bluuebunny/crossref_metadata_2025_split huggingface dataset:
Porewater reactions in the unsaturated zone with special reference to groundwater quality in England
Authors: Spears D. A. 
Published: May 2008

Summary

Porewater composition is an important control on the reactions leading to the formation of residual deposits. Although the mobility of porewater means it is not retained in ancient residual deposits, porewater movement through the unsaturated zone is a key factor in aquifer recharge. Porewater composition provides a sensitive means of monitoring reactions, and if infiltration has been operative over sufficient period of time whole rock changes may also be detected. Reactions involving different sedimentary fractions (resistate, hydrolysate and precipitate) are considered for infiltration into the Permo-Triassic sandstones and the Chalk of England. Externally derived elements may be identified and their behaviour in the unsaturated zone described. The examples considered are rainwater Na and Cl, fertilizer NO
3
and sewage effluent Cu, Zn and Ni.
A review of experimental weathering of basic igneous rocks
Authors: Cawsey David C. , Mellon Paul 
Published: May 2008

Summary
Attempts to reproduce and accelerate in the laboratory the effects of weathering on minerals are reviewed, together with some observational evidence of actual weathering effects. Laboratory experiments confirm the importance of water as the main agent of chemical weathering and that the progress of weathering is controlled by drainage, oxidation and pH. Some practical applications of accelerated weathering to engineering problems are briefly described, including a short description of the authors’ own work. The relative importance of chemical and physical weathering processes is considered briefly.
Kaolinisation and the formation of silicified wood on late Jurassic Gondwana surfaces
Authors: Wopfner H. 
Published: May 2008

Summary

In some parts of Australia and Africa intense kaolinisation took place on late Jurassic land surfaces, transforming considerable thicknesses of bedrock into masses of pure kaolin and quartz. Overlying these surfaces occur fluviatile, kaolinitic sandstones of late Jurassic or earliest Cretaceous age. They contain an abundance of silicified wood, including whole trunks of trees. The formation of silicified wood has previously been attributed to hot and arid desert environments, but in the examples described here, silicification proceeded under constantly high groundwater levels, requiring humid and probably warm climatic conditions. Silica was liberated by the kaolinisation of silicate minerals. Humic acids, produced during the initial decay of the fossil timber provided the low pH microenvironment for the fixation of SiO
2
.
Kaolinitic weathering profiles in Brittany: genesis and economic importance
Authors: Esteoule-Choux J. 
Published: May 2008

Summary
In Brittany, kaolinitic weathering profiles are developed on a variety of sedimentary, metamorphic and igneous rocks. In many places, laterite is associated with ironstone and/or silicified horizons. These profiles developed during the Cretaceous and Eocene, under hot wet climates: some of them are important commercial deposits.
The origin and occurrence of Devon Ball Clays
Authors: Vincent A. 
Published: May 2008

Summary

Valuable deposits of two types of kaolinitic clay (China Clay and Ball Clay), are found in the South-west of England.
China Clay
is comparatively coarse grained, well-ordered kaolinite derived from granite. Kaolinite particles are also derived from weathering of other country rocks, but such particles are fine-grained, disordered kaolinite. The properties of the two types of kaolinite are different. The two sedimentary
Ball Clay
basins of Devonshire occur in association with the Sticklepath Fault system. The properties of the various seams depend on the provenance of the kaolinite particles and the complex sedimentology of the two basins.
The Ayrshire Bauxitic Clay: an allochthonous deposit?
Authors: Monro S. K. , Loughnan F. C. , Walker M. C. 
Published: May 2008

Summary
Since the original study of the Ayrshire Bauxitic Clay by Wilson in 1922, new sections have been examined in both quarries and boreholes. It has also been suggested that the Ayrshire Bauxitic Clay is, in effect, a typical flint clay comparable with those of North America, South Africa, Australia and elsewhere. A re-examination of the outcrop and borehole evidence has been undertaken with a detailed chemical, mineralogical and petrographical study of the core of a bore that penetrated both the Ayrshire Bauxitic Clay and associated altered basalts. The study presents a body of evidence which suggests that, in part at least, the Ayrshire Bauxitic Clay is allochthonous in origin.
A low level laterite profile from Uganda and its relevance to the question of parent material influence on the chemical composition of laterites
Authors: McFarlane M. J. 
Published: May 2008

