bluuebunny/crossref_metadata_2025_split huggingface dataset:
Isotopic evolution of the Lizard Complex
Authors: Davies G. R. 
Published: December 2007

An Sm-Nd mineral isochron from an olivine gabbro yields an age of 375 ± 34 Ma (MSWD = 0.006) which represents the formation age of the Lizard Igneous Complex. Associated dolerite dyke suites have ɛ
Nd375
values between +8.9 and +11.7 and record derivation from a recently trace element-enriched, but heterogeneous, source region.

The petrology and Sm-Nd isotope systematics of the Lizard peridotites record the local infiltration of a magma. Significantly, the Sm-Nd isotope systematics of the ‘metasomatized’ peridotites are the same as calculated sources of the dolerite dyke suites: their sources are probably equivalent at depth.
Finally, the magmatic evolution of the Lizard Complex is likened to the initial development of the Red Sea, with early trace element-enriched volcanism followed by MORB-Iike activity.
MOIST and the continuity of crustal reflector geometry along the Caledonian-Appalachian orogen
Authors: Brewer J. A. , Smythe D. K. 
Published: December 2007

New aspects of the deep structure of the Scottish Caledonides are revealed by the Moine and Outer Isles deep seismic reflection traverse (MOIST). The Caledonian foreland is underlain by an easterly-dipping, strongly reflecting surface cutting through the Moho and traceable to more than 45 km depth. Thrusts within the foreland basement and Caledonian orogen have been reactivated as normal faults bounding half-grabens filled with sediments of late Palaeozoic to Mesozoic age. The Moine Thrust, which carries rocks of the orogen over Lewisian foreland, dips at 20–25° to the E on MOIST, and is either: (a) the westernmost of a series of easterly-dipping reflections (thrusts) which flatten or terminate at 17–20 km depth, or (b) a thrust lying further E which structurally overlies these easterly-dipping reflectors. By comparison with easterly-dipping reflections on COCORP lines in the northern and southern Appalachians the latter interpretation is preferred, implying that many of the easterly-dipping reflections on MOIST correspond to off-shelf metasedimentary rocks, with slivers of basement, stacked and imbricated against the Lewisian basement edge. Regional seismic refraction and conductivity data from northern Scotland suggest that regions of the Caledonian orogen have lower mid-crustal velocity gradients and higher conductivities than the foreland, which might be explained by this interpretation of the easterly-dipping reflections.
Despite similarities in crustal reflector geometries, there are important differences between the MOIST and COCORP lines, including (1) a remarkably continuous, relatively horizontal Moho seen on MOIST data at about 25 km depth, and (2) the sedimentary basins offshore from northern Scotland which have formed by reactivation under crustal extension of the easterly-dipping thrusts. Furthermore, it is probable that the easterly-dipping reflectors in these areas of the MOIST and COCORP lines were formed at different times in the early Palaeozoic.
Fossils and tectonics
Authors: FORTEY R. A. , COCKS L. R. M. 
Published: December 2007

‘Fossils can date rocks’ is a statement recognizable by all earth scientists, but all too many geologists stop there in their appreciation of how palaeontology can help them to solve their other problems, or of how to use it as an independent check of hypotheses reached by other methods. This thematic of papers, deriving from the Geological Society meeting organised on the same topic in February 1985, aims to help bridge the divide that exists between palaeontologists on the one hand and earth scientists of many other disciplines on the other.
The histories of geology and palaeontology were intimately intertwined until the last two or three decades. More recently, the sheer proliferation of literature and the growth of geological subdisciplines have perhaps displaced palaeontological data from the main stream of geological reasoning. Newer fields have apparently offered an objectivity that the deliberations of the palaeontologist may have seemed to lack. During this time British palaeontologists have established their own very successful Association, but the growth of palaeobiology and other aspects of the science may still obscure the geological roots of the subject, or its applicability to current problems of, for instance, structural geology. In short, the role of fossils has often tended to become a routine service in the dating of rocks—or just one of a series of potential‘event stratigraphic criteria’.
We regard this as unfortunate. The fossil record has several advantages which make it particularly important in the interpretation of structural and geotectonic problems: 1. The information from
Conodont palaeobiogeography and thermal maturation in the Caledonides
Authors: ALDRIDGE R. J. 
Published: December 2007

