bluuebunny/crossref_metadata_2025_split huggingface dataset:
Inhibition of Hepadnavirus Reverse Transcriptase-ε RNA Interaction by Porphyrin Compounds
Authors: Lin Li , Hu Jianming 
Published: December 2007

ABSTRACT
The hepatitis B virus (HBV) reverse transcriptase (RT) plays a multitude of fundamental roles in the viral life cycle and is the key target in the development of anti-HBV chemotherapy. We report here that the endogenous small molecule iron protoporphyrin IX (hemin) and several related porphyrin compounds potently blocked a critical RT interaction with the viral RNA packaging signal/origin of replication, called ε. As RT-ε interaction is essential for the initiation of viral reverse transcription, which is primed by RT itself (protein priming), the porphyrin compounds dramatically suppressed the protein-priming reaction. Further studies demonstrated that these compounds could target the unique N-terminal domain of the RT protein, the so-called terminal protein. Hemin and related porphyrin compounds thus represent a novel class of agents that can block HBV RT functions through a mechanism and target that are completely distinct from those of existing anti-HBV drugs.
The use of microplankton in resolving stratigraphical problems in the Eocene of the Isle of Wight
Authors: EATON GEOFFREY LEONARD 
Published: December 2007

THE FIRST STAGE in this investigation of the microplankton (dinoflagellate cysts and acritarchs) of the Bracklesham Beds of the Isle of Wight has involved the re-examination of the classic Eocene cliff sections at Whitecliff Bay in the east and Alum Bay in the west.

Fisher’s concept of the type section of the Bracklesham Beds at Whitecliff Bay (
Fisher 1862
) formed the basis of the present study, although his interpretation of the lithological divisions has been slightly modified.

At Alum Bay the Bagshot and Bracklesham Beds have been redefined. Several breaks have been noted in the sequence, all but one of which are succeeded by a pebble bed.

Rich microplankton assemblages have been recovered from the Bracklesham Beds of both sections. Mollusca and Foraminifera are essentially restricted to the marine clays and greensands. Microplankton also occur in these sediments and in the ‘laminated beds’ (
Fisher 1862
, p. 67). This difference in distribution is particularly significant at Alum Bay where all but the highest 16 metres (52 feet) of the Bracklesham Beds were previously thought to be devoid of marine fossils.

The stratigraphical ranges of selected microplankton species have been used to define five microplankton zones in the type section of the Bracklesham Beds at Whitecliff Bay. All five zones have been recognized in the redefined Bracklesham Beds at Alum Bay, and the divisions within the Bracklesham Beds of both sections have been correlated for the first time.
As a result of this correlation the following conclusions were reached concerning the section
The Mozambique orogenic belt and its foreland in northeast Tanzania: a photogeologically-based study
Authors: HEPWORTH JOHN VORD 
Published: December 2007

The tectonic relationships within a rather large part (130,000 sq. km) of the Mozambique orogenic belt in N.E. Tanzania were investigated by photogeological interpretation and ground control Within the granitoid foreland (part of the Tanganyika Shield) the Dodoman and Nyanzian Greenstone belts, and charnockitie granulites are recognized. These were intruded and replaced by the chelogenie Katarchaean granite.
Within the orogenic belt pre-Mozambiquian gneisses (termed Parangan) are exposed at the western margin, and in the floor of the orogen. These were tectonically reworked and transformed into L-tectonites and flaggy gneisses in the main Mozambiquian tectonism (termed Kondoan): this took place by strong folding about south-easterly-plunging axes, the folds being characteristically reclined.
It is observed that structures transverse to the regional trend are a feature of other orogenic fronts such as the Grenville and Caledonian. In Tanzania they are succeeded by flexure folds on nne axes (termed Bongan), which locally become the predominant structures, parallel to the regional trend. In the north they are overturned towards the foreland and over-ride it.
The Mozambiquian tectonism deforms the margin of the Shield and may penetrate it for considerable distances, perhaps contributing to the deformation in the Greenstone belts.
The development of vein and rock textures by tensile strain crystallization
Authors: PHILLIPS WILLIAM J. 
Published: December 2007