Summary
A 78 foot (24 m) ‘low level’ laterite profile from Tira, in Busia District, Uganda, is described. Mineral and chemical progressions, from the parent rock through saprolite and into the laterite, indicate its residual development. The chemical compositions of the residuum and the parent material are compared with further data from Uganda and other published results in order to assess the importance of the Fe, Al and quartz content of parent rocks in determining the chemical composition of a laterite. Quartz-richness of parent material does not appear to be disadvantageous for bauxite formation. Neither is Al-richness advantageous. This leads to the conclusion that the absence of bauxite in Uganda may be attributed to unfavourable leaching conditions rather than, as formerly believed, to the absence of suitable parent rocks.
Geochemistry of a nickeliferous laterite profile, Liberdade, Brazil
Authors: Esson J. 
Published: May 2008

Summary

The 23 samples studied represent a complete vertical profile, 11 m thick, from topsoil to bedrock. Multiple bedrock samples were collected to obtain good estimates of bedrock variability and bulk composition. Nineteen of the 22 major and trace elements studied fall into five behavioural groups within each of which all element pairs show strong positive correlations: (1) Al, Ti, V, Nb and Zr are very highly enriched (factors 20–65 relative to bedrock) in horizon B; (2) Fe, Cr, Sc, Cu and Ce are also strongly enriched (factors 4–40) in horizon B, but show slightly greater enrichment (factors 10–50) in horizon C; (3) Ni, Y, La, Nd and Zn are characterized by concentrations (enrichment factors 8–90) in horizon C of 5–10 times their levels in horizon B; (4) Mn and Co are intermediate between (2) and (3); (5) Si and Mg are strongly depleted in all soil horizons. A mass-balance model, based on quantitative Ti retention, gives relative wt% losses over the profile as a whole of MgO 99.5, Na
2
O 99.3, CaO 98.5, SiO
2
98.3, K
2
O 96, NiO 91, CoO 89, MnO 88, Cr
2
O
3
83, Fe
2
O
3
79, Sc 78, Zn 75, La 69, Ce 65, Al 59, V 57, Nb 40, Nd 19, Y 12, TiO
2
0. Zr and Cu show
ca
. 10% relative gains, indicating stronger retention than Ti.
In situ
leaching of an estimated serpentinite thickness in excess of 200 m is required to produce 11 m of residual laterite.
Post-depositional reddening of late Quaternary coastal dune sands, north-eastern Australia
Authors: Pye K. 
Published: May 2008

Summary
Deeply weathered quartz sand dunes of late Quaternary age occur at Cape Bedford and Cape Flattery on the seasonally humid tropical east coast of North Queensland, Australia. Many dunes have deep podzolic profiles with reddened B horizons up to 8 m thick. The red colour is produced by iron oxides and hydroxides which, together with kaolinite and minor gibbsite, form interstitial matrix and cutans on quartz grains. The red sands are generally uncemented, but nodular ironstone layers are present in some sections. Radiocarbon dating has shown that one red podzol profile near Cape Flattery has formed in the last 7500 C-14 years. Progressive podzolization has removed much of the iron pigment from the oldest dunes in the area, which are >48 000 C-14 years old. These dunes are degraded and contain subsurface horizons which are cemented by humate.
Origin of red beds in a moist tropical climate (Etruria Formation, Upper Carboniferous, UK)
Authors: Besly B. M. , Turner P. 
Published: May 2008

