bluuebunny/crossref_metadata_2025 huggingface dataset:
Standardised method of selecting surgical approaches to benign parapharyngeal space tumours, based on pre-operative images
Authors: Kanzaki S , Nameki H
Published: July 2007

Many approaches to the parapharyngeal space have been reported. However, few reports describe parapharyngeal space tumours and the best surgical approach to these tumours. We retrospectively examined the surgical approaches we used to resect 22 parapharyngeal space tumours. In order to determine the best surgical approach for each tumour, we first subdivided the parapharyngeal space into six compartments, based on anatomical landmarks seen on computed tomography and/or magnetic resonance imaging scans. We then determined the location of each tumour relative to these six parapharyngeal space compartments. In our series of cases, we found that large tumours spanning the superior portion of the parapharyngeal space could be completely removed through a skull base approach. To remove a large tumour in the middle and inferior portion of the parapharyngeal space, a transparotid approach was the most suitable. Finally, a tumour in the inferior portion of the parapharyngeal space was best accessed through a transcervical approach.
Fazlul Huq, Region and Religion in Bengal: The Forgotten Alternative of 1940–43
Authors: AIYAR SANA
Published: July 2007

In the wake of the Government of India Act of 1935, provincial politics emerged as a challenge to the authority and legitimacy of all-India, centralised political parties. While the Congress and the Muslim League set up a binary opposition between secular and religious nationalism, provincial politicians refused to succumb to the singularity of either alternative. Partition historiography has been concerned with the interplay of national and communal ideologies in the 1940s, overshadowing this third trajectory of regional politics that was informed by provincial particularities. This article traces a short-lived alternative that emerged in Bengal between 1940 and 1943 under the premiership of Fazlul Huq. Huq produced a peculiar form of identity politics that appealed not only to religious sentiment but also to regional loyalty that cut across the religious divide. Significantly, he did so without resorting to secular claims. By challenging Jinnah's claim to being the sole spokesman of Muslims in India and highlighting the different concerns of a province with a Muslim majority, Huq reconciled the twin identities of religion and region within the same political paradigm, and foreshadowed the emergence of Bangladesh in 1971.
The Parieto-Frontal Integration Theory (P-FIT) of intelligence: Converging neuroimaging evidence
Authors: Jung Rex E. , Haier Richard J.
Published: July 2007

“Is there a biology of intelligence which is characteristic of the normal human nervous system?” Here we review 37 modern neuroimaging studies in an attempt to address this question posed by Halstead (1947) as he and other icons of the last century endeavored to understand how brain and behavior are linked through the expression of intelligence and reason. Reviewing studies from functional (i.e., functional magnetic resonance imaging, positron emission tomography) and structural (i.e., magnetic resonance spectroscopy, diffusion tensor imaging, voxel-based morphometry) neuroimaging paradigms, we report a striking consensus suggesting that variations in a distributed network predict individual differences found on intelligence and reasoning tasks. We describe this network as theParieto-Frontal Integration Theory(P-FIT). The P-FIT model includes, by Brodmann areas (BAs): the dorsolateral prefrontal cortex (BAs 6, 9, 10, 45, 46, 47), the inferior (BAs 39, 40) and superior (BA 7) parietal lobule, the anterior cingulate (BA 32), and regions within the temporal (BAs 21, 37) and occipital (BAs 18, 19) lobes. White matter regions (i.e., arcuate fasciculus) are also implicated. The P-FIT is examined in light of findings from human lesion studies, including missile wounds, frontal lobotomy/leukotomy, temporal lobectomy, and lesions resulting in damage to the language network (e.g., aphasia), as well as findings from imaging research identifying brain regions under significant genetic control. Overall, we conclude that modern neuroimaging techniques are beginning to articulate a biology of intelligence. We propose that the P-FIT provides a parsimonious account for many of the empirical observations, to date, which relate individual differences in intelligence test scores to variations in brain structure and function. Moreover, the model provides a framework for testing new hypotheses in future experimental designs.
Intelligence? What intelligence?
Authors: Colom Roberto
Published: July 2007

Neuroimaging evidence, both within and between research strategies, is largely heterogeneous. This results from the way the construct of interest (i.e., intelligence) is measured. Every single available measure comprises several cognitive abilities, although the so-called g factor is always present. Here I suggest that studies must always control for this empirical fact to arrive at solid conclusions.
Linear and nonlinear absolute phase effects in interactions of ulrashort laser pulses with a metal nano-layer or with a thin plasma layer
Authors: Varró S.
Published: July 2007

It has been shown that in the scattered radiation, generated by an ultrashort laser pulse impinging on a metal nano-layer, non-oscillatory wakefields appears with a definite sign. The magnitude of these wakefields is proportional to the incoming field strength, and the definite sign of them is governed by the cosine of the carrier-envelope phase difference of the incoming pulse. When we let such a Wakefield excite the electrons of a secondary target (say an electron beam, a metal surface or a gas jet), we can obtain 100 percent modulation in the electron signal in a given direction. This scheme can serve as a basis for the construction of a robust linear carrier-envelope phase difference meter. At relativistic laser intensities, the target is considered as a plasma layer in vacuum produced from a thin foil by a prepulse, which is followed by the main high-intensity laser pulse. The nonlinearities stemming from the relativistic kinematics lead to the appearance of higher-order harmonics in the scattered spectra. In general, the harmonic peaks are downshifted due to the presence of an intensity-dependent factor. This phenomenon is analogous to the famous intensity-dependent frequency shift in the nonlinear Thomson scattering on a single electron. In our analysis, an attention has also been paid to the role of the carrier-envelope phase difference of the incoming few-cycle laser pulse. It is also shown that the spectrum has a long tail where the heights of the peaks vary practically within one order of magnitude forming a quasi-continuum. Fourier synthesizing the components from this plateau region attosecond pulses has obtained.
Statistical model of radiation damage within an atomic cluster irradiated by photons from free-electron-laser
Authors: Ziaja B. , Weckert E. , Möller T.
Published: July 2007