Conodont elements are important in biostratigraphy, in palaeoenvironmental and palaeobiogeographical analyses, and in assessing the thermal history of Lower Palaeozoic strata throughout the Caledonian belt. The differentiation of Ordovician conodont faunas into the North Atlantic and North American Midcontinent provinces is not closely comparable with the provincial patterns shown by other faunal groups and does not relate clearly to criteria for recognizing continental separation across the Iapetus Ocean. Some species associations adapted to cool, normal marine waters were able to cross the ocean at the time of its presumed maximum extent.
The colours of conodont elements reflect the thermal history of strata and can be used in studies of low-grade metamorphism. In S. Wales, for example, metamorphic temperatures indicated by conodont colour are too high to he accounted for by simple burial beneath the known stratigraphical overburden under normal heat flow conditions. Elsewhere, conodont colour trends also serve to constrain and test models of metamorphism that involve sedimentary burial in subsiding basins, tectonic burial under nappes, or the thermal effects of intrusions.
Lineaments and basement domains: an alternative view of Dalradian evolution
Authors: FETTES D. J. , GRAHAM C. M. , HARTE B. , PLANT J. A. 
Published: December 2007

This paper examines the evidence for basement structures of predominantly non-Caledonoid trend which appear to have influenced the development of the Dalradian belt in Scotland. A number of domains or blocks separated by dominantly trans-Caledonoid lineaments are recognized on the basis of geophysical, stratigraphical and geochemical patterns. These are thought to reflect fault-bounded depositional basins controlled by basement lineaments during the extensional phases of the Caledonian 'orogeny'. In addition the recognition of a number of these domains and lineaments in the structural, metamorphic and igneous data-sets for the Dalradian belt, shows the continuing influence of these basement controlled features throughout the compressional and uplift phases of the orogenesis.
A possible tectonic model is proposed which envisages the depositional basins forming in a setting dominated by Caledonoid trending transcurrent faults and a major pull-apart basin forming on a trans-Caledonoid axis.
The granites of the Southeast Asian Tin Belt
Authors: COBBING E. J. , MALLICK D. I. J. , PITFIELD P. E. J. , TEOH L. H. 
Published: December 2007

Four granite provinces have been delineated each with its own distinctive pattern of mineralization.
1. The Main Range Province. Endogenous greisen-bordered vein swarms of cassiterite and wolframite.
2. The Eastern Province. Magnetite–cassiterite skarns ± base metal sulphides with antimony in Thailand.
3. The Western (Peninsular Thailand–Burma) Province. Endogenous greisen-bordered vein swarms and pegmatites of cassiterite and wolframite.
4. The North Thailand Migmatitic Province. Endogenous vein and skarn replacement scheelite and fluorite deposits with some tin and local antimony.
In all provinces, but particularly in the Main Range, granitoids designated as two-phase variants have been recognized where xenocrysts and xenoliths of coarse, primary texture granite are enclosed in, and corroded by an invasive, equigranular quartzo–feldspathic matrix. These rocks form an essential part of the granite sequence in all provinces and have probably resulted from the infiltration and disruption of the host granite by late stage magmatic fluids.