Summary
The Etruria Formation is a Westphalian mudstone-dominated red bed succession, which is interdigitated with, and overlies coal-bearing paralic sediments in Central England. Sedimentological studies indicate that the formation mainly comprises swamp and muddy alluvial plain deposits. The distribution of red beds shows that the red coloration formed in areas of improved drainage soon after deposition, and was associated with the formation of complex palaeosols. The occurrence of coals and humid climate floras within the red bed succession suggests that the onset of oxidizing conditions was not the result of climatic change. There are no fundamental differences in the mineralogy of associated grey and red beds: both have distinctive residual characteristics, and consist mostly of kaolinite and quartz. The alluvium was derived from intensely weathered source areas, and was reddened during and soon after deposition by the dehydration of detrital ferric hydroxides and the oxidation of ferrous iron associated with organic material. Palaeomagnetic results support the view that reddening took place shortly after deposition, when the area lay in close proximity to the Carboniferous equator. The Etruria Formation thus provides an excellent example of the genesis of red beds as muddy alluvium under moist tropical climatic conditions.
Environment of silcrete formation: a comparison of examples from Australia and the Cologne Embayment, West Germany
Authors: Wopfner H. 
Published: May 2008

Summary

Silcretes are subdivided into three main groups, depending on whether their matrix has been formed by: I crystalline quartz growth; II cryptocrystalline quartz aggregation or III formation of cristobalitic-tridymitic silica (opal CT). Groups I and II silcretes are usually associated with intense kaolinisation and formed in low-pH environments, where Al
2
O
3
solubility exceeds that of SiO
2
. Palludal regimes in moist/warm climates provide such conditions. Group I silcretes are purely diagenetic, whereas pedogenic processes play an essential role in the formation of Group II silcretes. Group III silcretes, composed primarily of cristobalite lepispheres, developed primarily under oxidising conditions in arid, alkaline environments. These genetic models, originally developed from observations on Australian silcretes, are applied with Tertiary silcretes of the Cologne Embayment in western Germany. SEM investigations of grain surfaces and fabrics of these so-called ‘lignite quartzites’ show that they are comparable with the Australian examples, with the exception that cristobalite-lepispheres are not exclusive to Group III silcretes, but occur also in porcellanitic interlayers of Group I silcretes, where the parent material consists of very fine grained siliciclastics.
Silcrete in Western Australia: geomorphological settings, textures, structures, and their genetic implications
Authors: van de Graaff W. J. E. 
Published: May 2008

Summary

Tertiary silcrete and laterite are extensively preserved in Western Australia in low-relief landscapes. Silcrete is best developed on topographic highs developed on fluviatile sands which overly radiolarites or deeply kaolinised claystones. Laterite occurs topographically lower and is generally developed on fine-grained bed rock. Lateral transition of silcrete to laterite indicates that these duricrusts form a soil catena. Cone structures in the silcretes indicate strongly evaporitic, dry conditions, whereas solution pipes in duricrust profiles indicate humid conditions. The silcrete/laterite catena thus indicates a strongly seasonal, hot, and humid climate, with rainfall probably in excess of 1000 mm yr
−1
.
Geochemistry of weathering profile silcretes, southern Cape Province, South Africa
Authors: Summerfield M. A. 
Published: May 2008

Summary
Silcrete of Cenozoic age associated with deep weathering profiles occurs on residual surfaces along the coastal belt of southern Cape Province. Petrographic and geochemical evidence indicates loss of aluminium and enrichment of silica and titanium during silcrete formation. Silica released locally within the weathering profile was apparently precipitated in a zone of restricted drainage close to the water-table where a low pH environment allowed the removal of aluminium and the migration and concentration of titanium. Silcrete formation probably occurred in a humid tropical or subtropical environment with minimal local relief.
Pliocene channel calcrete and suspenparallel drainage in West Texas and New Mexico
Authors: Reeves C. C. 
Published: May 2008

Summary
The recent discovery of two calcium carbonate-cemented drainage channels in the Pliocene Ogallala section of the Southern High Plains, Texas and New Mexico, indicates that Ogallala drainage channels were commonly cemented with calcium carbonate, due to leaching of calcrete from adjacent Ogallala sands. Parallel drainage lines near Lovington, New Mexico, originally thought to represent calcrete incisement along ancient dune swales, are now interpreted as an example of recent drainage between a suspenparallel drainage pattern in bas-relief.
Ancient duricrusts and related rocks in perspective: a contribution from the Old Red Sandstone
Authors: Parnell John 
Published: May 2008

