bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Flavone Derivatives on Interleukin‐1β (IL‐1β) mRNA Expression and IL‐1β Protein Synthesis in Stimulated RAW 264.7 Macrophages
Authors: Blonska M. , Czuba Z. P. , Krol W.
Published: March 2003

It is known that the redox status of cells affects gene expression. Flavones, as natural antioxidants, efficiently modulate this status and may play a role in the regulation of inducible gene expression of inflammatory mediators. This study was designed to investigate the effect of five flavone derivatives variously substituted with hydroxyl groups (chrysin, galangin, kaempferol, quercetin and myricetin) on interleukin‐1β (IL‐1β) gene expression in stimulated RAW 264.7 macrophages. The cells were incubated with tested hydroxyflavones and stimulated with lipopolysaccharide (LPS) and interferon‐γ (IFN‐γ). Then, the following were estimated: the level of IL‐1β mRNA in these cells and the concentration of IL‐1β protein in cell‐culture supernatants and cell lysates.

Each of the tested compounds significantly decreased IL‐1β mRNA expression. The most potent inhibitor was chrysin (hydroxyflavone with two hydroxyl groups and a weak antioxidant activity). The effects of galangin and kaempferol were similar. Myricetin (hydroxyflavone with a strong antioxidant activity) significantly decreased the level of IL‐1β mRNA, but it had no effect on the IL‐1β protein synthesis.

The results indicated that hydroxyflavones could modulate the IL‐1β gene expression in activated RAW 264.7 macrophages via inhibiting gene transcription. This action seems unlikely to be the result of antioxidant properties of tested compounds.
Holocene stromatolites and microbial laminites associated with lenticular gypsum in a marine‐dominated environment, Ras El Shetan area, Gulf of Aqaba, Egypt
Authors: Aref Mahmoud A. M.
Published: March 2003

Field and petrographic investigations of Holocene evaporites in the Ras El Shetan area, Gulf of Aqaba, Egypt, indicate the presence of microbial mats either in the form of laminites or stromatolites. The morphology of microbial mats and gypsum crystal size characterize the following lithofacies: (1) slump‐stromatolitic gypsarenite, (2) random gypsrudite, (3) stromatolitic gypsarenite, and (4) microbially laminated gypsrudite. These evaporite lithofacies are formed above pre‐evaporitic mudstones rich in disrupted cyanobacterial filaments, burrows and cerithid gastropods. The morphology of the gypsum crystals is mainly lenticular, indicating enrichment of dissolved organic compounds in the depositional environment. The difference in size of the lenticular gypsum crystals is related to minor changes in salinity and temperature of the parent brine. Fluid inclusions in gypsum crystals indicate their formation at low temperature (<50°C) in a seawater sourced brine that evaporated to gypsum saturation or higher. The brine salinities range from 10·62 to 12·99 equivalent wt% NaCl, and the brine densities range from 1·08 to 1·11 g/cm3. The change in morphology of the microbial mats (stromatolites and laminites) is related mainly to changes in water depth, from a very shallow salina to a coastal sabkha. Lenticular gypsum nucleated displacively in the microbial mats from saline, oxygenated groundwater that seeped from the sea through a barrier.
Ichnofabrics and geometric configurations of	Ophiomorpha within a sequence stratigraphic framework: an example from the Upper Cretaceous US western interior
Authors: Anderson Brian G. , Droser Mary L.
Published: March 2003

Ichnofabric in the Upper Cretaceous Sego Sandstone and Anchor Mine Tongue of east‐central Utah can be differentiated into two components: (1) discrete Ophiomorpha and (2) mottling and other trace fossils. The ichnofabric index method was employed to evaluate spatial variability of the ichnofabrics within depositional sequences and component systems tracts. Indices were logged for amount of bioturbation caused solely by Ophiomorpha (Oii) and that represented by all other biogenic features (Bii). Values of Oii>  1 are more pervasive in lowstand systems tracts compared to transgressive systems tracts. This is consistent with the predominance of marginal and nearshore marine, sand‐dominated settings that are characteristic of lowstands, which are favourable habitats for colonization by Ophiomorpha producers. Ichnofabric index values vary both vertically and laterally within any given systems tract, reflecting differences in physical and biological parameters operating in the palaeoenvironment. These parameters include the total number and behaviours of organisms occupying the substrate, as well as substrate texture and grain size, and rates of sedimentation. The architectural style of Ophiomorpha was examined within five depositional facies: shelf, storm deposit, lower shoreface, shoreface, and estuarine. Inclinations of individual burrow elements were approximated relative to bedding planes, categorized as either vertical, inclined or horizontal, and then plotted on ternary diagrams. Based on the types of facies present, these results suggest that variations in the geometric configurations of Ophiomorpha are controlled primarily by physical energy levels, and the rate and nature of sedimentation. Results of this study have broad implications for understanding the physical factors affecting facies variability within sequences and systems tracts. When coupled with sedimentologic data, recognition of variations in the distribution of ichnofabrics and architectural style of Ophiomorpha can provide additional information useful for characterizing depositional environments, and therefore could be integrated with other basin analysis techniques to test and refine sequence stratigraphic interpretations.
Beach fetch distance and aeolian sediment transport
Authors: Jackson  , Cooper
Published: March 2003