Here we report on the present status of our project on statistical modelling of charge dynamics within irradiated samples. Boltzmann statistical approach to model the radiation damage in samples irradiated by FEL photons is tested in a study case of a spherically symmetric xenon cluster. Qualitative agreement between the model predictions and the experimental data is found. The results obtained demonstrate the potential of the statistical method for describing the non-equilibrium dynamics of samples exposed to FEL radiation.
Temporal compression by stimulated Brillouin scattering of Q-switched pulse with fused-quartz and fused-silica glass from 1064 nm to 266 nm wavelength
Authors: Yoshida H. , Fujita H. , Nakatsuka M. , Ueda T. , Fujinoki A.
Published: July 2007

We have designed a compact solid compressor by stimulated Brillouin scattering (SBS), which consists of two right angle prisms and a fused silica glass block. A 13–16 ns Nd:YAG laser pulse has been temporally compressed to 1 ns or less phase conjugation pulse in a fused-quartz and fused-silica glass at four different wavelengths. Maximum reflectivity of SBS was 90–95% without damage. The brightness of the compressed pulse was about ten-fold higher than that of the incident pulse. Damage-free operation using fused quartz glass as a better phase conjugation material could lead to the construction of a more compact, laser-diode-pumped, and all-solid-state laser system.
The status of Sus giganteus Falconer & Cautley, 1847 (Mammalia: Suinae) from the Indian Subcontinent
Authors: Pickford Martin
Published: July 2007

A re-examination of the lectotype of Sus giganteus Falconer & Cautley, 1847, reveals that it is a suine, as originally thought by its discoverers, and not a tetraconodont as recently published. It may belong to the genus Propotamochoerus as proposed by Azzaroli in 1989. This reassessment radically modifies tetraconodont systematics published recently by Van der Made (1999).
Petrogenesis of Mesoproterozoic (Subjotnian) rapakivi complexes of central Sweden: implications from U–Pb zircon ages, Nd, Sr and Pb isotopes
Authors: Andersson U. B. , Neymark L. A. , Billström K.
Published: July 2007

U-Pb zircon geochronology of Mesoproterozoic (Subjotnian) rapakivi complexes in central Sweden yields: 1526 ± 3 Ma (Mullnäset), 1524 ± 3 Ma (Mårdsjö), 1520 ± 3 Ma (Nordsjö) and 1497 ± 6 Ma (Rödön). Together with complexes further S in Sweden, they constitute the westernmost, youngest (1·53−1·47 Ga) belt of rapakivi magmatism in the Fennoscandian shield.

The low initial εNd values (−8·9 to −4·8) of all studied Subjotnian basic, intermediate and silicic rocks, require an input from an old (Archaean) low-radiogenic source component, as evidence for Palaeoproterozoic protoliths in the age range 2·5−2·1 Ga is lacking in this region. Crustal, early Svecofennian + Archaean (roughly 30−40%) sources are suggested for the Subjotnian A-type granites and syenites, where the granites derive from undepleted, granodioritic, and the syenites from monzodioritic (±depleted crustal) protoliths. The basic rocks originate from a depleted mantle acquiring the enriched Nd isotopic signatures during interaction with an Archaean lower crust (20−40%), largely depleted after rapakivi melt extraction. Pb isotope data from feldspars (207Pb/204Pb to 15·018−15·542) support the presence of Archaean components in the magmas.

The results indicate that an Archaean basement is underlying relatively wide areas of Svecofennian formations in central Sweden. This old basement section was most likely rifted off the Archaean craton in the NE in Palaeoproterozoic times.
Silurian and earliest Devonian birkeniid anaspids from the Northern Hemisphere
Authors: Blom H. , Märss T. , Miller C. G.
Published: July 2007

The sculpture of scales and plates of articulated anaspids from the order Birkeniida is described and used to clarify the position of scale taxa previously left in open nomenclature. The dermal skeleton of a well-preserved squamation of Birkenia elegans Traquair, 1898 from the Silurian of Scotland shows a characteristic finely tuberculated sculpture over the whole body. Rhyncholepis parvula Kiær, 1911, Pterygolepis nitida (Kiær, 1911) and Pharyngolepis oblonga Kiær, 1911, from the Silurian of Norway show three other sculpture types. Northern Hemisphere disarticulated scales and plates are described here, supporting a new anaspid taxonomy that includes both articulated and disarticulated material. The diversity, distribution, evolutionary trends and biostratigraphy of anaspids are described in the context of this new taxonomy, which includes six families (two are new) subdivided into 16 genera (10 are new) and 22 species (15 are new).