The characteristics of fibrous veins of gypsum and other minerals are described and it is concluded that the growth of the fibres kept pace with the dilation of the veins because fluid pressures were in excess of lithostatic pressures but less than the combined lithostatic pressures and tensile strengths of the fibres. Crystallization in the regions of greatest tensile strain in the fibres would be promoted by the greater probability of atoms being accommodated in the crystal structure. The free energy associated with the crystal dislocations which are likely to be concentrated in these regions would contribute to the crystallization process and allow it to proceed at very low levels of supersaturation. Crystallization during tensile strain explains the common occurrence of strain effects such as undulose extinction and dislocation planes in fibrous crystals.
It is suggested that polycrystalline aggregates may deform under triaxial stress by pressure solution of the grains on planes approximately perpendicular to the direction of greatest stress and simultaneous crystallization of elongate crystals in the direction of maximum extension from the points of concentrated tensile strain. Tensile strain crystallization may be an important mechanism in the development of penetrative preferred orientations in metamorphic rocks.
Upper Cretaceous and Cenozoic carbonates from the margins of Rockall Trough, N. Atlantic
Authors: DOBSON M. R. , GARRETT P. , HAYNES J. R. , JENKINS D. GRAHAM , MEDANI A. H. 
Published: December 2007

Dredged carbonates from the margins of Rockall Trough mostly represent hard grounds made up of outer shelf benthonic skeletal assemblages and pelagic ooze. Chertification and occasional iron impregnation either as a crust or dominant association, are particular features of these rocks which have frequently suffered a complex history of cementation.
Further micropalaeontological work allows the dating to be refined and the Tertiary carbonates are shown to contain upper Eocene microfaunas that have been transported and rolled prior to final lithification, probably during the post-Eocene erosion interval widely reported in the Northeast Atlantic, Reflector R4.
Metamorphic rocks in the SW Ox Mountains Inlier, Ireland; their structural compartmentation and place in the Caledonian orogen
Authors: LONG C. B. , MAX M. D. 
Published: December 2007

Three tectono-sedimentary units having Caledonian tectono-thermal histories are recognized within the metamorphic rocks of the SW Ox Mountains Inlier. The different structural levels represented by each of these units were juxtaposed along tectonic contacts late in the individual tectono-thermal histories. The highest structural unit is the virtually unmetamorphosed, probably Southern Highland (Upper) Dalradian, Ardvarney Formation which can be related on a regional scale to the Donegal 'Tay Nappe' structure. The Raheen Barr succession probably ranges from the Islay to Easdale subgroups of the Middle Dalradian and can be correlated with the metamorphic rocks of the Nephin Beg succession in NW Co. Mayo. The Ox Mountains succession represents the deepest structural level seen and consists of basic volcanic rock, graphite schist, marble quartzite, psammite, and semi-pelite. It forms the envelope to the syn- to late kinematic 500 ± 18 Ma Ox Mountains Granodiorite and stratigraphically it can best be compared with the Appin and Argyll groups of the Dalradian of Connemara.
The differing tectono-thermal histories of the different structural levels in this part of the metamorphic Caledonides of western Ireland possibly reflect the diachronous nature of the deformation and metamorphism in the orogen. Interaction during juxtaposition must have involved movement related to more than one direction of tectonic transport.
Diagenetic sequences in low-permeability argillaceous sandstones
Authors: Thomas J. B. 
Published: December 2007

