bluuebunny/crossref_metadata_2025 huggingface dataset:
Fluid velocity fields in 2D heterogeneous porous media: empirical measurement and validation of numerical prediction
Authors: Cassidy Rachel , MccLoskey John , Morrow Philip
Published: April 2008

The scale invariance of geological material and the consequent absence of a length scale on which to base the upscaling of measurements made on geological samples represent a serious challenge to the prediction of fluid behaviour in rock at economically interesting scales. Numerical simulation is an important tool for understanding constraints in this problem and current discrete fluid models in which complex boundary conditions can be represented have the potential for testing many possible upscaling schemes. At present, however, there are no accurate empirical data on the distributions of fluid velocities in complex, scale-invariant geometries, with which to validate such models.

To address this, fluid velocity fields in complex 2D media with fractal heterogeneity were measured. Digital models of rock geometries were created and translated into physical form using electric discharge machining and stereolithography. These physical models were then enclosed between parallel sheets of glass and Perspex forming a Hele-Shaw cell which was permeated with water, doped with small neutrally buoyant spheres and pumped at accurately steady and reproducible velocities. Local velocity vectors were estimated by the analysis of sequential images captured using high-resolution video. Precision digital control systems were used to move the cell relative to the camera and repeated measurements allowed the construction of full 2D velocity fields. The accuracy of the technique was assessed by comparison between automated and manual measurements, confirming the accuracy over approaching three orders of magnitude in velocity.

The results have been compared to the output of lattice Boltzmann (LB) simulations of flow in identical geometries, showing that the correlation between simulated and measured velocity fields is strongly dependent on the viscosity used in the numerical simulation. In particular, the LB scheme used in these tests is incapable of simulating correct viscosities for complex geometries. Some important effects are shown to be strongly viscosity dependent and it is concluded that some simulations may be able to predict the behaviour of high viscosity fluids only. Nonlinear effects between fracture and matrix flow are likely to be more important in these cases.
Sustainable small-scale gold mining in Ghana: setting and strategies for sustainability
Authors: Eshun P. A.
Published: April 2008

In Ghana, small-scale/artisanal gold mining has been on-going for more than a century. Artisanal mining has been the support for the rural people who more often than not are forced to sacrifice their farmlands and means of livelihood for large-scale mining operations. In order to reduce the activity of small scale/artisanal during the colonial era, laws were passed to bar indigenous operators from dealing in gold ore, amalgam, bullion, retorted gold, slags, concentrates and mercury. In recent years, however, under the auspices of the German non-governmental agency,
Gesellschaft für Technische Zusammenarbeit
(GTZ) and the World Bank, the Ghana government has undertaken a number of initiatives to formalise and regulate small-scale mining operations. Unfortunately, small-scale mining activities are characterised by lack of capital and minimum use of appropriate technology in the mining and treatment of the minerals into finished products. In addition, the industry is associated with land degradation and water pollution. This paper explores possible strategies that aim to make small-scale gold mining in Ghana more sustainable (i.e. more efficient, less destructive to the environment and more meaningful to the operators and the country as a whole). The roles of stakeholders in the small-scale mining industry in Ghana are also identified. It concludes that, for sustainable small-scale mining, a pragmatic synergistic approach must be adopted by all stakeholders in the organisation, regularisation, training and support of small-scale mining operations in Ghana. Mineable lands need to be delineated, illegal operators should be organised and brought under a responsible umbrella, small-scale mining operators should be supported with funds, technology and education, and alternative livelihood programmes must be pursued in mining communities.
Approaches to sustainable minerals development in Zambia
Authors: Nyambe Imasiku A. , Kawamya Vincent M.
Published: April 2008

Zambia is a land-locked country occupying an area of 752 614 km
2
, with the geology dominated by Archaean to Neoproterozoic age rocks that contain significant mineral resources. Economically, the most important of these are the Neoproterozoic Katangan rocks, which yield the copper and cobalt ores exploited in the Zambian Copperbelt. Copper and Cobalt exports account for over 80% of Zambia’s foreign exchange earnings. Coal-bearing rocks of Karoo age (Permo-Carboniferous to Early Jurassic age) occur in rift valley basins such as the mid-Zambezi Valley in the south of the country. Issues such as a lack of capital investment led to privatization of the Zambian large-scale mining industry. Smaller scale gemstone mining is becoming increasingly important. For example, in 1998, the Ministry of Mines and Minerals Development granted over 200 gemstone-mining licences, 30 small-scale mining licences and prospecting permits, and over 70 artisanal mining rights for various minerals. A policy Framework Paper (1999–2001) published by the Zambian Government encourages the formalization of small-scale mining activities through the provision of licences for small-scale mining and gemstone trading, and the establishment of four regional mining bureaus for licensing and other services to the mining community. Furthermore, the Government has embarked on a Mining Sector Diver-sification Project with the support of the European Union, with the objectives of increasing export earnings through economic diversification, generating employment opportunities and contributing to poverty alleviation. In addition, the new policies and legal framework encourage private ownership of medium- and large-scale mining operations, and development of new mines. Currently, all former Government-owned mines that were under Zambia Consolidated Copper Mines Limited have been privatized. These activities are slowly generating much needed new investment to the mineral industry in Zambia. For many years, copper mining has supported the social and economic development of Zambia, accounting for around 90% of all Zambia’s foreign exchange earnings in 1991. Copper reserves are steadily declining, with total reserves remaining estimated at just over 2 billion tonnes at an average grade of 2.51% total copper. There are no recent economic mineral deposits discoveries to replace depleting copper reserves. Lead and zinc mining at Kabwe finished in 1994 due to reserve depletion. The Maamba Coal Mine in the Zambezi Valley is in need of re-equipment and modernization. Gemstone mining and marketing needs a complete overhaul. This paper reviews the major issues that have contributed to decline in sustainable development of the mineral industry in Zambia and highlights initiatives, both private and public, currently undertaken to revitalize the sector.
The emperor’s new clothes: sustainable mining?
Authors: Whitmore Andy
Published: April 2008