New taxa among Birkeniidae Traquair, 1898 are Birkenia robusta sp. nov. and Hoburgilepis papillata gen. et sp. nov.. Rhyncholepididae Kiær, 1924 includes Rhyncholepis butriangula sp. nov., Silmalepis erinacea gen. et sp. nov., Vesikulepis funiforma gen. et sp. nov., Maurylepis lacrimans gen. et sp. nov., and the previously described Schidiosteus mustelensis Pander, 1856 and Rytidolepis quenstedtii Pander, 1856. Tahulalepididae fam. nov. is represented by Tahulalepis elongituberculata gen. et sp. nov. and the revised T. kingi (Woodward, 1947). Septentrioniidae fam. nov. contains Septentrionia lancifera gen. et sp. nov., S. mucronata gen. et sp. nov., S. dissimilis gen. et sp. nov., S. seducta gen. et sp. nov., Liivilepis curvata gen. et sp. nov., Spokoinolepis alternans gen. et sp. nov. and Manbrookia asperella gen. et sp. nov. The family level position of Ruhnulepis longicostata gen. et sp. nov. is uncertain. Pterygolepididae Obruchev, 1964 and Pharyngolepididae Kiær, 1924 remain monogeneric.
A chitinozoan biostratigraphy of the Upper Ordovician and lower Silurian strata of the Girvan area, Midland Valley, Scotland
Authors: Vandenbroucke Thijs , Verniers Jacques , Clarkson Euan N.K.
Published: July 2007

Forty-six samples, taken from the Upper Ordovician and lower Silurian strata of the Girvan district, Midland Valley of Scotland, yield moderately well-preserved and diverse assemblages of chitinozoans. The area was chosen to study the composition of the chitinozoan assemblages, rarely described before in Scotland, which lay at the south-eastern margin of the Laurentia palaeocontinent. These assemblages are compared with those of the same age on other palaeocontinents, representing a critical time when both the Iapetus and Tornquist oceans were closing, thus forming the Caledonide and associated orogens. It is possible to correlate the chitinozoan occurrences at Girvan with those of other parts of Laurentia (Quebec area), other palaeocontinents such as Baltoscandia (Sweden, Estonia), Avalonia (Wales, Brabant Massif) and some parts of Northern Gondwana (Saudi Arabia). For the lower Silurian, it is possible to correlate with the global chitinozoan biozonation, and a calibration between the chitinozoan occurrences and the graptolite biozonation of Girvan is established. Several levels within the Balclatchie, South Shore, Three Mile, Shalloch, Wood Burn, Lauchlan, Drumyork Flags and other formations are accurately dated.
Mandibles of rhizodontids: anatomy, function and evolution within the tetrapod stem-group
Authors: Jeffery Jonathan E.
Published: July 2007

The Rhizodontida (Pisces: Sarcopterygii) is a clade of predatory fishes from the Upper Devonian (Aztecia; ?Givetian of Antarctica) through to the Upper Carboniferous (Strepsodus; Moscovian of northern Europe and North America). They form the most basal plesion within the tetrapod stem-lineage. The mandibles were dominated by large symphysial tusks on the dentary. Not much else is known of the mandibles in primitive rhizodontids. However, later forms show several derived characters: the mandible is very deep dorsoventrally and narrow linguolabially; the coronoid fangs bear only a single fang and no other dentition; the Meckelian element was unossified, leaving the adductor fossa unfloored by bone; the prearticular produced a large dorsal process lingual to the adductor fossa, presumably for muscle attachment. These and other characters are discussed in the context of the evolution of the tetrapod stem-group.

The mandible appears to have been split into two functional units, one comprising the firmly sutured prearticular, coronoids and dentary, the other comprising the firmly sutured infradentaries. The connection between the two units was weak, suggesting a longitudinal intramandibular hinge. The possibility that this acted as a ‘torsion grip’ during feeding is discussed.
Adequacy of the Early Ordovician trilobite record in the southern Montagne Noire (France): biases for biodiversity documentation
Authors: Vizcaïno Daniel , Álvaro J. Javier
Published: July 2007

The litho- and biostratigraphical subdivisions of the Tremadocian-Arenigian succession of the southern Montagne Noire are hereby revised. The Lower Ordovician diversity patterns are estimated through statistical analysis of 27 families, 64 genera and 132 species of trilobites across nine interval zones; from bottom to top: the Proteuloma geinitzi, Shumardia (Conophrys) pusilla, Euloma filacovi, Taihungshania miqueli, Taihungshania shui landyranensis, Colpocoryphe maynardensis, Neseuretus (Neseuretus) arenosus, Apatokephalus incisus and Hangchungolithus primitivus zones. Maximum trilobite diversity occurred within the E. filacovi and A. incisus zones, alternating with two sharp declines (S. (C.) pusilla and T.shui landyranensis zones), in both cases drastically related to transgressive-regressive trends. Trilobites attained their highest diversity in muddy outer-platform settings, decreasing in fine-grained sandstones and siltstones of shoreface environments, where trilobites could still be numerically abundant. Four major trilobite turnovers are recognised at the bottom of the P. geinitzi, S.(C.)pusilla, E. filacovi and T. shui landyranensis zones, in which survivors from previous intervals are not reported at specific level, and important generic replacements took place. Despite the relative incompleteness of the Lower Ordovician trilobite record, envisaged after analysing the high proportion of monotypic taxa and discontinuous ranges of some families, the trilobite record is representative enough to estimate diversity patterns, although a better understanding of the palaeoenvironmental control will greatly enhance biodiversity resolution.
A new specimen of Paleomerus hamiltoni (Arthropoda; Arachnomorpha)
Authors: Tetlie O. Erik , Moore Rachel A.
Published: July 2007