Whole rock geochemistry from Peninsular Malaysia shows that the granites from the Main Range and Eastern Provinces comprise two contrasted suites which correspond approximately to the I and S-type categories advocated by Chappell & White (1974). In addition it is shown that individual plutons within batholiths in the two provinces have distinctive geochemical parameters. Variation diagrams of plutons having the intrusive sequence primary texture granite—two-phase granite—microgranite show linear trends with increasing SiO
2
, Na
2
O, Rb, W, Sn and U, and decreasing Sr, Ba, Th and all other major elements.
The geochemistry and petrology of an alkaline lamprophyre sheet intrusion complex on Maio, Cape Verde Republic
Authors: FURNES H. , STILLMAN C. J. 
Published: December 2007

The Atlantic island of Maio in the Cape Verde archipelago has a Basement Complex of Mesozoic and Tertiary age which is invaded by an intense swarm of sheet intrusions ranging in age from c. 16 to 8 Ma. These cut an alkaline ultramafic, mafic and felsic plutonic complex (Central Igneous Complex) and its host, a segment of Jurassic ocean floor with pillow lavas and abyssal sediments. The Basement Complex is dissected and unconformably overlain by a sequence of lavas of basanitic and nephelinitic composition.
The sheet intrusions comprise sills and dykes of alkaline lamprophyre, many of which are aphyric or sparsely porphyritic. Phenocrysts are predominantly clinopyroxene, with smaller amounts of olivine and Ti-magnetite. Microphenocrysts are kaersutite, apatite and biotite. The groundmass is dominated by potassium feldspar and analcime. Calcic plagioclase is extremely rare. Chemically the intrusions are basanitic, with major and minor element compositions directly comparable with the Neogene and Pleistocene basanitic lavas which cap the island. Calculations based on observed phenocryst phases suggest that the liquids involved in the crystallization of the sheet intrusions may have been derived by crystal fractionation from a range of basanitic parents. These were similar to those from which the later lavas were generated, but modified to some extent by variable water-rock interactions enhanced by trapped volatiles.
Coal and coal-bearing strata: problems and perspectives
Authors: SCOTT A. C. 
Published: December 2007

For the past 15 years oil, of all the fossil fuels, has been the most prominent in both geological and non-geological literature. Significant progress has been made on many aspects, especially in exploration by employing interdisciplinary approaches to make scientific and economic gains. Technical advances have allowed exploration to move into more hostile geographical areas. The effect on research of this increased exploration effort has been to stimulate new interpretations in several areas of geology, especially in sedimentology, tectonics, geophysics and geochemistry.
Coal has, to some extent, remained a poor relation. Effort has been directed to more technical aspects of production and utilization rather than in the investigation of more fundamental aspects concerning its origin. In spite of this there has been significant progress in several aspects of coal geology over the past 15 years. In addition, new geographical areas are opening up for exploration, most notably China, Australia, western North America and Indonesia. The time is right, therefore, to highlight recent advances in coal research.

In 1968, following an inter-university student conference,
D.
G. Murchison and T.
S.
Westoll edited an important volume on
Coal and Coal-bearing Strata
which synthesized several important aspects of coal research. Soon after this, the second edition of Stach’s classic
Textbook
of
Coal Petrology
was published (

Stach
et al.
1975

, now in its third edition). Much is owed to work of M. & R. Teichmiiller on coalification and its uses. The recent upsurge of interest in coal geology is indicated by the publications of
Plesiosaur locomotion
Authors: HALSTEAD L. B. 
Published: December 2007

Plesiosaurs are unique in being the only underwater fliers with four ‘wings’, and how the two pairs worked in relation to one another is a matter of some controversy. Newman's hypothesis of porpoising seems to provide a possible solution.
Any discussion of plesiosaur locomotion must take into account the different modes of plesiosaur life: the long-necked forms were fish-eating surface paddlers and the short-necked were diving cephalopod feeders.
Petrology of two Tertiary oil shale deposits from Queensland, Australia
Authors: Gibson P. J. 
Published: December 2007