Over the last few years, the idea of ‘sustainable mining’ has, thanks to industry sponsorship, been working its way into the agenda of many international processes. There is now a push in many countries to invite in multinational mining companies with the idea that there is a ‘new, sustainable mining’ that is different from the old, bad practices of the past. Yet what has actually changed in the industry to match this shift in rhetoric? From the perspective of mine-affected communities, nothing seems to have changed. Their land is still being taken from them without giving their free, prior and informed consent, and they are suffering the same ill effects on their ways of life, health and environment. This paper will illustrate, using case studies from the Philippines and West Papua, how under this rhetoric, the mining industry ‘emperior’ has the same old naked ambitions. This paper intends to look at how ‘sustainable mining’ is perceived from the viewpoint of mines-affected communities and their supporters. Ideally a representative of such a community should be writing this, but as this was not possible, I am writing this as a member of the editorial board of Mines and Communities (MAC). (MAC is a network of organizations across the world seeking to empower mining-affected communities in their struggles against damaging proposals and projects. More information on Mines and Communities, including the members of its editorial board, can be viewed at http://www.minesandcommunities.org.) Many of the communities MAC works with are made up of indigenous (or first, aboriginal) peoples, who have been unfairly disadvantaged by mineral development on or near their land. The paper will therefore concentrate to some extent on the issues of indigenous communities.
Rifting through a heterogeneous crust: insights from analogue models and application to the Gulf of Corinth
Authors: Mattioni L. , Le Pourhiet L. , Moretti I.
Published: April 2008

We used analogue models to study the fault evolution produced by extension through a heterogeneous crust. In the experiments, the heterogeneous crust consisted of a gently dipping silicone layer surrounded by brittle material. The viscous silicone level simulates a weak, upper crustal nappe stack that formed during a previous phase of shortening. X-ray scanner facilities allowed us to acquire 3D images of the experimental models at regular time invervals and hence to study the fault pattern development and the location of the main depocenters during rifting. The experimental results show that the inherited weak nappe stack acts as a décollement and localizes deformation. In the early stages of extension a system of conjugate high-angle normal faults initiates close to the upper tip of the gently dipping silicone layer near the free surface and propagates upwards, resulting in an initial symmetrical graben configuration. Further extension results in (1) a progressive asymmetry of the rifted zone, due to migration of its right margin down the nappe, (2) a shift of the main depocentre downward along the décollement, and (3) the simultaneous activity of several normal faults within the rifted zone. When the pre-existing silicone layer is oblique to the extension, the normal faults develop in an en echelon array, with a strike intermediate between the azimuth of the gently dipping silicone layer and the extension direction. The experiments also show how rheological differences between areas with potential intracrustal weak layers and adjacent domains without décollement level can lead to significant differences in fault pattern, dimension and orientation of the rifted zone. Complete asymmetry of a rift and switches in fault dip direction between adjacent domains can be explained by the presence of pre-existing upper crustal heterogeneities.
Potential Eocene and Oligocene stratigraphic traps of the Rockall Plateau, NE Atlantic Margin
Authors: McInroy D. B. , Hitchen K. , Stoker M. S.
Published: April 2008

Following thermal uplift during the late Paleocene to early Eocene, the denudation of the subaerial hinterland provided a massive sediment supply that led to the development of a number of large, prograding sedimentary wedge systems flanking the Hatton and Rockall basins. Regional seismic data mapping and borehole data indicate that the wedges are Eocene in age and have a high percentage of coarse clastic material typical of high-energy, fluvial or near-shore marine environments. The prograding wedges have been mapped and can be viewed as large, clastic fairways within which trapping at a number of scales exists. Seismic interpretation suggests that the wedges are present at various stratigraphic levels within the Eocene and are locally separated by unconformities. However, all pre-date the margin-wide late Eocene unconformity (C30), which resulted in subsidence and deepening of the Rockall and Hatton basins. A marine transgression inundated most former land areas, and a marked change occurred in basinal facies; a change from fluvial/near-shore clastic sedimentation to deep-water mud and ooze deposition influenced by bottom-currents. These conditions persisted throughout most of the Oligocene and Neogene and hence provided a seal for potential hydrocarbon-bearing sand-prone Eocene reservoirs internal to the wedge-systems. Additional sealing potential may be provided by shale layers internal to the wedges. Buried Eocene pinchout lobes, submarine fans at the base of basalt scarp faces and Oligocene slump deposits also provide potential trapping mechanisms. High, and probably unacceptable, risks include biodegradation and poor seal development due to the typically shallow depth of burial of the wedges. However, the majority of the wedges should be treated as analogues, with some of the deeper examples providing some scope for consideration as exploration targets. The scale of the prograding wedge play fairway is massive, with volumes measured in tens of cubic kilometres.
Cool-water carbonate ramps: a review
Authors: Pedley Martyn , Carannante Gabriele
Published: April 2008