A fourth specimen of the enigmatic Lower Cambrian arthropod Paleomerus hamiltoni is described from the Mickwitzia Sandstone of Sweden. The nature of the telson of P. hamiltoni was previously unknown and it has been assumed that the abdomen consisted of 12 segments, the posterior-most being elongate and tapering. This new material constitutes a mould of the entire animal and a cast of the posterior-most abdominal segment and telson, proving that the abdomen consists of 11 segments and a short, tapering telson, which was previously misinterpreted as the twelfth abdominal segment. The presence of 11 abdominal segments in P. hamiltoni eliminates significant diff erences between it and Strabops thacheri, supporting assignment to Strabopidae and rendering the family Paleomeridae redundant.
A redescription of Chasmataspis laurencii Caster & Brooks, 1956 (Chelicerata: Chasmataspidida) from the Middle Ordovician of Tennessee, USA, with remarks on chasmataspid phylogeny
Authors: Dunlop Jason A. , Anderson Lyall I. , Braddy Simon J.
Published: July 2007

The type material of Chasmataspis laurencii Caster & Brooks, 1956 (Chelicerata: Chasmataspidida) from the Middle Ordovician (Tremadoc to Caradoc) of Sevier County, Tennessee, USA, is redescribed, and comparisons are drawn with recently discovered Devonian chasmataspids from Scotland, Germany and Russia. The depositional setting of the C. laurencii fossils is reinterpreted as an ash fall into shallow marine/tidal sediments. Chasmataspis laurencii confirms the presence of 13 opisthosomal segments in Chasmataspidida, a character of unresolved polarity. The phylogenetic position ofC. laurencii is difficult to resolve. A monophyletic Chasmataspidida has one convincing autapomorphy in the nine-segmented postabdomen, but C. laurencii shares a number of characters with xiphosurans (i.e. cardiac lobe, pre-abdomen with axial region, biramous and chelate limbs), while the Devonian taxa more closely resemble eurypterids (i.e. through pediform limbs and a genital appendage). Earlier interpretations of the respiratory system in C. laurencii appear unconvincing in the light of new evidence from Devonian forms with opisthosomal opercula. Resting impressions of a Chasmataspis-like animal from the Upper Cambrian Hickory Sandstone of Texas, USA, also appear to show evidence of opercula. These Texan fossils could represent the oldest record of Euchelicerata. Two chasmataspid families are recognised, and C. laurencii is placed in the monotypic Chasmataspididae Caster & Brooks, 1956, redefined here on the fused pre-abdominal buckler with an axial region and the narrow, elongate post-abdomen ending in a long, lanceolate telson.
The geology of the northern half of the Rhynie Basin, Aberdeenshire, Scotland
Authors: Rice C. M. , Ashcroft W. A.
Published: July 2007

A new geological map of the Early Devonian Rhynie Basin has been produced by traditional methods supplemented by trenching to bedrock and a ground magnetic survey. This shows that the basin margins are mostly fault-controlled and three trends are recognised: NE–SW, NNE–SSW and N–S. Three sets of open folds are distinguished with axial traces trending NE–SW, E–W and roughly NW–SE. The faults defining the basin margin and the folding may be related to basin formation within a regional strike-slip system of Early Devonian age.

The stratigraphic succession comprises three mappable units: a lower mixed unit of sandstones, shales, conglomerates and andesitic lava (>700 m), a middle unit of laminated grey shale and siltstone (>300 m); and an upper unit of laminated sandstones and shales (>300 m). These correlate with the Tillybrachty Sandstone and Quarry Hill Sandstone Formations (lower unit), and the Dryden Flags Formation (middle and upper units).

Small areas containing abundant chert float found outside the Rhynie SSSI may represent the surface expression of chert pods within the middle unit of laminated grey shale and siltstone, which also hosts the Rhynie cherts. The Windyfield cherts occur within the upper unit. No further centres of hydrothermal activity have been found in the northern half of the basin
Fluids and hydrothermal alteration assemblages in a Devonian gold-bearing hot-spring system, Rhynie, Scotland
Authors: Baron M. , Hillier S. , Rice C. M. , Czapnik K. , Parnell J.
Published: July 2007

Hydrothermal alteration at Rhynie, Aberdeenshire, Scotland, is concentrated along a fault zone, which juxtaposes surface deposits and the mineralised feeder zone to the Rhynie hotspring system. Mineralisation consists of breccias and veins filled with quartz, chert, calcite, K-feldspar and pyrite. Associated pervasive alteration comprises a high-temperature K-feldsparquartz-illite facies (formed at 250–350°C), a medium-temperature mixed layered illite/smectitequartz-K-feldspar-chlorite-calcite facies (formed at 150–200°C) and a low-temperature mixed layered illite/smectite-chlorite-calcite facies (formed at 100 to +150°C). The fluids responsible for mineralisation were mainly moderate- to high-temperature (Th =91–360°C), low-salinity (<0·2 to 2·9 wt.% NaCl eq.) H2O-NaCl-heated meteoric fluids comparable to modern and ancient hot-spring systems. The migration of these fluids was mainly restricted to a major fault zone bounding the Devonian basin. Fluids responsible for mineralisation, alteration and cementation elsewhere in the basin were low-temperature (Th 57 to 161°C), low- to high-salinity (<0·2 to 18 wt.% NaCl eq.) H2O-NaCl fluids, which resemble basinal brines.
A harvestman (Arachnida: Opiliones) from the Early Devonian Rhynie cherts, Aberdeenshire, Scotland
Authors: Dunlop Jason A. , Anderson Lyall I. , Kerp Hans , Hass Hagen
Published: July 2007