An experiment was conducted to examine the influence of fetch distance on aeolian sediment transport on a natural sand beach at Benone Strand, County Londonderry, Northern Ireland. The site consisted of a wide dissipative beach, approximately 150 m wide at low tide and 80 m wide during high tide. Surface moisture levels (and hence dry fetch distance) were dictated by both local groundwater, from a stream outlet across the beach, as well as local tidal levels. An abundant dry sediment supply was available during the experiment. High‐resolution (1 Hz) measurements were made of wind speed and direction along with sediment flux. Wind velocity ranged from 2·1 to 8·1 m s–1 during the study. Second‐order polynomial sand transport equations were derived from the wind speed and trap results with r2 values of better than 0·93 for all data. When the data were sorted into velocity bins of 1 m s–1, there was no discernible relationship between fetch distance and sand transport, with a measured fetch distance range of 10–58 m available during the experiment. Results show that fetch distance is unimportant when an adequate sand supply is available. However, it is suggested that fetch may restrict the development of steady‐state transport under sediment‐limited conditions. Sediment availability is thus identified as a key variable in aeolian transport studies on natural beaches.
Fluvial responses to climate and sea‐level change: a review and look forward
Authors: Blum Michael D. , Törnqvist Torbjörn E.
Published: March 2003

Fluvial landforms and deposits provide one of the most readily studied Quaternary continental records, and alluvial strata represent an important component in most ancient continental interior and continental margin successions. Moreover, studies of the long‐term dynamics of fluvial systems and their responses to external or ‘allogenic' controls, can play important roles in research concerning both global change and sequence‐stratigraphy, as well as in studies of the dynamic interactions between tectonic activity and surface processes. These themes were energized in the final decades of the twentieth century, and may become increasingly important in the first decades of this millennium.

This review paper provides a historical perspective on the development of ideas in the fields of geomorphology/Quaternary geology vs. sedimentary geology, and then summarizes key processes that operate to produce alluvial stratigraphic records over time‐scales of 103−106 years. Of particular interest are changes in discharge regimes, sediment supply and sediment storage en route from source terrains to sedimentary basins, as well as changes in sea‐level and the concept of accommodation. Late Quaternary stratigraphic records from the Loire (France), Mississippi (USA), Colorado (Texas, USA) and Rhine–Meuse (The Netherlands) Rivers are used to illustrate the influences of climate change on continental interior rivers, as well as the influence of interacting climate and sea‐level change on continental margin systems.

The paper concludes with a look forward to a bright future for studies of fluvial response to climate and sea‐level change. At present, empirical field‐based research on fluvial response to climate and sea‐level change lags behind: (a) the global change community's understanding of the magnitude and frequency of climate and sea‐level change; (b) the sequence‐stratigraphic community's desire to interpret climate and, especially, sea‐level change as forcing mechanisms; and (c) the modelling community's ability to generate numerical and physical models of surface processes and their stratigraphic results. A major challenge for the future is to catch up, which will require the development of more detailed and sophisticated Quaternary stratigraphic, sedimentological and geochronological frameworks in a variety of continental interior and continental margin settings. There is a particular need for studies that seek to document fluvial responses to allogenic forcing over both shorter (102−103 years) and longer (104−106 years) time‐scales than has commonly been the case to date, as well as in larger river systems, from source to sink. Studies of Quaternary systems in depositional basin settings are especially critical because they can provide realistic analogues for interpretation of the pre‐Quaternary rock record.
A steep‐fronted Carboniferous carbonate platform: clinoformal geometry and lithofacies (Picos de Europa, NW Spain)
Authors: Bahamonde Juan R. , Vera Carmen , Colmenero Juan R.
Published: March 2003

A steep‐margined carbonate platform is developed in the Carboniferous synorogenic foreland basin of northern Spain. Dips of 60–90° produced during Late Carboniferous thrusting enable cross‐sections of a 4‐km‐wide portion of the marginal area of this platform (Las Llacerias outcrop) to be studied in aerial photographs at a seismic scale. Three stratal domains are observed: (1) a horizontal‐bedded platform; (2) a clinoformal‐bedded margin with a relief of up to 500 m; and (3) a low‐angle toe‐of‐slope, where slope beds interfinger with basin sediments. The slope shows well‐bedded sigmoidal clinoforms with depositional dips ranging from 15° to 32°. Based on lithology and stratal patterns, four facies groups have been recognized: (1) a flat‐topped platform, in which thick algal boundstone, skeletal packstone–grainstone and peloidal micrite wackestone with a poorly rhythmic character prevail; (2) the platform margin and upper slope, characterized by microbial boundstone spanning a bathymetric range of ≈150 m measured from the break of slope; (3) a slope, predominantly composed of margin‐derived rudstones and breccias; and (4) a toe‐of‐slope to basin zone, where a cyclic alternation of spiculitic siltstones, packstone to grainstone calciturbidites and rudstone/breccia is visible. Five successive stages of platform development are deduced: (1) Bashkirian: flooding of the pre‐existing Serpukhovian platform giving rise to the nucleation of a low‐angle ramp to the south‐east of the study area with microbial mud‐mound accumulations, and breccias and calciturbidites on the margins; (2) Early Moscovian: an influx of siliciclastic sediment buried part of the platform and reduced the area of carbonate sedimentation; (3) Moscovian: aggradation and progradation of the carbonate system produced an extensive steep‐margined and flat‐topped shallow‐water platform (shelf system); (4) Latest Moscovian–earliest Kasimovian: drowning of the platform; and (5) Kasimovian: covering of the platform by marly calcareous ramp sediments.
Dolomitization by penesaline sea water in Early Jurassic peritidal platform carbonates, Gibraltar, western Mediterranean
Authors: Qing Hairuo , Bosence Daniel W. J. , Rose Edward P. F.
Published: March 2003