This review of marine, cool-water carbonate ramps considers both their defining features and the key publications relating to them. Cool-water carbonate environments are dominated by open, skeletal debris-covered sea bottoms which support biological assemblages devoid of hermatypic coral reefs, calcified green algae and non-skeletal grains. The growing body of modern literature deals mainly with Neogene to Recent examples, particularly from the Australian, New Zealand and Mediterranean regions. Nevertheless, many ancient examples have been recognized and, without doubt, many more — currently described as ‘tropical carbonates’ — will also be found to be cool-water examples.
Present-day temperate carbonate sedimentation on the Balearic Platform, western Mediterranean: compositional and textural variation along a low-energy isolated ramp
Authors: Fornós Joan J. , Ahr Wayne M.
Published: April 2008

The pre-1980s literature on modern carbonates was biased toward tropical examples because non-tropical carbonates had not been studied extensively. Though non-tropical carbonates have received considerable attention in the past decade, the variety of low-energy, temperate ramp examples in the literature is limited. In contrast, examples of modern and ancient low-energy, tropical ramps are well represented. They are characterized by a gradual change from calcarenites updip to calcilutites downdip, by a photozoan biota, abundant non-skeletal aragonitic grains, such as ooids and peloids, and by widespread and rapid marine cementation. The Balearic Platform in the western Mediterranean is an isolated, low-energy, temperate ramp. This paper describes the Balearic ramp bathymetry, environmental regimes and depositional facies, which include (from the shoreline seaward): coastal lagoons, beach—dune complexes, inner-ramp seagrass meadows with mixed terrigenous—foraminiferal—molluscan muddy calcarenites, middle-ramp bryozoan—rhodalgal facies and outer ramp clastic—carbonate muds. Biotic and textural characteristics vary with depth, with hydrological conditions and with environmental factors, such as temperature, salinity, light and nutrients. Seagrasses extend across the inner and part of the middle ramp, where the grasses offer shelter to a variety organisms, including epibionts, molluscs, bryozoans, echinoderms and red algae. Most of the beach and dune sediments consist of bioclasts derived from the communities that thrive in the seagrass meadows, but the greatest volume of skeletal carbonates is produced as bryozoan, rhodalgal and molluscan gravels that occur as patchy blankets, primarily on the middle ramp. The Balearic Platform is characterized by an oligotrophic, clear water, microtidal environment. The dominant biota of the Balearic ramp — bryozoans, red algae, echinoderms and molluscs — is common in other non-tropical modern environments as well as in ancient temperate settings. This fact, combined with the absence of aragonitic non-skeletal grains, abundant marine cements and photozoans other than red algae, establishes the modern Balearic ramp as a model for comparison with low-energy, non-tropical ramps in the global rock record.
Variety of coralline algal deposits (rhodalgal facies) from the Bays of Naples and Pozzuoli (northern Tyrrhenian Sea, Italy)
Authors: Toscano Francesco , Vigliotti Marco , Simone Lucia
Published: April 2008

The occurrence and variability of the coralline algal (rhodalgal) facies both in active factories and in palimpsest and/or winnowed deposits in the Bay of Naples and the Bay of Pozzuoli is reported. The present-day coralline algal deposits resulted from the complex volcano-tectonic events and biological changes which occurred in the Phlegrean Fields, in particular after the sea-level lowstand at the last glacial maximum regression and the succeeding Holocene transgression.
Biocalcarenite and mixed cool-water prograding bodies of the Mediterranean Pliocene and Pleistocene: architecture, depositional setting and forcing factors
Authors: Massari F. , Chiocci F.
Published: April 2008

Plio-Quaternary basinward-prograding heterozoan carbonate wedges with seawarddipping, steep clinoforms and significant along-strike extension, are common both on land and along the submerged margins of the Mediterranean area. They developed as distally steepened ramps on storm-dominated, relatively steep-gradient margins, commonly controlled by tectonics. Dispersal of the skeletal hash was mainly due to storm-driven downwelling and geostrophic currents, changing into gravity flows down the clinoformed ramp margin. Due to active winnowing and bypass in the shallow-water settings, biocalcarenite ramps were entirely detached from the shoreline. Sequence-stratigraphic architecture of cropping out prograding bodies indicates the presence of internal unconformity surfaces bounding shingled units with sigmoidal to oblique clinoforms. Similar wedges identified by seismic survey on the margins of the Tyrrhenian Sea generally show a back-stepping pattern, with the deeper-located wedges related to the last lowstand and the subsequent wedges reflecting episodic stillstands during sea-level rise. A critical role in determining the efficiency of the carbonate factory is thought to have been played by the increase in the strength of atmospheric and marine circulation which accompanied the long-term climatic change affecting the Mediterranean area since 3.1 Ma, especially during cooler to colder stages.
The response of cool-water carbonates to eustatic change in microtidal, Mediterranean Quaternary settings of Sicily
Authors: Pedley Martyn , Grasso Mario
Published: April 2008