A harvestman (Arachnida: Opiliones) is described from the Early Devonian (Pragian) Rhynie cherts, Aberdeenshire, Scotland. Eophalangium sheari gen. et sp. nov. is the oldest known harvestman. The material includes both males and a female preserving, respectively, a cuticle-lined penis and ovipositor within the opisthosoma. Both these structures are of essentially modern appearance. The Rhynie fossils also show tracheae which are, again, very similar to those of living harvestmen. This is the oldest unequivocal record of arachnid tracheal respiration and indicates that E. sheari was terrestrial. An annulate, setose ovipositor in the female suggests that it can be excluded from the clades Dyspnoi and Laniatores, in which the ovipositor lacks such annulations. However, the penis shows evidence of two muscles, a feature of uncertain polarity seen in modern Troguloidea (Dyspnoi). The presence of median eyes and long legs excludes Cyphophthalmi, and thus, E. sheari is tentatively referred to the suborder Eupnoi. Therefore, this remarkable material is implicitly a crown-group harvestman and is one of the oldest known crown-group chelicerates. It also suggests an extraordinary degree of morphological stasis within the eupnoid line, with the Devonian forms differing little in gross morphology – and perhaps in reproductive behaviour – from their modern counterp
Spores of the Rhynie chert plant Horneophyton lignieri (Kidston & Lang) Barghoorn & Darrah, 1938
Authors: Wellman Charles H. , Kerp Hans , Hass Hagen
Published: July 2007

Detailed studies have been undertaken on in situ spores of the plant Horneophyton lignieri (Kidston & Lang) Barghoorn & Darrah, 1938 preserved in the Rhynie chert. It is concluded that mature spores are trilete, with proximal radial ribbing, and a distal ornament of coni. These spores are identical to Emphanisporites decoratus Allen, 1965, a widely reported and morphologically distinctive dispersed spore taxon. Emphanisporites decoratus is a common element of dispersed spore assemblages from throughout the stratigraphical sequence of the Rhynie outlier, and it is concluded that the dispersed spore taxon E. decoratus was produced by H. lignieri. The nature (reproductive biology, ecology and distribution) of H. lignieri is interpreted on the basis of evidence from the dispersed spore record from the Rhynie outlier and elsewhere. It is concluded that H. lignieri was a common and widespread plant of the Lower Devonian. It flourished in the unusual hot springs environment of the Rhynie chert because it was preadapted to do so, not because it was a highly specialized and adapted plant. Integrated evidence from the in situ and dispersed spore records permits a detailed consideration of the biology of the plant H. lignieri.
Fungi from the Rhynie chert: a view from the dark side
Authors: Taylor T. N. , Klavins S. D. , Krings M. , Taylor E. L. , Kerp H. , Hass H.
Published: July 2007

The exquisite preservation of organisms in the Early Devonian Rhynie chert ecosystem has permitted the documentation of the morphology and life history biology of fungi belonging to several major taxonomic groups (e.g., Chytridiomycota, Ascomycota, Glomeromycota). The Rhynie chert also provides the first unequivocal evidence in the fossil record of fungal interactions that can in turn be compared with those in modern ecosystems. These interactions in the Rhynie chert involve both green algae and macroplants, with examples of saprophytism, parasitism, and mutualism, including the earliest mycorrhizal associations and lichen symbiosis known to date in the fossil record. Especially significant are several types of specific host responses to fungal infection that indicate that these plants had already evolved methods of defence similar and perhaps analogous to those of extant plants. This suggests that mechanisms underlying the establishment and sustenance of associations of fungi with land plants were well in place prior to the Early Devonian. In addition, a more complete understanding of the microbial organisms involved in this complex ecosystem can also provide calibration points for phylogenies based on molecular data analysis. The richness of the microbial community in the Rhynie chert holds tremendous potential for documenting additional fungal groups, which permits speculation about further interactions with abiotic and biotic components of the environment.
The redox state of granitoids relative to tectonic setting and earth history: The magnetite–ilmenite series 30 years later
Authors: Ishihara Shunso
Published: July 2007

The redox state variation of orogenic granitoids along convergent plate margins is examined in the Phanerozoic Circum-Pacific Belt and in some Cryptozoic terranes. The Phanerozoic granitoids of the NW and NE Pacific Rims can be divided into reduced ilmenite series occurring in the accretionary terranes with compressional tectonic setting, and oxidised magnetite series intruding crystalline basements under extensional to intermediate regional stress regime. The ilmenite-series granitoids have negative but the magnetite series have positive δ34S values, which show a positive correlation with magnetic susceptibility of the granitoids. The negative δ34S sulphur originated in biogenic sulphur from accreted pelitic sediments and positive δ34S values show that sulphate sulphur migrated from seawater through subduction processes. The whole rock δ18O values are higher than 8 permil in the ilmenite series, but lower than 8 permil in the magnetite series, and as a whole show negative correlation with the magnetic susceptibility of the granitoids. The higher δ18O values reflect those of accreted sediments, whilst the lower δ18O values represent magmatic values of an oxidised mafic protolith at depth.