Sediments from two Queensland Tertiary lacustrine oil shale deposits, the Lowmead and Duaringa Basins, have been petrologically characterized from standard X-ray powder diffraction analyses, backscattered electron microscopy and electron microprobe data. The results presented illustrate the potential of backscattered electron imagery for the study of diagenesis in fine-grained, organic-rich sediments.
The Lowmead Formation consists of lamosites, claystones and brown coals deposited in freshwater lacustrine and fringing peat-swamp environements. Their dominant constituents are kaolinite and quartz, with opaline silica and siderite important as eogenetic phases. Despite its similar geological setting, the Duaringa Formation contains a more varied lithological assemblage with less organic matter being preserved. Freshwater lacustrine claystones and lamosites are interbedded with carbonate sediments deposited during periods of saline/alkaline conditions in the lake. Within these carbonate sediments, major growth of eogenetic mineral phases occurred, principally dolomite and analcite. As in the Lowmead Basin, siderite is an important eogenetic phase in the Duaringa Formation. Two types of sideritic ironstone band occur throughout both basins; sphaerosiderites within claystone/coal sediments and fine-grained bands of siderite within lamosites. The bulk mineralogy of the siliciclastic detritus shows no significant trends with depth within either basin.
Early Ordovician alluvial fan deposits of the Marmul oil field, South Oman
Authors: HEWARD A. P. 
Published: December 2007

Fine grained shaly sands of the Mahwis Formation (Haima Group) form one of the reservoir intervals of the Marmul field. Six lithofacies can be distinguished from cores: shale clast conglomerates, trough cross-stratified sands, horizontally stratified sands, massive sands, rippled sands and interbedded shales and sands. Horizontally stratified sands make up 45% of the cored reservoir. Two scales of fining upward sequence occur. Small sequences are 0.3-1.5 m thick and are interpreted as sheetflood deposits on the distal portions of semi-arid alluvial fans. The larger sequences are 25-50 m thick, can be correlated on well logs fieldwide, and probably represent periodic tectonic rejuvenation and erosional lowering of the sediment source area.
It is interpreted (from regional correlation, sediment provenance, and a knowledge of possible source areas) that the alluvial fans were predominantly sandy, had radii of several tens of kilometres and formed an extensive apron bordering a highland area which lay to the southeast. The thinly bedded and shaly character of these sheetflood sands causes problems of petrophysical log evaluation and hence oil-in-place estimation. Reservoir quality is related to lithofacies occurrence and variation in grain size. The large-scale fan sequences correspond to an upward decrease in porosity and permeability and form useful subdivisions for field-scale correlation and reservoir prediction.
A return to William Smith
Authors: Fyfe William Sefton 
Published: December 2007

I was
deeply honoured
when the Geological Society invited me to give the William Smith Lecture for 1970. It was an invitation rather easy to accept but when I contemplated the work of William Smith himself, I began to feel more and more inadequate for the task. What could a chemical-geologist say that might do honour to a man who was one who established geology as a rigorous science and who founded stratigraphy and geological mapping, the heart of all geology?

I think that as most of us grow a little older, we find that our new thoughts or the stage of thinking we have reached is often only that of workers long ago. For this reason when I pondered the subject of this lecture I looked a little at some of the writing of Smith himself and found again that my own present trend of thinking and plans for future working, were simply echoes from Smith. This man, who as Lyell states was ‘unassisted by advantage of wealth or station in society’ could have been the author of many parts of our present so-called ‘forward looks’.
I think it is perhaps justifiable here to quote a few of William Smith’s remarks from the 1815 memoir which accompanied his map of the strata of England:
“The wealth of a country primarily consists in the industry of its inhabitants, and in its vegetable and mineral productions; the application of the latter of which to the purposes of manufacture, within memory, has
The Badenian evaporite basin of the northern Carpathian Foredeep as a model of a meromictic selenite basin
Authors: Bąbel M. , Bogucki A. 
Published: December 2007