Summary
Calcretes are abundant in continental Devonian (Old Red Sandstone) rocks, occurring both within the sequence and at the basal unconformity. Basal limestones in the Orcadian Basin also include algal deposits and fissure linings, all of which can be considered as a single phase of carbonate precipitation and growth. A prominent silcrete in Orkney replaces both rudites and chert-bearing lacustrine laminites. Silcrete and calcrete are examined in a wider context of chemical sedimentation in lacustrine rocks. The effects of weathering processes in these rocks may be combined or confused with those of algal processes. A silicified plant-bearing sequence at Rhynie displays the same diagenetic features as the Orkney silcrete. Limited metalliferous and bituminous enrichments are recorded in the largest ORS duricrusts. A basal sequence at Dalroy exemplifies the possible confusion between weathering concentrations and mineral deposits trapped at an unconformity surface. Barite is a common component of some duricrusts. Duricrust formation is part of a range of sedimentary replacement and cementation phenomena which may be difficult to distinguish in ancient rocks.
A process-response model for the formation of pedogenic calcretes
Authors: Klappa Colin F. 
Published: May 2008

Summary
The compositional and fabric evolution of pedogenic calcretes is viewed as a process-response model involving inorganic and organic soil-forming processes on the one hand, and diagenetic, rock-forming processes on the other; the resulting battle being expressed as six evolutionary stages: (1) preparation of host material; (2) soil formation and horizon differentiation; (3) accumulation of calcium carbonate; (4) profile development; (5) induration; and (6) reworking. In nature, some stages may be repeated or reversed; others may be omitted. Emphasis is given to the role of organic activity which determines largely the morphology of pedogenic calcrete profiles and which controls the direction and extent of profile development.
Stable isotope abundances in calcretes
Authors: Talma A. S. , Netterberg F. 
Published: May 2008

Summary

About 300 published and unpublished measurements of carbon and oxygen stable isotope ratios of calcretes are compared in an attempt to define general trends. The δ
13
C values of the carbonates range from − 12 to + 4‰ PDB. On a global scale the main factor responsible for the average
13
C content of calcrete in an area appears to be the
13
C content of the dominant plants in the region. No correlation could be found between
13
C contents and radiocarbon age. The carbonate δ
18
O values range from − 9 to +3‰ PDB. On a global scale, the factors discussed as possibly responsible for the
18
O content of a calcrete are the
18
O content of the local rainfall, temperature, and the extent to which the water underwent free surface evaporation before or during calcrete formation. Little or no correlation was found between
13
C or
18
O contents and rainfall, temperature, or evaporation rate on a world basis. Some relation between the
18
O content of calcrete and rain on a regional basis was confirmed. The range of
13
C and
18
O values suggest a diversity of origins and environments of formation.
A Geotechnical classification of calcretes and other pedocretes
Authors: Netterberg F. , Caiger J. H. 
Published: May 2008

Summary
Authigenic calcareous accumulations within regoliths can be simply classified for geotechnical purposes as calcareous soils, calcified soils, powder calcretes, nodular calcretes, honeycomb calcretes, hardpan calcretes, and calcrete boulders and cobbles. Each of these categories represents a particular stage in the growth or weathering of a calcrete horizon and possesses a significantly different range of geotechnical properties. A similar classification can be applied to other pedocretes.
Karstic residual fluorite-baryte deposits at two localities in Derbyshire
Authors: Shaw R. P. 
Published: May 2008

Summary
Various karst processes may rework primary mineralization producing secondary ore deposits in a variety of karstic cavities both on the surface and underground. Two surface localities, on Bonsall Moor, near Matlock, and near Castleton are filled with sediments containing locally derived fluorite and baryte clasts, in sufficient quantity to be worked as ore deposits. The associated clastic sediments are of Pleistocene fluvioglacial origin.
Cenozoic pedogenesis and landform development in south-east England
Authors: Catt John A. 
Published: May 2008