Information concerning the glacio-eustatic controls on Quaternary cool-water carbonates is dominated by data contained within the Holocene to Recent marine shelf record. However, this information represents only part of a full eustatic cycle. Much of the data comes from Southern Ocean-based biofacies studies associated with seafloor sediments. Geophysical studies provide further information on earlier Quaternary seafloor deposits and yield valuable data on sediment geometries; however, these works yield little direct information that can be applied to carbonates at outcrop scale. In contrast, Quaternary cool-water carbonates in the Mediterranean region offer outcrops with continuous exposure along which facies changes are readily accessible for study. In southern Italy and Sicily in particular, post-depositional uplift permits outcrop-based studies of large tracts of Quaternary microtidal cool-water carbonates, containing complete interglacial eustatic cycles. The study examines the carbonates associated with the Emilian sub-stage of the early Quaternary Calabrian Stage.
Rudist lithosomes related to current pathways in Upper Cretaceous temperate-type, inner shelves: a case study from the Cilento area, southern Italy
Authors: Ruberti Daniela , Toscano Francesco , Carannante Gabriele , Simone Lucia
Published: April 2008

Shallow-water foramol limestones have been studied from a locality in the southern Apennines in which outcrop conditions show an excellent overview of the lateral and vertical evolution of rudist bodies and allow their geometry and the dynamic aspects to be reconstructed. The lithofacies suggest open depositional settings characterized by peloidal silty-muddy sediments. Rudists inhabited well-defined sectors of these shelves, giving rise to wide biostromal bodies, and supplied most of the skeletal debris via bioerosion and minor physical breakdown. In particular, the characteristics of rudist lithosomes document the existence of a complex network of channel-like depressions. In such a depositional context, the evolution of rudist lithosomes was controlled by the environmental hydrodynamic conditions. The resulting composite rudist assemblages are characterized by often-toppled individuals, suggesting continuous sediment removal between the organisms. The good preservation of the shells and the common articulation of the valves, however, point to an absence of sustained transport but rather a slight sediment destabilization. The gross lenticular geometry of the shell beds could be related to the above-mentioned patterns of weak, perhaps channelized, pathways. In such a depositional context, rudist colonization on channel margins assumes particular importance as it documents the rudist ability to exploit a wide array of environments, comparable to that of oysters in Recent seas, and reflecting the probable opportunistic nature of rudists.
Cool-water shell bed taphofacies from Miocene-Pliocene shelf sequences in New Zealand: utility of taphofacies in sequence stratigraphic analysis
Authors: Hendy Austin J. W. , Kamp Peter J. J. , Vonk Adam J.
Published: April 2008

An investigation of the taphonomy, palaeoecology and stratigraphy of cool-water skeletal concentrations (shell beds) of the Matemateaonga Formation (Late Miocene-Early Pliocene) of Wanganui Basin, New Zealand, has provided the basis for the classification of taphofacies presented here. Two taphofacies described from transgressive systems tracts include the amalgamated shell bed and sediment starved shell bed taphofacies, representing skeletal concentration dominated by wave and current agitation, and sediment starvation, respectively. A further five taphofacies described from highstand and regressive systems tracts exhibit a gradient of sedimentological, taphonomic and palaeoecological properties that result from variation in storm event and fair-weather wave processes across the palaeoshelf bathymetric gradient. A principal components analysis of semi-quantitative data (53 observations) from sequences in Manutahi-1 well core demonstrates that taphonomic properties may be limited to particular systems tracts in some cases, but can also be repeated in different system tracts where the depositional environments are similar. Taphofacies, which are contained within siliciclastic-dominated portions of sequences (highstand and regressive systems tracts) possess little direct relevance to sequence stratigraphic analyses, but do provide valuable information on environmental conditions, in particular, depth relative to storm and fair-weather wave base, and proximity to shoreline.
History of the meteorite collection of the Natural History Museum of Vienna
Authors: Brandstätter F.
Published: April 2008

The meteorite collection of the Natural History Museum of Vienna has the longest history of all comparable collections in the world. In the second half of the 18th century, soon after the foundation of the Imperial Natural History Cabinet in 1748, the Viennese curators began to collect meteorites. Owing to the efforts and scientific interest in meteorites of Carl von Schreibers (1775–1852) and his successors the Vienna collection became the largest and most extensive in the course of the 19th century. Simultaneously, the collection and its curators became one of the centres of the newly established science of meteoritics. The outbreak of the First World War and the fall of the Austro-Hungarian Monarchy brought all these research activities and the growth of the collections at the Viennese museum to an abrupt end. Modest activities between the world wars were interrupted by the onset of the Second World War, again leading to a complete halt. It was not before the late 1960s that the situation improved and a budget for purchases permitted the acquisition of select contemporary meteorite falls and finds. From then on, the meteorites in the collection had again been used intensively for research purposes. Up until the end of the year 2003, the meteorite collection had increased to a total of 2336 localities.
Characterization of Maltese pottery of the Late Neolithic, Bronze Age and Punic Period by neutron activation analysis
Authors: Mommsen H. , Bonanno A. , Chetcuti Bonavita K. , Kakoulli I. , Musumeci M. , Sagona C. , Schwedt A. , Vella N. C. , Zacharias N.
Published: April 2008