Peritidal carbonates of the Lower Jurassic (Liassic) Gibraltar Limestone Formation, which form the main mass of the Rock of Gibraltar, are replaced by fine and medium crystalline dolomites. Replacement occurs as massive bedded or laminated dolomites in the lower 100 m of an ≈460‐m‐thick platform succession. The fine crystalline dolomite has δ18Ο values either similar to, or slightly higher than, those expected from Early Jurassic marine dolomite, and δ13C values together with 87Sr/86Sr ratios that overlap with sea‐water values for that time, indicating that the dolomitizing fluid was Early Jurassic sea water. Absence of massive evaporitic minerals and/or evaporite solution‐collapse breccias in these carbonate rocks indicates that the salinity of sea water during dolomitization was below that of gypsum precipitation. The occurrence of peritidal facies, a restricted microbiota and rare gypsum pseudomorphs are also consistent with penesaline conditions (salinity 72–199‰). The medium crystalline dolomite has some δ18Ο and δ13C values and 87Sr/86Sr ratios similar to those of Early Jurassic marine dolomites, which indicates that ambient sea water was again a likely dolomitizing fluid. However, the spread of δ18Ο, δ13C and 87Sr/86Sr values indicates that dolomitization occurred at slightly increased temperatures as a result of shallow (≈500 m) burial or that dolomitization was multistage. These data support the hypothesis that penesaline sea water can produce massive dolomitization in thick peritidal carbonates in the absence of evaporite precipitation. Taking earlier models into consideration, it appears that replacement dolomites can be produced by sea water or modified sea water with a wide range of salinities (normal, penesaline to hypersaline), provided that there is a driving mechanism for fluid migration. The Gibraltar dolomites confirm other reports of significant Early Jurassic dolomitization in the western Tethys carbonate platforms.
Isotopic constraints on the genesis and age of autochthonous glaucony in the Oligo‐Miocene Torquay Group, south‐eastern Australia
Authors: Kelly Jonathan C. , Webb John A. , Maas Roland
Published: March 2003

The Oligo‐Miocene Torquay Group at Bird Rock in south‐eastern Australia comprises a sequence of fine‐grained skeletal carbonates and argillaceous and glauconitic sandstones, deposited in a cool‐water, mid‐shelf environment. The Bird Rock glaucony is autochthonous and consists predominantly of randomly interstratified glauconitic smectite, which constitutes bioclast infills and faecal pellet replacements. The results of Rb–Sr and oxygen isotopic analysis of samples taken from a single glauconitic horizon (the BW horizon) indicate that the glaucony developed through a series of simultaneous dissolution–crystallization reactions, which occurred during very early diagenesis in a closed or isochemical system, isolated from the ambient marine environment. The constituent ions of the glaucony were derived primarily from terrigenous clay minerals, but considerable potassium may have been sourced indirectly from sea water, through potassium enrichment of clay precursors. The pore fluids associated with glauconitization were marine derived, but progressively modified by the dissolution–crystallization of detrital clay minerals and autochthonous glaucony. Rb–Sr data for the BW horizon indicate that dating glauconies may be somewhat problematic, as co‐genetic glauconitic minerals can show a range of initial strontium compositions, which reflect the incorporation of strontium derived from mineralogical precursors and/or contemporaneous sea water. Rb–Sr isochrons indicate that the glaucony of the BW horizon formed at 23 ± 3 Ma. This age is in good agreement with both the established biostratigraphy and a 87Sr/86Sr age for the horizon (23 ± 1 Ma), but could only be determined using the independent age constraint and the estimate of the 87Sr/86Sr ratio of contemporaneous sea water provided by analysis of associated biogenic carbonate.
Dolomitization of the Capitan Formation forereef facies (Permian, west Texas and New Mexico): seepage reflux revisited
Authors: Melim Leslie A. , Scholle Peter A.
Published: March 2003

AbstractInterpretation of seepage reflux dolomitization is commonly restricted to intervals containing evaporites even though several workers have modelled reflux of mesosaline brines. This study looked at the partially dolomitized forereef facies of the Capitan Formation to test the extent of reflux dolomitization and evaluate the possible role of the near‐backreef mesosaline carbonate lagoon as an alternative source of dolomitizing fluids. The Capitan Formation forereef facies ranges from 10% to 90% dolomite. Most of the dolomite is fabric preserving and formed during early burial after marine cementation, before and/or during evaporite cementation and before stylolitization. Within the forereef facies, dolomite follows depositional units, with debris‐flow and grain‐flow deposits the most dolomitized and turbidity‐current deposits the least. The amount of dolomite increases with stratigraphic age and decreases downslope. Within the reef facies, dolomite is restricted to haloes around fractures and primary cavities except where the reef facies lacks marine cements and, in contrast, is completely dolomitized. This dolomite distribution supports dolomitization by sinking fluids. Oxygen isotopic values for fabric‐preserving dolomite (δ18O = 0·9 ± 1·0‰,N = 101) support dolomitization by sea water to isotopically enriched sea water. These values are closer to the near‐backreef dolomite (δ18O = 2·1 ± 0·7‰,N = 48) than the hypersaline backreef dolomite (δ18O = 3·6 ± 0·9‰,N = 11). Therefore, the fabric‐preserving dolomite is consistent with dolomitization during seepage reflux of mainly mesosaline brines derived from the near‐backreef carbonate lagoon. The occurrence of mesosaline brine reflux in the Capitan Formation has important implications for dolomitization in forereef facies and elsewhere. First, any area with a restricted carbonate lagoon may be dolomitized by refluxing brines even if there are no evaporite facies present. Secondly, such brines may travel significant distances vertically provided permeable pathways (such as fractures) are present. Therefore, the absence of immediately overlying evaporite or restricted facies is not sufficient cause to eliminate reflux dolomitization from consideration.
Cyclostratigraphy and high‐frequency carbon isotope fluctuations in Upper Cretaceous shallow‐water carbonates, southern Italy
Authors: Buonocunto Francesco P. , Sprovieri Mario , Bellanca Adriana , D'Argenio Bruno , Ferreri Vittoria , Neri Rodolfo , Ferruzza Gaetano
Published: March 2003