The predominance of ilmenite-series granitoids of the NW Pacific rim can be explained by well-developed accretionary terranes in which mafic magmas from depth mingled with felsic magmas from the accretionary complex to form granodioritic magmas, whilst that of magnetite-series granitoids is postulated to be oxidised igneous sources for the magma generation and an extensional and/or intermediate tectonic setting for the magma ascent. The absence of the accretionary wedges by tectonic erosion and/or no fore-arc sedimentation also helped to form magnetite-series granitoids. Potassic granitoids are generally of oxidised type. A-type granites in late orogenic environments also belong to the magnetite series. Adakitic high-Sr/Y granitoids are oxidised in the Mesozoic–Cenozoic but are reduced in the Archaean TTG, reflecting the redox state of the then-current sea-floor environment. The oldest magnetite-series granite so far known is the 3105 Ma-old biotite granite of the Nelspruit batholith, South Africa.
Experimental temperature–X(H2O)–viscosity relationship for leucogranites and comparison with synthetic silicic liquids
Authors: Whittington Alan , Richet Pascal , Behrens Harald , Holtz François , Scaillet Bruno
Published: July 2007

Viscosities of liquid albite (NaAlSi3O8) and a Himalayan leucogranite were measured near the glass transition at a pressure of one atmosphere for water contents of 0, 2·8 and 3·4 wt.%. Measured viscosities range from 1013·8 Pa. s at 935 K to 109·0 Pa. s at 1119 K for anhydrous granite, and from 1010·2 Pa. s at 760 K to 1012·9 Pa. s at 658 K for granite containing 3·4 wt.% H2O. The leucogranite is the first naturally occurring liquid composition to be investigated over the wide range of T-X(H2O) conditions which may be encountered in both plutonic and volcanic settings. At typical magmatic temperatures of 750°C, the viscosity of the leucogranite is 1011·0 Pa. s for the anhydrous liquid, dropping to 106·5 Pa. s for a water content of 3 wt.% H2O. For the same temperature, the viscosity of liquid NaAlSi3O8 is reduced from 1012·2 to 106·3 Pa. s by the addition of 1·9 wt.% H2O. Combined with published high-temperature viscosity data, these results confirm that water reduces the viscosity of NaAlSi3O8 liquids to a much greater degree than that of natural leucogranitic liquids. Furthermore, the viscosity of NaAlSi3O8 liquid becomes substantially nonArrhenian at water contents as low as 1 wt.% H2O, while that of the leucogranite appears to remain close to Arrhenian to at least 3 wt.% H2O, and viscosity–temperature relationships for hydrous leucogranites must be nearly Arrhenian over a wide range of temperature and viscosity. Therefore, the viscosity of hydrous NaAlSi3O8 liquid does not provide a good model for natural granitic or rhyolitic liquids, especially at lower temperatures and water contents.

Qualitatively, the differences can be explained in terms of configurational entropy theory because the addition of water should lead to higher entropies of mixing in simple model compositions than in complex natural compositions. This hypothesis also explains why the water reduces magma viscosity to a larger degree at low temperatures, and is consistent with published viscosity data for hydrous liquid compositions ranging from NaAlSi3O8 and synthetic haplogranites to natural samples. Therefore, predictive models of magma viscosity need to account for compositional variations in more detail than via simple approximations of the degree of polymerisation of the melt structure.
The influence of cordierite on melting and mineral-melt equilibria in ultra-high-temperature metamorphism
Authors: Harley Simon L. , Thompson P.
Published: July 2007

Experimentally constrained calibrations of the incorporation of H2 O and CO2 into cordierite as functions of P–T-aH2O-aCO2 are integrated with KFMASH grids which define mineral-melt equilibria in pelites. This is used to explore the impact of the volatile content and composition of cordierite on anatexis and melt-related processes in high-temperature (HT) and ultra-high-temperature (UHT) metamorphism. The strongly temperature-sensitive H2O content of cordierite coexisting with dehydration melts (0·4–1·6 wt.%) causes a 10–25% relative decrease in the amount of melt produced from pelites compared with models which treat cordierite as anhydrous.

KFMASH melting grids quantified for aH2O demonstrate consistency between the measured H2O contents in cordierite from granulite-migmatite terrains and mineral equilibria. These indicate anatexis with aH2O in the range 0·26–0·16 at 6–8 kbar and 870–930°C. The pressure-stability of cordierite+garnet with respect to orthopyroxene+sillimanite+quartz in KFMASH is strongly influenced by cordierite H2O content, which decreases from 1·1 to 0·5 wt.% along the melting reaction Grt+CrdH+Kfs=Opx+Sil+Qz+L. The lower-T invariant point involving biotite (8·8 kbar/900°C) that terminates this reaction has aH2O of 0·16±0·03, whereas the higher-T terminating invariant point involving osumilite (7·9 kbar/940°C) occurs at aH2O 0·08±0·02. Osumilite-bearing assemblages in UHT terrains imply aH2O of <0·08, and at 950–1000°C and 8–9 kbar calculated aH2O is only 0·04–0·02. Cordierites stable in osumilite-bearing assemblages or with sapphirine+quartz have maximum predicted H2O contents of ca. 0·2 wt.%, consistent with H2O measured in cordierites from two sapphirine-bearing UHT samples from the Napier Complex.

The addition of CO2to the H2O-undersaturated (dehydration-melting) system marginally decreases the temperature of melting because of the stabilisation of cordierite, the solid product of the peritectic melting reactions. The preferential incorporation of CO2 enhances the stability of cordierite, even at fixed aH2O, and causes the stability fields of Grt+Crd+Sil+Kfs+Qz+L and Grt+Opx+Crd+Kfs+Qz+L to expand to higher pressure, and to both higher and lower temperatures. The minimum solubility of H2O in granitic melt is independent of the CO2 content of cordierite, and the distribution of H2O between melt and cordierite is similar at a given melt H2O-content to the H2O-only system. This enhanced stability of CO2-bearing cordierite leads to a reduced stability range for osumilite-bearing assemblages to temperatures of ca. 950–975°C or greater. Cordierites in the Napier Complex UHT gneisses contain 0·5 and 1·05 wt.% CO2, consistent with a role for CO2 in stabilising cordierite with respect to osumilite in these unusual sapphirine-bearing granul
Low- and high-temperature granites
Authors: Chappell B. W. , White A. J. R. , Williams I. S. , Wyborn D.
Published: July 2007