A set of 41 samples from Tas-Silg, Malta, has been analysed by neutron activation. It contained nine ware groups formed by visual examination covering the Late Neolithic, Bronze Age and Punic Periods (
c.
3000-218
bc
). Despite this diversity and long time range, seven of these ware groups, including the ‘Thermi Ware’, all have a similar chemical composition and, therefore, have been made from the same clay. This points most probably to a local origin. One group from the Punic Period, containing only Bricky Red cooking ware, is chemically separate and represents a second distinct pattern probably assignable to a local production. Five amphora sherds also from the Punic Period, and consisting of a micaceous fabric, all have different chemical characteristics and are probably imports from overseas production sites of unknown location.
Cobalt blue painted pottery from 18th Dynasty Egypt
Authors: Shortland A. J. , Hope C. A. , Tite M. S.
Published: April 2008

Cobalt blue painted pottery was produced in New Kingdom Egypt, with the heyday for its production being from about 1400
bc
to 1200
bc
. Previous scientific examination has established that the cobalt blue pigment was a CoAl-spinel, which it was suggested was produced from cobaltiferous alums from the Western Desert of Egypt. In the present paper, quantitative analyses of a range of cobalt blue painted pottery have confirmed the Western Desert as the source of the cobalt blue pigment but suggested that the cobaltiferous alums used for the pottery differed in composition from those used in the production of contemporary cobalt blue glass. The pottery bodies were produced using either non-calcareous Nile silt or calcareous clay. Before being painted, the Nile silt bodies were first coated with pale firing calcareous clay slip to which gypsum had probably been added.
Golden mica cooking pottery from Gökeyüp (Manisa), Turkey
Authors: Çolak Mümtaz , Maggetti Marino , Galetti Giulio
Published: April 2008

Gökeyüp cooking pottery is a particular type of pottery produced according to ancient craft tradition in western Turkey. It is made by mixing 75 wt% of local red and green smectitic clays with 25 wt% of local gneissic temper. Both temper and tempered objects are rich in MgO, as can be seen from XRF analyses. The vessels are coated with a sheet-silicate enriched layer, corresponding to the <2 mm sieved fraction of the crushed gneissic temper. The pottery is fired for 45 min using the bonfire technique. Apart from the dehydroxylation of the smectites, no clear mineralogical difference can be observed between the unfired and fired products. The reduction factor FeO/FeO
tot
reveals no significant oxidizing or reducing firing conditions. As evidenced by SEM-EDS analyses, there is no chemical difference between the unfired and externally fired micas of the coating. The golden colouring is therefore due to the oxidation of the biotites during firing.
Glass production in Late Antiquity and the Early Islamic period: a geochemical perspective
Authors: Freestone Ian C.
Published: April 2008

First millennium
ad
glass production was divided between a relatively small number of workshops that made raw glass and a large number of secondary workshops that fabricated vessels. Glass compositions reflect the primary glassmaking source. For most of the period, Egyptian mineral soda was fused with lime-bearing siliceous sand to produce soda-lime-silica glass. The location of the Belus glassmaking sand, which is known from the classical literature, is located on that part of the Levantine coast where iron contents are lowest.
87
Sr/
86
Sr of primary glass from workshops in the Levantine region is close to that of modern seawater, and confirms the use of beach sand, which contained shell. Heavy mineral assemblages of Levantine beach sands are dominated by hornblende, hence the primary glasses are characterized by very similar trace element signatures. Glasses believed on archaeological grounds to have been made in other regions, for example in inland Egypt, may have higher
87
Sr/
86
Sr, reflecting terrigenous sources of lime, and have different trace element signatures. Compositional data for glasses from as far away as Britain suggest origins of the glass material in the Eastern Mediterranean. Recycling of old glass may be recognized by the presence of elevated transition metals. The use of plant ash as a flux became dominant practice in the ninth century and preliminary data for plant ash glasses from the early Islamic world indicate that primary production centres may be separated using strontium and oxygen isotopes as well as by major and trace elements.
Biostratigraphy of the Mosasauridae (Reptilia) from the Cretaceous of Antarctica
Authors: Martin James E.
Published: April 2008