Abstract A detailed carbon isotope study has been carried out on a Santonian (Upper Cretaceous) carbonate platform succession that crops out at Monte Sant'Erasmo (southern Italy). Previous centimetre‐scale studies on this succession have shown that high‐frequency eustatic changes, resulting from the Earth's orbital fluctuations, controlled the hierarchical organization of the depositional and early diagenetic features in elementary cycles, bundles (groups of three to five elementary cycles) and superbundles (groups of three or four bundles). The elementary cycles, which correspond to single beds, suggest a control caused by Earth's precession; the bundles and superbundles record the short (≈ 100 kyr) and long (≈ 400 kyr) eccentricity periodicity respectively. The δ13C signal of the Monte Sant'Erasmo succession is cyclic in nature and may be considered to be a reliable proxy for the sedimentary evolution (and related sea‐level history) of the analysed sequence. The carbon isotope cyclicity is recorded at bundle and superbundle level, but it is not evident at the scale of the elementary cycles, at least with the sampling interval used in this study. Spectral analysis of the δ13C record shows two main peaks corresponding to the short‐ and long‐eccentricity periodicity, whereas the precession signal is not evident in the power spectrum. In addition, lithofacies analysis shows that, in each bundle (and superbundle), higher C isotope values occur in sediments characterized by marine cements, whereas lower values are normally found in more restricted deposits overprinted by early meteoric diagenesis. Early diagenesis, driven by periodic sea‐level fluctuations, developed in either shallow‐subtidal (marine diagenesis) or subaerial‐exposed (meteoric overprint) sedimentary environments and directly influenced the carbon isotope signature. As a consequence, the δ13C record at Monte Sant'Erasmo reflects high‐frequency climatic oscillations controlling both environmental and early diagenetic changes. The long‐term isotopic record is similar to that of contemporaneous pelagic sections in England and elsewhere in Italy. It is concluded that the δ13C signature of shallow‐water carbonates, such as those of Monte Sant'Erasmo, offers great potential for correlation with coeval sections, including those of the pelagic realm.
The Middle–Late Jurassic forced regression and disconformity in central Portugal: eustatic, tectonic and climatic effects on a carbonate ramp system
Authors: Azerêdo Ana C. , Wright V. Paul , Ramalho Miguel M.
Published: March 2003

Abstract Successions across the Middle–Upper Jurassic disconformity in the Lusitanian Basin (west‐central Portugal) are highly varied, and were probably developed on a large westward‐inclined hangingwall of a half‐graben. The disconformity is preceded by a complex forced regression showing marked variations down the ramp, and provides an example of the effects of rapid, relative sea‐level falls on carbonate ramp systems. In the east, Middle Jurassic inner ramp carbonates (‘Candeeiros’ facies) are capped by a palaeokarstic surface veneered by ferruginous clays or thick calcretes. In the west, mid‐outer ramp marls and limestones (‘Brenha’ facies) are terminated by two contrasting successions: (1) a sharp‐based carbonate sandbody capped by a minor erosion surface, overlain by interbedded marine–lagoonal–deltaic deposits with further minor erosion/exposure surfaces; (2) a brachiopod‐rich limestone with a minor irregular surface, overlain by marls, lignitic marls with marine and reworked non‐marine fossils and charophytic limestones, with further minor irregular surfaces and capped by a higher relief ferruginous erosional surface. The age ranges from Late Bathonian in the east to Late Callovian in the west. This disconformity assemblage is succeeded by widespread lacustrine–lagoonal limestones with microbial laminites and evaporites (‘Cabaços’ facies), attributed to the Middle Oxfordian. Over the whole basin, increasingly marine facies were deposited afterwards. In Middle Jurassic inner‐ramp zones in the east, the overall regression is marked by a major exposure surface overlain by continental sediments. In Middle Jurassic outer‐ramp zones to the west, the regression is represented initially by open‐marine successions followed by either a sharp marine erosion surface overlain by a complex sandbody or minor discontinuities and marginal‐marine deposits, in both cases capped by the major lowstand surface. Reflooding led to a complex pattern of depositional conditions throughout the basin, from freshwater and brackish lagoonal to marginal‐ and shallow‐marine settings. Additional complications were produced by possible tilting of the hangingwall of the half‐graben, the input of siliciclastics from westerly sources and climate change from humid to more seasonally semi‐arid conditions. The Middle–Late Jurassic sea‐level fall in the Lusitanian Basin is also recorded elsewhere within the Iberian and other peri‐Atlantic regions and matches a transgressive to regressive change in eustatic sea‐level curves, indicating that it is related in part to a global event.
Systematic revision of Nearctic species of Achalcus Loew (Diptera: Dolichopodidae) with comments on their phylogeny, ecology and zoogeography
Authors: POLLET MARC , CUMMING JEFFREY M.
Published: March 2003