I-type granites can be assigned to low- and high-temperature groups. The distinction between those groups is formally based on the presence or absence of inherited zircon in relatively mafic rocks of a suite containing less than about 68% SiO2, and shown in many cases by distinctive patterns of compositional variation. Granites of the low-temperature group formed at relatively low magmatic temperatures by the partial melting dominantly of the haplogranite components Qz, Ab and Or in H2O-bearing crustal source rocks. More mafic granites of this type have that character because they contain restite minerals, often including inherited zircon, which were entrained in a more felsic melt. In common with other elements, Zr contents correlate linearly with SiO2, except sometimes in very felsic rocks, and Zr generally decreases as the rocks become more felsic. All S-type granites are apparently low-temperature in origin. After most or all of the restite has been removed from the magma, these granites may evolve further by fractional crystallisation. High-temperature granites formed from a magma that was completely or largely molten, in which zircon crystals were not initially present because the melt was not saturated in that mineral. High-temperature suites commonly evolved compositionally through fractional crystallisation and they may extend to much more mafic compositions through the production of cumulate rocks. However, it is probable that, in some cases, the compositional differences within high-temperature suites arose from varying degrees of partial melting of similar source rocks. Volcanic equivalents of both groups exist and show analogous differences. There are petrographic differences between the two groups and significant mineralisation is much more likely to be associated with the high-temperature granites. The different features of the two groups relate to distinctive source rock compositions. Low-temperature granites were derived from source rocks in which the haplogranite components were present throughout partial melting, whereas the source materials of the high-temperature granites were deficient in one of those components, which therefore, became depleted during the melting, causing the temperatures of melting to rise.
Two subgroups of A-type granites in the coastal area of Zhejiang and Fujian Provinces, SE China: age and geochemical constraints on their petrogenesis
Authors: Qiu Jian-Sheng , Wang De-Zi , McInnes Brent I. A. , Jiang Shao-Yong , Wang Ru-Cheng , Kanisawa Satoshi
Published: July 2007

Late Cretaceous (90–100 Ma) A-type granites are widespread in the coastal area of the Zhejiang and Fujian Provinces, SE China. According to mineralogical and geochemical characteristics, the A-type granites in this belt can be further divided into aluminous and peralkaline subgroups. The aluminous subgroup often contains aluminous-rich minerals (e.g. spessartine and Mn-rich muscovite), while the peralkaline subgroup usually contains riebeckite, arfvedsonite and aegirine. Geochemically, the aluminous A-type granites show lower Nb, Zr, Ga, Y and REE abundances, and lower FeO*/MgO and Ga/Al than the peralkaline subgroup. When they occur in the same area, the two subgroups of A-type granites display quite similar initial Nd isotopic compositions, which are indicative of mixing of ancient basement crustal rocks with variable amounts of mantle materials. Integrated geological and geochemical investigations indicate that both the aluminous and the peralkaline magmas are highly evolved and reflect the residual liquids left after high degrees of fractional crystallisation in a deep magma chamber. The present authors suggest that the mineralogical and geochemical differences between the aluminous and peralkaline subgroups are likely to have been generated via different differentiation paths controlled by varying fluorine contents of the parent magmas.
Mafic rocks from the Ryoke Belt, southwest Japan: implications for Cretaceous Ryoke/San-yo granitic magma genesis
Authors: Nakajima Takashi , Kamiyama Hiroyuki , Williams Ian S. , Tani Kenichiro
Published: July 2007

Mafic rocks in the Ryoke belt, the Cretaceous granitic province in Southwest Japan, occur in two modes: (1) as mafic dykes and pillow-shaped enclaves, and (2) as isolated kilometresized bodies of gabbroic cumulate. The dykes and pillows have fine-grained textures with thin radiating plagioclase laths, indicative of quenching. The gabbroic cumulates are predominantly coarse-grained and commonly lithologically layered.

SHRIMP zircon U-Pb ages of both types of mafic rocks are in the range 71–86 Ma, late Cretaceous. The mafic rocks become younger eastwards, matching the along-arc age trend of the associated Cretaceous granites (Nakajima et al. 1990). Both types of mafic rocks were apparently generated during the same magmatic event that produced the Ryoke/San-yo granites. The mafic dykes and pillows are aphyric basaltic-andesites to andesites (SiO2 54–60 wt.%), with microphenocrysts of biotite and hornblende. They have a composition which is similar to mafic rocks from the northern Sierra Nevada, and also to medium-K calc-alkaline rocks from present-day arc volcanics. The gabbroic cumulates are mostly pyroxene-hornblende gabbros (SiO2 43–52 wt.%). Their bulk-rock chemical compositions are mostly unlike any magma compositions.