Field expeditions to Seymour, James Ross and Vega islands, Antarctic Peninsula, have resulted in significant specimens of mosasurs (marine lizards). Enough taxonomic diversity is now known to allow preliminary biostratigraphic assessment. These specimens were collected from the Late Campanian levels of the Santa Marta Formation and the Late Campanian-Late Maastrichtian López de Bertodano Formation. All specimens are from near-shore marine deposits, and an overall shallowing appears in younger successions. Most mosasaur individuals are represented by single specimens, but, in some cases, jaws and cranial material are preserved. Based on these specimens, tylosaurines appear in the Santa Marta Formation and extend into the López de Bertodano Formation, and Plioplate-carpines and mosasaurines occur in the upper López de Bertodano Formation. Therefore, the extent of mosasaur ranges in Antarctica is similar to that elsewhere in the world where the bulk of mosasaur differentiation occurred in the Campanian and Maastrichtian. Not enough specimens are available from the Campanian sedimentary rocks to determine whether the faunal turnover during the Campanian-Maastrichtian in North America exists in Antarctica. Some differences in taxa occur between Antarctica and elsewhere, but these are at generic levels, not subfamilial. Even so, most genera are similar, but the tylosaurines may be endemic, and, if the
Moanasaurus
reference is substantiated, this genus is also known only in New Zealand and Antarctica. Therefore, the ranges and occurrences of taxa suggest a mix of endemic and cosmopolitan genera. Additional field investigations are required to refine biostratigraphic ranges, and the ranges of many taxa such as those of
Mosasaurus
and
Plioplatecarpus
will be extended into older deposits.
Eustatically controlled sedimentation recorded by Eocene strata of the James Ross Basin, Antarctica
Authors: Marenssi Sergio A.
Published: April 2008

The Eocene La Meseta Formation is an unconformity-bounded unit that records the geological evolution of the James Ross Basin, NE Antarctic Peninsula, during a period of decreasing tectonism and a lull in volcanic activity. This unit represents a composite incised valley, filled with deltaic, estuarine and shallow-marine deposits showing a landwards facies shift that indicates deposition during an overall sea-level rise. The six unconformity-based internal units (Valle de las Focas, Acantilados, Campamento,
Cucullaea
I,
Cucullaea
II and Submeseta allomembers) are interpreted to represent minor-scale regressive-transgressive events. Geological, palaeontological and new strontium isotopic ages allow the correlation of base-level changes with second- and third-order eustatic sea-level fluctuations. The base of the La Meseta Formation is correlated with a global 56 Ma lowstand in sea level followed by a main episode of flooding between 54.3 and 52.4 Ma. The base of the
Cucullaea
I Allomember is correlated with the well-known late Ypresian (49 Ma) lowstand, and the base of the Submeseta Allomember with the 36 Ma lowstand. Correlation of Eocene sea-level fluctuations in the northern Antarctic Peninsula with the global sea-level curve strengthens the concept of global syncroneity of the eustatic sea-level curve.
First gondwanatherian mammal from Antarctica
Authors: Goin Francisco J. , Reguero Marcelo A. , Pascual Rosendo , von Koenigswald Wighart , Woodburne Michael O. , Case Judd A. , Marenssi Sergio A. , Vieytes Carolina , Vizcaíno Sergio F.
Published: April 2008

Gondwanatherians are an enigmatic group of extinct non-therian mammals apparently restricted to some of the western Gondwanan continents (Late Cretaceous-early Palaeocene of South America, and Late Cretaceous of Madagascar and India). They developed rodent-like incisors and the earliest known hypsodont cheek-teeth among mammals. Recently, a small rodent-like dentary fragment was recovered from middle Eocene beds on the Antarctic Peninsula, preserving part of the incisor; both the incisor enamel structure and the mandibular morphology suggest close affinities with
Sudamerica ameghinoi
from the early Palaeocene of Patagonia, up to now the youngest known Gondwanatheria. Thus, the new specimen becomes the youngest occurrence of a gondwanathere, adding significant direct and indirect evidence on: (1) the already documented cosmopolitanism of gondwanatheres among Gondwanan mammals; and (2) the crucial biogeographical role of Antarctica during the Cretaceous-Tertiary mammalian transition.
Tectonic development of the Eastern Mediterranean region: an introduction
Authors: Robertson Alastair H. F. , Mountrakis Demosthenis
Published: April 2008

The Eastern Mediterranean is one of the key regions for the understanding of fundamental tectonic processes, including continental rifting, passive margins, ophiolites, subduction, accretion, collision and post-collisional exhumation. It is also ideal for understanding the interaction of tectonic, sedimentary, igneous and metamorphic processes through time that eventually lead to the development of an orogenic belt. Below, we will outline some milestones in the development of tectonic-related research in the Eastern Mediterranean region. We will mention how studies of the Eastern Mediterranean contribute to our understanding of fundamental tectonic processes and indicate how papers in this volume contribute to this aim. Current and emerging research themes will be highlighted. We will also outline the main alternative tectonic reconstructions of the region (see Fig. 1), and mention which of these the different contributors favour. Tethyan nomenclature remains controversial and we will suggest an appropriate informal terminology for the various oceanic basins that existed. An entrée to some of the key literature sources is also provided. Citations here are mainly to edited volumes, which provide access to this large subject area.