A regular sequence of mineral paragenesis is observed in low-permeability (‘tight’), very fine-grained sandstones of brackish marine to fresh water origin in portions of the Cretaceous of the Rocky Mountains, North America. From pore throat to pore centre in these rocks, the common authigenic sequence is illite (pore throat), kaolinite, silica (pore centre), and siderite (pore centre but after silica). Associated fine- to medium-grained sandstones exhibit a sequence of quartz followed by kaolinite plus traces of calcite from pore throat to centre.
Comparison of Gibbs' free energies of formation calculated by the method of Tardy & Garrels show values decreasing in the same order as paragenesis (illite, kaolinite, silica, siderite) observed in the low permeability very fine-grained sandstones. Diagenetic sequences in the coarser sandstones do not match the order of free energies of formation. This implies that early precipitation in very fine-grained sandstones probably occurs under nearly static conditions, whereas constant fluid throughput in coarser grained rocks leads to a markedly different diagenetic sequence. Thus, two potential sandstone reservoirs, one coarse and one very fine, commonly will have different authigenic mineral suites though their original pore waters were broadly identical.
Possible links between sandstone diagenesis and depth-related geochemical reactions occurring in enclosing mudstones
Authors: Curtis C. D. 
Published: December 2007

Within compacting mudstone sequences several depth zones can be recognised in which distinctive diagenetic reactions take place. Most striking are those involving carbonate precipitation or replacement. The major carbon source is organic matter which is degraded by various microbiological and inorganic reactions to bicarbonate as one product. Other reactions involving silicates and sesquioxides introduce cations to the porewater system and carbonates are precipitated. Their chemical and isotopic composition can be linked with temperature and depth of formation.
Analysis of some of the literature of sandstone diagenesis suggests that carbonate cements in sandstones often originate in mudstones, and that precipitation may take place far from the site of solute generation. Vast volumes of porewater excluded from mudstones during compaction are channelled into and travel great distances within sand units. Early diagenetic reactions drastically modify the permeability of both potential source and reservoir rocks. The component of horizontal flow is greatly increased and this must affect later migration of liquid hydrocarbons.
The Andean geosyncline in Peru, and its distinction from Alpine geosynclines
Authors: Cobbing E. J. 
Published: December 2007

The Andean geosyncline in Peru is divided into faulted strips of crust. This has resulted in the isolation of basins of deposition which have both subsided and deformed independently. Five basins were formed, two of which were filled with sediments and pertain to the miogeosyncline, two with volcanics form the eugoesyncline, and a fifth composed of both volcanics and sediments forms a miogeanticlinal horst between the two.
A volcano-plutonic chain was superimposed upon the fractured continental crust and the eugeosyncline was filled with material derived from the volcanoes and also from plutons of the rising batholith. The miogeosynclinal basins were filled with material derived from the continental hinterland.
The eugeosyncline was deformed during the Upper Albian and the Coastal Batholith was emplaced during the Upper Cretaceous while sedimentation continued in the miogeosyncline. Deformation of the miogeosyncline occurred during the Palaeocene.
Aubouin's distinction of Andean from Alpine chains is confirmed. Andean chains are characterised by andesite volcanics and tonalite batholiths, whereas Alpine chains contain ophiolite belts and sedimentary flysch. The differences may reflect their different tectonic setting, the Andes having developed under a convergent regime between a continent and a large ocean while the. Alpine chains may have evolved under a regime involving the opening and closing of small ocean basins between continents. It is suggested that andesite volcanics and tonalite batholiths are characteristic indicators of the subduction process at continental margins.
Conference Report
Mineralization associated with acid magmatism and other aspects of ore geology
Authors: Evans A. M. 
Published: December 2007

The first part of the title of this conference is also the title of an international group co-ordinating research in this field. This meeting was held at the request of the Group's British representatives and produced varied group of papers covering mineralization in both the volcanic and plutonic associations.
It had been hoped that Dr M. Štemprok would give an opening address but, as he was unable to be present, Dr Alan Bromley kindly stepped into the breach. In a very comprehensive survey of the field he commenced with the problem of the generation of granitic magmas particularly those associated with subduction zones, because at this plate juncture we often see a zoning of metallic deposits which suggests derivation of the metals from the subduction zone, with perhaps the rising granite magmas acting only as carriers. The metals probably move as complex halide ions with, perhaps for tin, the possibility of fluoride, liberated from the breakdown of apatite, being the carrier ion. Bromley emphasized the importance of manganese nodules as carriers of many metals down the subduction zones but not of tin and tungsten. He noted that in Cornwall, joints in mineralized areas are coated with much manganese and posed the question, 'Does manganese give a broad halo useful in exploration in such areas?'
Manganese nodules and the sediments of layer 1 of the oceanic crust could supply the metals of deposits in the zones nearest to the trenches. However, the genesis of tin and tungsten ores seems
Metallogenesis in the Japanese island arc system
Authors: Ishihara S. 
Published: December 2007