Both types of mafic rocks from the Ryoke belt have relatively high 87Sr/86Sr initial ratios (SrI), 0·7071–0·7097, which are similar to those of the associated granites. The granites were formed either by fractional crystallisation of the mafic magmas, or by partial melting of newly formed mafic rocks at depth. The high SrI indicates that the mafic magmas were derived from enriched mantle or mixed with enriched crustal materials. Even if the mixing occurred between primitive basaltic magma and metasedimentary rocks, then the basaltic andesite–andesite magmas must have contained more than 60% mantle-derived components. The Cretaceous magmatism in Southwest Japan represents a major episode of crustal growth by additions from the upper mantle in an arc setting.
Late Archaean Kenogamissi complex, Abitibi Subprovince, Ontario, Canada: doming, folding and deformation-assisted melt remobilisation during syntectonic batholith emplacement
Authors: Benn Keith
Published: July 2007

The Kenogamissi complex represents a large exposure of folded Late Archaean crystalline crust exposed within the Abitibi Subprovince, Ontario, Canada. It is composed of an heterogeneous amphibolite-grade orthogneiss unit, and several generations of batholiths and plutons of tonalite, granodiorite and granite composition. Together, the various units represent granitic magmatism during the period from 2740 Ma to 2660 Ma. Structural mapping and petrographic studies were focused on the orthogneiss unit (2723 Ma), on the newly defined Roblin tonalitegranodiorite batholith (ca. 2713 Ma) and on the highly strained metavolcanic rocks within the deformation aureole that surrounds the Kenogamissi complex. Structural analysis indicates that the Kenogamissi complex was emplaced into the greenstones as a dome that caused severe flattening and recumbent F2 refolding of earlier F1 folds in the deformation aureole. Doming is interpreted to be caused by the emplacement and inflation of tonalite-granodiorite batholiths, such as the Roblin Batholith, into the actively folding Swayze greenstone belt. Continued regional folding resulted in F3 refolding of F1 and F2 in the deformation aureole. Continued regional folding also deformed and folded the Kenogamissi complex and resulted in further uplift and emplacement of the complex into the greenstone belt. The early-formed magmatic foliation and compositional layering in the Roblin Batholith were folded by F3 while the batholith was still a crystal mush, and an F3 axial-surface magmatic foliation was locally formed. Folding of the partially molten Roblin Batholith also resulted in the remobilisation of fractionated liquids into shear zones which formed on the limbs of the F3 magmatic folds. Similar structures are present in the orthogneiss unit and are interpreted to represent remobilisation of melts which intruded the orthogneiss at the time of emplacement of the Roblin Batholith. The formation of the dykes on sheared fold limbs may be attributed to increased dilatancy during localised shearing of the crystal mush. Deformation-assisted remobilisation and extraction of fractionated liquids, and the possible transport of the fractionated liquids to higher levels in the crystallising Roblin Batholith, may have played a role in its magmatic differentiation.
Volcanic–plutonic links, plutons as magma chambers and crust–mantle interaction: a lithospheric scale view of magma systems
Authors: Metcalf Rodney V.
Published: July 2007

The northern Colorado River extensional corridor (NCREC, USA) provides an excellent record of coeval volcanic and mid- to upper-crustal (<13 km) plutonic suites. The NCREC is a 50–100-km-wide zone that records late Tertiary lithospheric extension, volcanism, continental sedimentation and plutonism. Compilation of published studies of NCREC magmatic rocks permits an assessment of volcanic–plutonic links, magma sources and magmatic processes. The volcanic sections provide an excellent record of magma compositions (basalt, trachyandesite, trachyte and rhyolite) which span a 9-million-year period in the Miocene age (20–11 Ma).

Contemporaneous Miocene plutons span a similar compositional range (gabbro, diorite, quartz monzonite and granite) and were emplaced during a 4·5-million-year interval from 17 to 12·5 Ma. Geochemical and isotopic compositions and compositional trends allow direct correlation between plutonic and volcanic suites across the entire compositional range. Petrogenetic models demonstrate that intermediate magmas formed by a combination of magma mixing and fractional crystallisation involving mantle-derived mafic with crustal-derived felsic end-member magmas. Plutons exhibit a variety of features which suggest magma chamber processes, including (1) mafic cumulate sequences, (2) felsic cumulate sequences, and (3) magma mingling and advanced stages of magma mixing. Thus, the NCREC plutonic-volcanic record provides a link between magmatic processes recorded in pluton magma chambers and magmatic products in the form of extrusive igneous rocks. The NCREC plutons represent upper crustal magma chambers which connected volcanic eruptive centres to deeper-level magma chambers, and ultimately, to zones of mantle and crustal mel
Fragmentation, nucleation and migration of crystals and bubbles in the Bishop Tuff rhyolitic magma
Authors: Gualda Guilherme A. R. , Cook David L. , Chopra Rahul , Qin Liping , Anderson Alfred T. , Rivers Mark
Published: July 2007

The Bishop Tuff (USA) is a large-volume, high-silica pyroclastic rhyolite. Five pumice clasts from three early stratigraphic units were studied. Size distributions were obtained using three approaches: (1) crushing, sieving and winnowing (reliable for crystals >100 μm); (2) microscopy of ∼1 mm3 fragments (preferable for crystals <100 μm); and (3) computerised X-ray microtomography of ∼1 cm3 pumice pieces.

Phenocryst fragments coated with glass are common, and the size distributions for all crystals are concave-upward, indicating that crystal fragmentation is an important magmatic process.

Three groups are recognised, characterised by: (1) high-density (0·759–0·902 g cm−3), high-crystal content (14·4–15·3 wt.%) and abundant large crystals (>800 μm); concave-downward size distributions for whole crystals indicate late-stage growth with limited nucleation, compatible with the slow cooling of a large, gas-saturated, stably stratified magma body; (2) low-density (0·499 g cm −3), low-crystal content (6·63 wt.%) and few large crystals; the approximately linear size distribution reveals that nucleation was locally important, perhaps close to the walls; and (3) intermediate characteristics in all respects.

The volumetric fraction of bubbles inversely correlates with the number of large crystals. This is incompatible with isobaric closed-system crystallisation, but can be explained by sinking of large crystals and rise of bubbles in the magma