The species of the genus Achalcus Loew from the Nearctic Region are revised and a key to males and females is provided. Achalcus utahensis (Harmston & Miller) and A. oregonensis (Harmston & Miller) are redescribed, and A. californicus sp.n., A. dytei sp.n. and A. similis sp.n. are described. Together with eight of the nine known Palaearctic species of the genus, they represent a monophyletic species group, which is characterized by the presence of five pairs of dorsocentral bristles and the incorporation of the epandrial setae onto the shaft of the epandrial lobe. Like their Palaearctic congeners, most Nearctic species occur in damp habitats, such as coastal forests and riparian vegetation. Most specimens were collected in the Pacific coastal states from British Columbia to California, but one species occurs in Utah, and one of six species which were not described because males are lacking, was discovered in Ontario.
Phylogenetic analysis of Myxophaga (Coleoptera) using larval characters
Authors: Beutel R. G.. , Maddison D. R.. , Haas A..
Published: March 2003

A phylogenetic parsimony analysis of fifty‐four larval characters of Myxophaga (excluding Lepiceridae) resulted in two minimal length cladograms. The monophyly of Torridincolidae, Hydroscaphidae and Microsporidae is supported by several autapomorphies: miniaturization, flattened body with laterally extended tergites, broadened head, scale‐like surface structures, broad tentorial bridge, disc‐shaped labral sensilla, spiracular gills and pupation in the last larval exuviae. Hydroscaphidae are the sister group of Microsporidae. Larvae of both families are characterized by semi‐entognathous mouthparts, tergites with posterior rows of lancet‐shaped setae, claws with flattened basal spines and balloon‐shaped spiracular gills. The monophyly of all families is supported by autapomorphies. Torridincolidae excludingDeleveais defined as a monophylum by four derived character states: body ovoid, thorax semicircular and as long as abdomen, labral sensilla fused and abdominal sternite IX distinctly reduced and triangular. The monophyly of Torridincolinae (sensuEndrödy‐Younga 1997b) is supported by two autapomorphies. The proposed branching pattern suggests that the early representatives of Myxophaga (excluding Lepiceridae) were living in aquatic conditions with a preference for hygropetric habitats. The tendency to live on rocks in running water and miniaturization have played an important role in myxophagan evolution.
Cladistic analysis of Neuroptera and their systematic position within Neuropterida (Insecta: Holometabola: Neuropterida: Neuroptera)
Authors: Aspöck Ulrike , Plant John D. , Nemeschkal Hans L.
Published: March 2003

A phylogenetic analysis of Neuroptera using thirty‐six predominantly morphological characters of adults and larvae is presented. This is the first computerized cladistic analysis at the ordinal level. It included nineteen species representing seventeen families of Neuroptera, three species representing two families (Sialidae and both subfamilies of Corydalidae) of Megaloptera, two species representing two families of Raphidioptera and as prime outgroup one species of a family of Coleoptera. Ten equally most parsimonious cladograms were found, of which one is selected and presented in detail. The results are discussed in light of recent results from mental phylogenetic cladograms. The suborders Nevrorthi‐ formia, Myrmeleontiformia and Hemerobiiformia received strong support, however Nevrorthiformia formed the adelphotaxon of Myrmeleontiformia + Hemerobiiformia (former sister group of Myrmeleontiformia only). In Myrmeleontiformia, the sister‐group relationships between Psychopsidae + Nemopteridae and Nymphidae + (Myrmeleontidae + Ascalaphidae) are corroborated. In Hemerobiiformia, Ithonidae + Polystoechotidae is confirmed as the sister group of the remaining families. Dilaridae + (Mantispidae + (Rhachiberothidae + Berothidae)), which has already been proposed, is confirmed. Chrysopidae + Osmylidae emerged as the sister group of a clade comprising Hemerobiidae + ((Coniopterygidae + Sisyridae) + (dilarid clade)). Despite the sister‐group relationship of Coniopterygidae + Sisyridae being only weakly supported, the position of Coniopterygidae within the higher Hemerobiiformia is corroborated. At the ordinal level, the analysis provided clear support for the hypothesis that Megaloptera + Neuroptera are sister groups, which upsets the conventional Megaloptera + Raphidioptera hypothesis.
Phylogenetic revision of Agapophytinae subf.n. (Diptera: Therevidae) based on molecular and morphological evidence
Authors: Winterton Shaun L. , Yang Longlong , Wiegmann Brian M. , Yeates David K.
Published: March 2003