Many of the papers in this book integrate and synthesize large amounts of geological information for extended periods of geological time. The papers are ordered in a general time sequence with a view to linking those that consider comparable tectonic setting and processes. The locations of the areas are shown in Figures 2 and 3. Figure 2 also shows the main sutures, and Figure 3 illustrates the main neotectonic elements of the region.
Tethyan ophiolite emplacement, Africa to Europe motions, and Atlantic spreading
Authors: Smith A. G.
Published: April 2008

Final emplacement of the mid-Jurassic and mid-Cretaceous supra-subduction zone (SSZ) ophiolites onto adjacent continental areas in the Mediterranean region is synchronous with reductions in the rate of motion between Africa and stable Europe. The Apennine-Ligurian-Alpine ophiolites lack SSZ chemistry, are mid-ocean ridge basalt (MORB)-like, range in age fromc.169 to 148 Ma, and were emplaced in late Cretaceous and Cenozoic time. The Hellenic-Dinaric SSZ ophiolites include some MORB, ranging from 173 to 168 Ma, and were emplaced, eroded, and covered by younger sediments byc.140 Ma. The creation of the Apennine-Ligurian-Alpine and Hellenic-Dinaric suites is attributed to the motion of Adria, which formed a promontory on Africa, or essentially moved with it, as the central Atlantic opened. Extension to the west of Adria gave rise to the Ligurian Sea, generating MORB crust; to the east, a pre-existing Triassic ocean was subducted, with rollback creating Jurassic SSZ ophiolites that were emplaced onto adjacent continental margins in the later stages of convergence. The two episodes of slower motions between Africa and Europe are attributed to two episodes of attempted subduction of a passive continental margin. This speculation suggests that emplacement of some SSZ ophiolites may exert a significant control on oceanic spreading patterns.
Late Proterozoic and Silurian basement units within the Serbo-Macedonian Massif, northern Greece: the significance of terrane accretion in the Hellenides
Authors: Himmerkus F. , Reischmann T. , Kostopoulos D.
Published: April 2008

The Serbo-Macedonian Massif (SMM) is a large, elongate basement complex in the Internal Hellenides, which stretches from Serbia to the Chalkidiki Peninsula in northern Greece. As a result of similarities in lithology and structural grain, the SMM has long been considered part of the adjacent Rhodope Massif. Recent work, however, based on precise geochronological and geochemical data, has revealed that the SMM is not a homogeneous crustal entity but made up of several crustal units, only one of which is related to the Rhodope Massif. One of these units, the Pirgadikia Unit, occurs as a tectonic sliver in a mélange zone bordering the western margin of the SMM that separates it from the adjacent Vardar Zone. The Pirgadikia Unit consists of leucocratic mylonitic para- and orthogneisses. According to trace-element and Sr-isotope data, the orthogneisses originated in a magmatic arc setting. Dating of this unit by the Pb-Pb single-zircon evaporation method yielded Pan-African ages of 555.8±2.6 Ma on a paragneiss collected near the village of Taxiarchis, and two ages of 570.0±7.0 Ma and 587.6±3.4 Ma on orthogneisses from the quayside at Pirgadikia village. The rocks enveloping this Late Precambrian basement complex are gneisses of the Vertiskos Unit. This unit, which is regarded as a distinct terrane, occupies the northwestern part of the Greek SMM and consists of Silurian orthogneisses with a magmatic arc signature and subordinate metasediments. Orthogneisses of the Vertiskos Unit adjacent to the mylonites of the Pirgadikia Unit gave Pb-Pb ages of between 428.2±1.2 Ma and 433.0±2.1 Ma. One of these samples was additionally dated by the conventional U-Pb method. This sample has three concordant zircon grains confirming a Silurian intrusion age and two inherited cores pointing to an older basement into which precursor rocks to the Silurian gneisses were intruded. The upper intercept of a Concordia plot yielded an age of
c
. 2.5 Ga, which is a common age in the cratons of Gondwana. The Pan-African age of the Pirgadikia Unit and the inherited ages of the Vertiskos Unit support the notion that these units are terranes derived from Gondwana. They were finally accreted to the Hellenic orogen during the closure of one of the branches of the Tethys Ocean. The presence of exotic terranes in the Internal Hellenides contradicts the hypothesis that this part of the Hellenides formed a stable hinterland during the Alpine phase and thus the Hellenides can be considered an accretionary orogen.
Sedimentary evidence from the south Mediterranean region (Sicily, Crete, Peloponnese, Evia) used to test alternative models for the regional tectonic setting of Tethys during Late Palaeozoic-Early Mesozoic time
Authors: Robertson A. H. F.
Published: April 2008