Ore deposits in the Mesozoic and Cenozoic orogenic belts of the Japanese island arc system consist essentially of stratabound, vein and skarn types. The stratabound base-metal deposits, which are the main source of copper, are divided into the lead-free, chalcopyrite-pyrite, Besshi-type, which occur mainly in glaucophane schists (metamorphosed basaltic pyro-clastic rocks) of the Sanbagawa belt, and the lead-bearing, polymetallic, massive sulphide, Kuroko-type, associated with rhyolite extrusion. Both types are regarded as having been formed syngenetically in a submarine environment. Vein-type deposits are widely distributed and economically the most important for metals, containing more than 50 per cent of the available tin, tungsten, molybdenum, gold, silver and manganese. The ore deposits are genetically related to either 'geosynclinal basalt' or an andesite-dacite-rhyolite and plutonic association of island arc magmatism. Special attention is given to deposits of plutonic affinity.
Most Japanese plutons are granitoids. Ore deposits associated with Cretaceous-Palaeogene granitoids in southwest Japan constitute two metallogenic provinces, characterised by W-Sn-Cu and Mo-Pb-Zn veins and skarns. Northeast Japan shows a similar, but reversed, zoning, with no tin. Miocene granitoids in southwest Japan are accompanied by tin and some copper mineralization. The Japanese granitoids consist of approximately equal proportions of magnetite-series and ilmenite-series rocks. The magnetite-series is thought to be derived from a parental magma generated from mafic igneous rocks of the upper mantle—lower crust and related to major subduction. The ilmenite-series, with which tin deposits may be associated, is ascribed to magma originating in the lower crust from sedimentary, metamorphic and granitoid rocks. These magma types appear to be the most important factors in producing the various metallogenic provinces in Japan.
Late Mesozoic sedimentary rocks of Fuerteventura, Canary Islands: Implications for West African continental margin evolution
Authors: Robertson A. H. F. , Stillman C. J. 
Published: December 2007

The basal complex of Fuerteventura, inner Canary Islands, includes a thick sequence (c. 1.5 km) of early Cretaceous terrigenous and calcareous clastic sediments and black shales. Previously interpreted as shallow-water deposits, these rocks are reinterpreted as part of a deep-sea fan on the rifted West African continental margin. Sediments were derived from ancient crystalline massifs inland, and from a probable collapsed carbonate platform located offshore.
Stable passive margin conditions ended in the Albian with onset of calcareous pelagic sedimentation coupled with major localised uplift. After a hiatus, alkalic submarine volcanic rocks were extruded, followed by folding, then a substantial sheeted-dyke complex was intruded from late Eocene to mid-Miocene. After renewed uplift and peneplanation of the Basal Complex, Neogene plateau lavas were extruded.
Structural analysis of Fuerteventura rocks and regional comparisons, including IPOD data, show that from early Cretaceous to mid-Tertiary the island experienced successive phases of crustal uplift, compression and extension, possibly related to orogenic events in the High Atlas.
The San Andreas fault system through time
Authors: Crowell J. C. 
Published: December 2007