AbstractThe hydrography and brine flow patterns in the Middle Miocene (Badenian) evaporite basin of the northern Carpathian Foredeep (in Ukraine, Poland and the Czech Republic) are reconstructed based on studies of the peculiar, conformably oriented, bottom-grown gypsum crystals present in the selenite deposits along the basin margin. The crystal apices are turned in a similar horizontal direction that is interpreted as the product of consistent flow of the bottom brines during crystal formation. Similarly the regular millimetre-scale growth zoning in these crystals presumably reflects the annual stratification-mixing pattern in the brine column typical of monomictic basins. In the central, deeper parts of the basin deposition was dominated by Na-chloride, and the selenitic facies are lacking. These central areas are interpreted as being meromictic during the oriented selenite deposition. The permanent pycnocline separated a mixolimnion, at the surface, from an anoxic (euxinic) monimolimnion, at the bottom, where direct evaporative crystallization of gypsum was not possible. The mixolimnion, which extended far onto the shallow margin of the basin, showed only a seasonal (annual) pycnocline and monomictic hydrography. Oriented selenites grew just in this mixolimnetic marginal zone, under predominantly counterclockwise (cyclonic) flow.
Evidence of vanished evaporites in Neoarchaean carbonates of South Africa
Authors: Gandin A. , Wright D. T. 
Published: December 2007

Abstract
A detailed sedimentological and petrographic analysis of the Neoarchaean Campbellrand and Malmani carbonates of South Africa provides evidence that collectively indicates the former existence of evaporites and the early replacement of primary sulphate deposits by calcite. Diagenetic disruption of sedimentary structures, solution collapse breccias, cross-cutting relationships, corrosion surfaces, pseudomorphs of displacive nucleation cones, flowage and nodular structures are all characteristic of evaporites and their ductile behaviour. In thin section, rosettes of length-slow chalcedony around the heads of the silicified stromatolites also testify to the former presence of sulphates. Calcite, in the unusual form of herringbone/flamboyant spar in ‘cuspate’ and nodular facies, may preserve the fold shapes of enterolithic gypsum, picked out by deformed trails of degraded organic matter and dolomitized clusters of filaments. Subvertical columns of compressed organic material in a matrix of herringbone/flamboyant calcite appear to be the result of squeezing and compression between adjacent sulphate nodules. Carbonate replacement of evaporites was largely driven by bacterial sulphate reduction in sapropels and microbialites during early diagenesis. The petrographic evidence indicates that the replacive herringbone/flamboyant calcite precipitated after enterolithic and nodular structures formed, the sulphate having been used up before the enclosed organic material was totally consumed.
A comparison between deterministic and stochastic fault seal techniques
Authors: Dee S. J. , Yielding G. , Freeman B. , Bretan P. 
Published: December 2007

Abstract
Traditionally, the analysis of fault seal has been purely deterministic or a combination of deterministic and stochastic methods. In a deterministic model, prediction of the locations of reservoir overlaps is made from the static model of the reservoir horizon and fault geometry. The principal aim is to map faulted reservoir overlaps and determine their sealing character. This is usually performed using a predictive algorithm such as the shale gouge ratio (SGR) that relates the shale content of the formations that have moved past a point on the fault zone to the sealing capacity of the fault rock.
Deterministic fault seal studies are sensitive to the uncertainties associated with mapping of horizons in proximity to faults and the inherent uncertainty in a static fault interpretation in both position and fault zone complexity. Uncertainty in the static structure model can be addressed by convolving uncertainty in throw magnitude with juxtapositions at the fault. However, this does not address the uncertainty in the distribution of reservoirs on either side of the fault. With stochastic models multiple realizations of the stratigraphy can be tested. Stochastic models capture the uncertainty in the position of the reservoir at the fault by allowing multiple realizations of stacking geometries, where the principal assumption is that these stacked reservoir zones are laterally continuous covering the entire likely fill area.
Despite the conceptual differences between these two approaches to fault seal analysis, comparison of the predictions they make on the Ling Gu field shows a surprising degree of conformity. The cut-off used to determine the number of sand and shale beds in the stochastic workflow appears to account for seal by fault zone materials, since a conservative cut-off implies fewer sand beds with lower probability of leak and correlates with more shale in the section and higher SGR values.