The south Mediterranean region, including western Sicily, Crete and mainland Greece (southern Peloponnese and Evia), is critical to an interpretation of the Late Palaeozoic-Early Mesozoic tectonic evolution of Tethys. Several contrasting tectonic models compete to explain the regional evolution. In a divergence-related hypothesis (Model 1) the south Aegean region experienced pulsed rifting along the northern margin of Gondwana that culminated in break-up to form the Pindos ocean in the region of Greece. In an alternative convergence-related hypothesis (Model 2) the south Aegean experienced Late Palaeozoic Early Mesozoic northward subduction, accretion and arc magmatism, culminating in ‘Cimmerian’ suturing of a Palaeotethyan ocean in latest Triassic time. In a third model, southward subduction of a Palaeotethyan ocean took place beneath the North Gondwana margin during Late Palaeozoic-Triassic time, giving rise to back-arc magmatism in an extensional setting. In addition, a more complex setting involving two opposing subduction zones (Andean-type and intra-oceanic) has also been suggested (Model 4), mainly based on lava geochemistry. To test these tectonic alternatives, mainly sedimentary studies were carried out in western Sicily, western and eastern Crete, the Peloponnese and Evia (eastern central Greece). Western Sicily was studied as a proxy for the unexposed deep Mediterranean south of Crete. Most of the available evidence supports the divergence-related (pulsed rift) hypothesis (Model 1). There is no clear evidence of sea-floor spreading (e.g. ophiolites) to the south of what became the Pindos ocean, or of plate convergence (e.g. magmatic arcs, subduction complexes), or collisional deformation in the south Aegean region that could be related to subduction or collision during the Mid-Carboniferous to Triassic, as in Model 2. Model 3 is not supported by evidence from the wider region (northern Greece, Turkey). Model 4 is not supported by evidence independent of igneous geochemistry. In the proposed interpretation, the northern margin of Gondwana initially rifted during Mid-Carboniferous to Early Permian time to form a wide deep-water basin. This was followed by further rifting, associated with volcanism during the Early Triassic; final continental break-up and spreading to form the Pindos ocean to the north during Late Triassic to Early Jurassic time then followed. Mid-Triassic uplift of part of the rift basin is explained as a flexural response to rifting as a precursor to opening of the Pindos ocean. Passive margin subsidence during the Early Mesozoic relates to opening of the Pindos ocean to the north. A subduction geochemical signature within some Triassic volcanic rocks, in this interpretation, is explained by melting of heterogeneous sub-crustal mantle, following an earlier, possibly Hercynian, subduction event.
Tectonic and sedimentary evolution of the Cenozoic Hatay Graben, Southern Turkey: a two-phase model for graben formation
Authors: Boulton Sarah J. , Robertson Alastair H. F. , Ünlügenç Ulvi C.
Published: April 2008

New structural and sedimentary studies form the basis of a new interpretation for the Neogene Hatay Graben. Fault analysis reveals three contemporaneous trends of fault orientation (000°–180°, 045°–225° and 150°–350°) suggesting that the graben is transtensional in nature. Sedimentary studies show that, following shallow-marine deposition from the Late Cretaceous to the Eocene, a hiatus ensued until Early Miocene fluvial sedimentation. After a Mid-Miocene marine transgression, water depths increased until the Messinian salinity crisis, followed by a regression from the Pliocene to the present day. The basin initially developed as the distal margin of a foreland basin of the Tauride allochthon to the north, developing a classic sedimentary sequence during Mid-Late Miocene. Stresses caused by loading of the crust created a flexural forebulge to the south that supplied sediment mainly northwards. During the Plio-Quaternary, transtensional graben development took place, primarily influenced by the westward tectonic escape of Anatolia along the East Anatolia Fault Zone and left-lateral offset along the northward extension of the Dead Sea Transform Fault. This area is, thus, an excellent example of a foreland basin reactivated in a strike-slip setting. Our new two-phase model: foreland basin, then transtensional basin for the Hatay Graben, is in contrast to previous models, in which it was generally assumed that the Plio-Quaternary Hatay Graben represents a direct extension of the Dead Sea Fault Zone or the East Anatolian Fault Zone.
Multifractal variability in self-potential signals measured in seismic areas
Authors: Telesca Luciano , Lapenna Vincenzo , Macchiato Maria
Published: April 2008

Multifractal variability in the time dynamics of geoelectrical data, recorded in a seismic area of southern Italy, was studied by means of Multifractal Detrended Fluctuation Analysis (MF-DFA), which allows the detection of multifractality in nonstationary signals. Our findings show that the multifractality of the geoelectrical time series recorded in the study area is mainly due to the different long-range correlations for small and large fluctuations. Furthermore, the singularity spectrum has led to a better description of the signal, revealing a clear enhancement of its degree of multifractality (measured by the variation of the standard deviation of the generalized Hurst exponents
h
(
q
) or the Hölder exponents α) in association with the occurrence of the largest earthquake. However, in order to assess significant correlations between large earthquakes and patterns of multifractal parameters, an investigation of data sets covering longer periods and different seismotectonic environments is needed. The study also furnishes details on our approach for investigating the complex dynamics of earthquake-related geoelectrical signals.
A general landslide distribution applied to a small inventory in Todi, Italy
Authors: Turcotte Donald L. , Malamud Bruce D. , Guzzetti Fausto , Reichenbach Paola
Published: April 2008

Large numbers of landslides can be associated with a trigger, for example, an earthquake or a large storm. We have previously hypothesized that the frequency—area statistics of landslides triggered in an event are well approximated by a three-parameter inverse-gamma distribution, irrespective of the trigger type. The use of this general distribution was established using three substantially complete and well-documented landslide event inventories: 11,000 landslides triggered by the Northridge California Earthquake, 4000 landslides triggered by rapidly melting snow cover in the Umbria region of Italy, and 9000 landslides triggered by heavy rainfall associated with Hurricane Mitch in Guatemala. In this paper, we examine further this general landslide distribution by using an inventory of 165 landslides triggered by heavy rainfall in the region of Todi, Central Italy. Our previous studies have shown the applicability of our general landslide distribution to events with 4000–11,000 landslides. This smaller inventory provides a critical step in examining the applicability of the general landslide distribution. We find very good agreement of the Todi event with our general distribution. This also provides support for our further hypothesis that the mean area of landslides triggered by an event is approximately independent of the event size.