The active San Andreas fault system today lies at the splintered boundary between the Pacific and North American lithospheric plates, a tectonic arrangement that originated in California in the Oligocene. By late Miocene time sedimentary breccias derived from San Andreas scarps were being shifted laterally from their source areas. During the Pliocene the system extended from the Mendocino triple-junction to the head of the Gulf of California. The Big Bend in the San Andreas developed and the Transverse Ranges rose, in association with the opening of the Gulf of California.
The boundary between the Pacific and North American plates is wide and fragmented and during the late Cenozoic, the crust has yielded laterally by simple shear and deformed through pull-apart stretching and fault-block squeezing and uplift and rotation. Splay faults, such as the San Jacinto, Calaveras, and Hayward, branch from the main fault near constraining bends. The strewn out arrangement of displaced slices may account for displacements of 600 km on the northern San Andreas and only 300 km on the southern across a wide mobile boundary zone that has a total displacement exceeding 1000 km. Strike slip may also have occurred along faults parallel to the system in Cretaceous-Palaeocene times when the Kula Plate was moving laterally northwestward with respect to the North American Plate.
P-T conditions in the Moines of the Central Highlands, Scotland
Authors: Wells P.R.A. 
Published: December 2007

P-T conditions of regional Caledonian metamorphism recorded by calc-silicate assemblages in Moine rocks from the Central Highlands vary from 550°C, 7 ± 2 kbar, near Loch Laggan, to 670°C, 10 ± 2 kbar in the central Spey valley. The pressure conditions correspond to 30–35 km of tectonic cover in the Central Highlands during the metamorphic temperature maxima. These estimates place much of the Moines of the Central Highlands in the kyanite zone.
Spatial variations in estimated pressure conditions at comparable temperatures suggest differential initial tectonic cover thickness and/or differential erosion over the Caledonide orogen.
Numerical models of these alternative thermal regimes predict different P–T histories for the metamorphic rocks of the Central Highlands. Mineral assemblages exhumed by differential erosion, related to different cover thickness, record maximum temperature conditions at progressively earlier times with increasing recorded pressure. These time relations are reversed for differential erosion of initially uniform cover thickness. These results have general application to metamorphic rocks developed within zones of tectonic thickening.
Regional geochemical mapping and health in the United Kingdom
Authors: Thornton I. , Plant J. 
Published: December 2007

Geochemical atlases based on the analysis of sediments from surface tributary drainage have been published for Northern Ireland, and England & Wales; the data are smoothed by computer and show regional patterns for the distribution of 20 and 21 elements respectively. Atlases for parts of Scotland present point-source data for up to 25 elements in stream sediments; additional data have been obtained for pan concentrates and stream waters. Regional surveys to provide point-source information are continuing and it is intended that they will in due course cover the whole of the United Kingdom.
Research has been successfully undertaken into the applications of geochemical maps to problems of plant and animal health and production, and maps are currently used to delineate areas of potential trace element deficiency and heavy metal excess, particularly where problems may be of a sub-clinical nature. Applications to human health are illustrated with examples of metal anomalies in old mining areas in Derbyshire (Pb) and Somerset (Cd, Zn). Geochemical atlases continue to provide valuable sources of multi-element data for area selection in food, water and medical surveys, and comprise useful base-line information for epidemiological studies.
Manganese nodules and other ferromanganese oxide deposits from the Indian Ocean
Authors: Cronan D. S. , Moorby S. A. 
Published: December 2007

Ferromanganese oxide concretions from the Indian Ocean exhibit considerable mineralogical and chemical variation, often differentiated on a regional basis. Nodules richest in Mn, Ni, Cu and Zn are found in sub-equatorial basin areas, but enrichments of some of these metals also occur in nodules elsewhere, particularly where there is evidence of major biogenic contributions to their underlying sediments. Fe, CO and Pb are most enriched in concretions from sea-mounts and the mid-ocean ridge system, but also attain high values in some basin areas. Local variations in concretion composition have been found off southern Africa, and are due to both biological and continental influences.
There are several major controls on the compositions of the concretions. Source variations influence composition in that Mn, Ni and Cu show evidence of diagenetic enrichment in deposits after being cycled through the biogenic component of sediments, whereas, Fe, CO and Pb appear to be supplied mainly by normal seawater. Environmental influences, including bottom water characteristics, affect the degree of dissolution of biogenic remains and this affects the sediment type and the supply of metals to the deposits and also their mineralogy, which in turn affects trace metal uptake. In the Central Indian Basin, source and environmental influences combine to produce ‘ore grade’ nodules.