Summary
Soils are useful stratigraphically because they mark land surfaces of significant duration. They also provide valuable palaeo-environmental evidence complementary to that obtained from sedimentary successions. In south-east England both buried and unburied soils are broadly divided on field morphology and petrographic characteristics into those formed during the Flandrian Stage and others (palaeo-argillic soils) dating from the Cromerian and later interglacial stages. Even where the latter are derived from pre-Quaternary deposits, as on the Chalk dipslope, their profile characteristics and stratigraphic relationships to remnants of early Quaternary marine deposits suggest development during the Quaternary rather than in the Tertiary. Although most major landscape features were probably inherited from the late Tertiary, the entire land surface of south-east England suffered significant Quaternary erosion, and there are no definite relics of Tertiary pedogenesis.
Nutlin-3a Activates p53 to Both Down-regulate Inhibitor of Growth 2 and Up-regulate mir-34a, mir-34b, and mir-34c Expression, and Induce Senescence
Authors: Kumamoto Kensuke , Spillare Elisa A. , Fujita Kaori , Horikawa Izumi , Yamashita Taro , Appella Ettore , Nagashima Makoto , Takenoshita Seiichi , Yokota Jun , Harris Curtis C. 
Published: May 2008

Abstract
Nutlin-3, an MDM2 inhibitor, activates p53, resulting in several types of cancer cells undergoing apoptosis. Although p53 is mutated or deleted in ∼50% of all cancers, p53 is still functionally active in the other 50%. Consequently, nutlin-3 and similar drugs could be candidates for neoadjuvant therapy in cancers with a functional p53. Cellular senescence is also a phenotype induced by p53 activation and plays a critical role in protecting against tumor development. In this report, we found that nutlin-3a can induce senescence in normal human fibroblasts. Nutlin-3a activated and repressed a large number of p53-dependent genes, including those encoding microRNAs. mir-34a, mir-34b, and mir-34c, which have recently been shown to be downstream effectors of p53-mediated senescence, were up-regulated, and inhibitor of growth 2 (ING2) expression was suppressed by nutlin-3a treatment. Two candidates for a p53-DNA binding consensus sequence were found in the ING2 promoter regulatory region; thus, we performed chromatin immunoprecipitation and electrophoretic mobility shift assays and confirmed p53 binding directly to those sites. In addition, the luciferase activity of a construct containing the ING2 regulatory region was repressed after p53 activation. Antisense knockdown of ING2 induces p53-independent senescence, whereas overexpression of ING2 induces p53-dependent senescence. Taken together, we conclude that nutlin-3a induces senescence through p53 activation in normal human fibroblasts, and p53-mediated mir34a, mir34b, and mir34c up-regulation and ING2 down-regulation may be involved in the senescence pathway. [Cancer Res 2008;68(9):3193–203]
CD151 Accelerates Breast Cancer by Regulating α6 Integrin Function, Signaling, and Molecular Organization
Authors: Yang Xiuwei H. , Richardson Andrea L. , Torres-Arzayus Maria I. , Zhou Pengcheng , Sharma Chandan , Kazarov Alexander R. , Andzelm Milena M. , Strominger Jack L. , Brown Myles , Hemler Martin E. 
Published: May 2008

AbstractCD151, a master regulator of laminin-binding integrins (α6β4, α6β1, and α3β1), assembles these integrins into complexes called tetraspanin-enriched microdomains. CD151 protein expression is elevated in 31% of human breast cancers and is even more elevated in high-grade (40%) and estrogen receptor–negative (45%) subtypes. The latter includes triple-negative (estrogen receptor, progesterone receptor, and HER2 negative) basal-like tumors. CD151 ablation markedly reduced basal-like mammary cell migration, invasion, spreading, and signaling (through FAK, Rac1, and lck) while disrupting epidermal growth factor receptor (EGFR)-α6 integrin collaboration. Underlying these defects, CD151 ablation redistributed α6β4 integrins subcellularly and severed molecular links between integrins and tetraspanin-enriched microdomains. In a prototypical basal-like mammary tumor line, CD151 ablation notably delayed tumor progression in ectopic and orthotopic xenograft models. These results (a) establish that CD151-α6 integrin complexes play a functional role in basal-like mammary tumor progression; (b) emphasize that α6 integrins function via CD151 linkage in the context of tetraspanin-enriched microdomains; and (c) point to potential relevance of CD151 as a high-priority therapeutic target, with relative selectivity (compared with laminin-binding integrins) for pathologic rather than normal physiology. [Cancer Res 2008;68(9):3204–13]