Agapophytinae subf.n. is a highly diverse lineage of Australasian Therevidae, comprising eight described and two new genera:AgapophytusGuérin‐Méneville,AcupalpaKröber,AcraspisaKröber,BelonalysKröber,BonjeaniaIrwin & Lyneborg,ParapsilocephalaKröber,AcatopygiaKröber,LaxotelaWinterton & Irwin,Pipinniponsgen.n. andPatanothrixgen.n. A genus‐level cladistic analysis of the subfamily was undertaken using sixty‐eight adult morphological characters andc.1000 base pairs of the elongation factor‐1α (EF‐1α) protein coding gene. The morphological data partition produced three most parsimonious cladograms, whereas the molecular data partition gave a single most parsimonious cladogram, which did not match any of the cladograms found in the morphological analysis. The level of congruence between the data partitions was determined using the partition homogeneity test (HTF) and Wilcoxon signed ranks test. Despite being significantly incongruent in at least one of the incongruence tests, the partitions were combined in a simultaneous analysis. The combined data yielded a single cladogram that was better supported than that of the individual partitions analysed separately. The relative contributions of the data partitions to support for individual nodes on the combined cladogram were investigated using Partitioned Bremer Support. The level of support for many nodes on the combined cladogram was non‐additive and often greater than the sum of support for the respective nodes on individual partitions. This synergistic interaction between incongruent data partitions indicates a common phylogenetic signal in both partitions. It also suggests that criteria for partition combination based solely on incongruence may be misleading. The phylogenetic relationships of the genera are discussed using the combined data. A key to genera of Agapophytinae is presented, with genera diagnosed and figured. Two new genera are described:Patanothrixwith a new species (Pat. skevingtoni) andPat. wilsoni(Mann) transferred fromParapsilocephala, andPipinniponswith a new species (Pip. kroeberi).Pipinnipons fascipennis(Kröber) is transferred fromSquamopygiaKröber andPip. imitans(Mann) is transferred fromAgapophytus.Agapophytus bicolor(Kröber) is transferred fromParapsilocephala.Agapophytus varipennisMann is synonymised withAga. queenslandiKröber andAga. flavicornisMann is synonymised withAga. pallidicornis(Kröber).
Assessing the nature of tectonic contacts using fission‐track thermochronology: an example from the Calabrian Arc, southern Italy
Authors: Thomson
Published: March 2003

Fission‐track thermochronology applied to the nappe pile of the Calabrian Arc of southern Italy, particularly within the continental basement rocks, has provided important new constraints on the nature of some of the tectonic contacts. In southern Calabria an important phase of lower Miocene crustal extension is indicated. In northern Calabria no Oligocene or younger extension is seen. Here, the emplacement of continental basement rocks with Alpine metamorphism over ophiolitic rocks with little or no metamorphism is constrained as a thrust of lower to middle Miocene age related to collision of the Calabrian Arc with the Adria plate margin. It is proposed that reduction in the plate convergence velocity during collision of a retreating subduction zone with a continental margin is, at least partly, an explanation for the onset of extension in southern Calabria during the Miocene.
Unconformity of red sandstones in north Vietnam: field evidence for Indosinian orogeny in northern Indochina?
Authors: Lacassin  , Leloup  , Trinh  , Tapponnier
Published: March 2003

We re‐examine several unconformity sites in northwestern Vietnam where the Indosinian orogenesis has been defined. Field observations in the Black‐River (Song Da) region, near Son La, demonstrate that red sandtones and conglomerates, reportedly of Cretaceous age, occur unconformably above schistosed epimetamorphic middle‐Triassic sediments. A mesozoic unconformity thus really exists in this region, though the age of deformation is poorly contrained (upper Triassic to upper Cretaceous). In most places, however, the unconformity is strongly deformed, folded Triassic limestones are often thrusted onto the Cretaceous rocks. This implies that Tertiary deformations probably due to the India–Asia collision have been strong in the northern part of the Indochina block.
Contrasting palaeosol development in two different tectonic settings: the Upper Buntsandstein of the Western Iberian Ranges, Central Spain
Authors: Alonso‐Zarza  , Sopeña  , Sánchez‐Moya
Published: March 2003

Palaeosols may offer excellent evidence for the development of sedimentary basins but few studies have used diagenetically altered material: here we show that material of this sort can also reflect the sedimentary environment. The Lower to Middle Triassic red beds of the western Iberian Ranges were deposited in a tectonically active half‐graben in which subsidence rates varied along the basin as a response to differential fault movements. During this period the basin was filled by a set of fluvial units with interbedded palaeosols. The palaeosols show typical pedogenic calcrete profiles, although extensive dolomitization has deleted part of their microstructure; however, macrostructure and morphology are preserved. Differences in the maturity stages of the palaeosols are related to the changes in subsidence and sedimentation rates along the basin. Thus, two different scenarios are recognized at: (i) the hanging wall, Riba de Santiuste area, where palaeosols reach stage III as the episodic tilting of the floodplain inhibited the development of more mature soils and (ii) the footwall, Cercadillo area, where palaeosols attain stage V maturity, favoured by prolonged periods of tectonic stability resulting in lower sedimentation rates over the floodplain areas.
The discovery of scapolite marbles in the Biscay Synclinorium (Basque–Cantabrian basin, Western Pyrenees): geodynamic implications
Authors: Cuevas J. , Tubía J.M.
Published: March 2003

