the appearance of
Cyrtograptus
and the morphological characteristics of the
spiralis
group are stratigraphically significant. According to the mode of preservation of the
spiralis
group, the rhabdosome is thin or elongated along its proximal parts. Sometimes the proximal part is closely coiled into a perfectly regular or an irregular planospiral shape. Distally it is coiled, arcuate, straight or irregular. The proximal thecae are small, gradually becoming larger towards the distal end. All thecae are subtriangular in form. Associates of the
spiralis
group include
Cyrtograptus lapworthi, C.
cf.
laqueus, C. shishkaticus
and other genera such as
Sinostomatograptus, Stomatograptus. C. centrifugus, C.
sp. (cf.
C. graphicus
Golikov) occur at a higher horizon. According to the analysis of the specimens, speculation on the affinities between
Cyrtograptus
and the
spiralis
group is made and the possibility of evolution from
spiralis
to
Cyrtograptus
suggested. These evolutionary changes can be used to subdivide stratigraphic units. It is suggested that the first appearance of
Cyrtograptus
should be regarded as the lower boundary of the middle Silurian.