We report the presence of scapolite marbles in the Biscay Synclinorium of the Basque–Cantabrian basin, the link between the mainland Pyrenees and the North Iberian palaeomargin. From their microstructures and mineral assemblages these marbles are correlated with similar marbles formed during the Cretaceous metamorphism representative of the North Pyrenean Zone. Their setting in an area with northward‐verging structures leads us to propose a new location of the North Pyrenean Fault through the Basque–Cantabrian basin. Available geophysical information, gravity and magnetic anomalies, is better explained with this new proposal, which elucidates a major outstanding matter of Pyrenean geology.
The influence of the South‐west Indian monsoon on continental deposition over the past 130 kyr, Gujarat, western India
Authors: Khadkikar A.S. , Mathew G. , Malik J.N. , Gundu Rao T.K. , Chowgaonkar M.P. , Merh S.S.
Published: March 2003

Ocean and ice core records of the intensity of the South‐west Indian Monsoon (SwIM) show rapid shifts in most proxy indicators of climate over the past 125 kyr on decadal to millenial scales. However, the responses of continental environments to such perturbations remain unknown due to the absence of a suitable long‐term continental record. The stratigraphic record from Gujarat, western India, an area where all sedimentological processes are governed by the vagaries of the SwIM, reveals three aggradation phases that represent deposits of seasonal rivers (AP1), ephemeral rivers (AP2) and dust storms (AP3). Based on a review of available dates and new ESR dates on the oldest exposed calcretes from palaeovertisols these phases are assigned the time brackets 135–100 kyrbp(AP1), 100–20 kyrbp(AP2) and 20–6 kyrbp(AP3). These results suggest that continental depositional environments respond in a subdued manner and are separated by thresholds. For climate shifts to effect durable changes in the continental depositional environment, a period between > 5 kyr and 16 kyr is the minimum time required to permanently change the landscape of an area. Alternatively, catastrophic changes in terrestrial depositional environments may also be effected by abrupt climatic shifts that are beyond the tolerance limits of the depositional systems.
Beloc, Haiti, revisited: multiple events across the KT boundary in the Caribbean
Authors: Stinnesbeck W. , Keller G. , Adatte T. , Stüben D. , Kramar U. , Berner Z. , Desremeaux C. , Molière E.
Published: March 2003

Examination of new expanded K/T boundary sections near Beloc, Haiti, reveals deposition of a glass spherule‐rich deposit (SRD) and two (PGE) anomalies (one Ir‐dominated and one Pd‐dominated) during the early Danian Parvularugoglobigerina eugubina Zone [Pla(l)]. The presence of the Haiti SRD within the early Danian is interpreted as being due to reworking. Ir is only slightly elevated within the SRD but forms an anomaly at the top of the SRD extending into the overlying pelagic limestones. It is unclear at present whether this Ir anomaly results from mechanical reworking of an impact at the K/T boundary, or an additional impact event in the early Danian. The second PGE anomaly upsection is dominated by Pd and Pt and is more compatible with a magmatic origin. This suggests a multi‐event scenario consistent with one (and possibly two) impact(s), followed by a PGE‐enriched volcanic event in the Caribbean.
Early Himalayan exhumation: Isotopic constraints from the Indian foreland basin
Authors: Najman  , Bickle  , Chapman
Published: March 2003

Nd‐ and Sr‐isotopic compositions of Palaeogene foreland basin sediments are used to provide insights into early Himalayan evolution, particularly the timing of exposure of high87Sr/86Sr units, erosion of which may have caused the late Tertiary increase in oceanic Sr‐isotopic ratios. During the late Palaeocene–early Eocene, erosion was from mixed sources including suture zone rocks. Exhumation of the High Himalaya was occurring by the time of deposition of alluvial sediments after mid‐Oligocene times and this source has dominated Himalayan sediments from at least this time until the present day. The transition is interpreted to reflect exhumation of ‘basement rocks’ of the Indian plate, when the High Himalaya became a sufficient topographic barrier to separate suture zone rocks from the foreland basin. The marked rise in seawater87Sr/86Sr from 40 Ma is consistent with the erosion of a Himalayan source with a high87Sr/86Sr ratio.
Can rainfall trigger volcanic eruptions? A mechanical stress model of an active volcano: ‘Piton de la Fournaise’, Reunion Island
Authors: Violette S. , De Marsily G. , Carbonnel J. P. , Goblet P. , Ledoux E. , Tijani S. M. , Vouille G.
Published: March 2003

This paper relates the hydrology of a volcano to its eruptive activity, which seem to be correlated. Based on the groundwater pattern previously determined by hydrologic and thermal modelling, we formulate hypotheses for the mechanisms linking rainfall and volcanic eruptions. We focus on: mechanical loading by the weight of the infiltrated rain, which might favour magma overpressure or slope instability on the eastern volcanic flank; unloading of the infiltrated water, discharged toward the ocean, which could increase the tangential tensile stress above the magma chamber. We test the sensitivity of the model to the magma chamber geometry and the rainfall distribution. The mechanical unloading of the infiltrated water is the mechanism most likely to trigger eruptions. However, the presence of a sliding surface and rainfall loading could favour the development of tensile stress in the ‘shell’ surrounding the magma chamber but with a lower intensity than in the previous case.
Slab break‐off – abrupt cut or gradual detachment? New insights from the Vrancea Region (SE Carpathians, Romania)
Authors: Sperner B. , Lorenz F. , Bonjer K. , Hettel S. , Müller B. , Wenzel F.
Published: March 2003

Slab break‐off is a plate‐tectonic process which does not only return lithospheric material into the deeper mantle, but also has severe effects on surface movements and seismic hazard: slab‐pull induced seismicity is reduced when the subducted slab decouples from the overlying crust. In the Vrancea region (SE Carpathians), strong earthquakes frequently occur at intermediate depths (70–180 km) in a laterally small volume, while the crust shows low but distributed seismicity. The stress pattern shows similar partitioning with vertical extension in the slab and no preferred orientation in the overlying crust. Both features indicate a decoupling between slab and overlying crust, either by slab break‐off or delamination. However, the strong vertical elongation of the slab requires that the upper end of the slab is fixed vertically. Thus, a ‘soft’ coupling is assumed that is strong enough to enable elongation of the slab, but weak enough to inhibit ‘quasi‐static’ stress transfer to the overlying crust.
A 400‐km‐long piggyback basin (Upper Aptian–Lower Cenomanian) in the Eastern Alps
Authors: Wagreich Michael
Published: March 2003

The Late Aptian to Early Cenomanian Tannheim–Losenstein basin constitutes an early, deep‐marine piggyback trough which formed on the Cretaceous orogenic wedge of the Eastern Alps. The narrow basin extended over more than 400 km from the western part of the Northern Calcareous Alps into the Western Carpathians (Slovakia), as suggested by similarities in stratigraphy – e.g. the common coarsening upward succession of marls, sandstones, and conglomerates – and by similarities in timing of deformation and the uniform composition, e.g. similar heavy mineral assemblages. The coarsening‐upward succession resulted from the progradation of a coarse‐grained slope apron into a hemipelagic basin. The composition of detrital material constitutes evidence for a uniform source area to the north, along the entire length of the basin, comprising continental basement, Mesozoic sediments and remnants of ophiolites. The basin formation marked the onset of compression along the northern Austroalpine plate boundary.
Recycling of continental crust into the mantle as revealed by Kytlym dunite zircons, Ural Mts, Russia
Authors: Bea F. , Fershtater G. B. , Montero P. , Whitehouse M. , Levin V. Ya. , Scarrow J. H. , Austrheim H. , Pushkariev E. V.
Published: March 2003

The presence of zircons of crustal origin in the dunites of Kytlym, a subduction‐related concentrically zoned dunite–clinopyroxenite–gabbro massif of the Urals Platinum‐Bearing Belt, may provide the first direct evidence of the recycling of continental crust into the mantle. Zircons were part of subducted sediments that melted to produce silicic magmas with entrained restitic zircons. These melts induced partial melting in the overlying mantle, which later crystallized as the Kytlym massif. Zircons rapidly captured into early formed dunites were prevented from dissolving completely and underwent different degrees of recrystallization. A few crystals still record their original ages, which range from ∼410 Myr to ∼2800 Myr, thus revealing a different origin. The majority, however, recrystallized in the presence of a limited amount of melt and record the diapir formation, 350–370 Ma, which was coeval with the Uralian high‐pressure metamorphism. Lastly, several grains record an age of ∼330 Myr, which is identical, within error, to the Rb–Sr age of the tilaitic gabbros, (337 ± 22 Myr), and may, therefore, represent the crystallization age of the last melts formed during the evolution of Kytlym.
Cretaceous–Tertiary Rhenodanubian flysch wedge (Eastern Alps): clues to sediment supply and basin configuration from zircon fission‐track data
Authors: Trautwein Britta , Dunkl István , Kuhlemann Joachim , Frisch Wolfgang
Published: March 2003

The provenance of Cenomanian to Eocene flysch deposits accreted along the northern margin of the Eastern Alps has been investigated by means of zircon fission‐track (FT) geochronology and zircon morphology. The Rhenodanubian flysch and Ybbsitz klippen zone comprise several nappes representing the Main flysch and Laab basins. The Laab basin received sediments of stable European provenance, indicated by pre‐Variscan, Variscan, and Permian–Triassic zircon FT ages, and was thus located in the immediate south of the European margin. The Main flysch basin was supplied mainly from the evolving Eastern Alps and was therefore situated south of the Laab basin. Zircon populations with Permian to Jurassic cooling ages in the Main flysch basin are related to increased heat fluxes during the break‐up of Pangaea and are probably derived from the northwestern part of the Eastern Alps. The dominant Cretaceous zircon FT cooling ages reflect Eoalpine metamorphism in the Austroalpine realm.
Oceanic methane layers: the hydrocarbon seep bubble deposition hypothesis
Authors: Leifer I. , Judd A. G.
Published: March 2003

ABSTRACT Bubble plumes from hydrocarbon seeps drive upwelling flows in the water column that can disappear if the bubbles dissolve. This may lead to formation of a layer enriched in gases and substances transported by the bubbles, a process we term bubble deposition. A review of observed dissolved methane layers in the North Sea showed their existence in an area of active seeping pockmarks at a height of ∼ 20–30 m above the sea bed, well below the thermocline. To test the bubble deposition hypothesis, rising seep bubbles were simulated numerically. The model predicted a dissolution depth consistent with the observed methane layer for ∼ 2700‐µm‐radius bubbles. The model also predicted that bubbles smaller than 3400 µm dissolved subsurface, decreasing to 2000 µm for a 10‐cm s−1 upwelling flow. We speculate that this layer may be attractive to marine organisms. Although North Sea seeps are not oily, this mechanism also applies to oily bubbles from hydrocarbon seeps or a leaking undersea gas/oil pipeline. Thus bubble deposition can create a subsurface oil layer which rises far slower than either the bubble stream or droplets entrained in the stream.