bluuebunny/crossref_metadata_2025_split huggingface dataset:
Development of the North Island Subduction System, New Zealand
Authors: van der Lingen Gerrit J. 
Published: May 2008

Summary

Subduction of the Pacific plate underneath the North Island of New Zealand began near the beginning of the Neogene, when the Tonga-Kermadec Subduction System propagated southwards into the New Zealand continental crustal block, together with the southwards migration of the relative pole of rotation between the Pacific and Australian plates. Many geological and geophysical aspects of the North Island, both on land and offshore, are in agreement with models of subduction systems from elsewhere. Several NE-trending zones can be distinguished: Taupo Volcanic Zone (volcanic arc), Axial Ranges (exposed part of arc massif), East Coast Depression (forearc basin), Coastal Ranges (structural high of subduction complex), continental shelf and slope (trough-inner-slope of subduction complex). A west-dipping Benioff zone underlies the volcanic arc and arc massif. A negative gravity anomaly coincides with the surface extension of the Benioff zone. However, no subduction trench exists below the negative gravity anomaly.
Sensu stricto
, The Hikurangi Trough, to the east of the subduction complex, is not a subduction trench.

The forearc basin and subduction complex are riding passively on top of the Pacific plate to the east of the Benioff zone. The forearc basin initially was shallow marine, but subsequently was filled with coarse debris shed from the rising arc massif, and is now above water. The subduction complex consists of highly deformed autochthonous Cretaceous-Palaeogene strata, possibly deposited in a pre-subduction continental borderland. Accreted oceanic sediments have not been recorded, but may be present in the lower part of the subduction complex, or, to a large degree, may have been subducted. During the formation of the subduction complex, small basins were created by elongate narrow structural ridges parallel to the trough-inner-slope. Several are now exposed in the Coastal Ranges structural high. Their sedimentary fills comprise sediment gravity flow deposits, hemipelagic muds, and arc-derived ash. Similar sedimentary facies have been cored in present-day offshore slope basins. Some sediment gravity flows reach the Hikurangi Trough via submarine canyons, bypassing the slope.
A directional, morphological and geophysical break exists between the North Island and Kermadec subduction systems, probably caused by the Vening Meinesz Fracture Zone.
Early-upper Miocene rhyolitic tuff beds in trough-inner-slope flysch basins are the first sign of volcanic arc activity. They cannot have come from the Quaternary Taupo Volcanic Zone, but were probably derived from the upper Miocene Coromandel Arc further to the NW. As subduction is oblique, strike-slip movement has moved the forearc region east of the Axial Ranges from a position closer to the Coromandel Arc to its present situation.
The Late Cretaceous-Cenozoic history of western Baluchistan Pakistan—the northern margin of the Makran subduction complex
Authors: Arthurton Russell S. , Farah Abul , Ahmed Wahiduddin 
Published: May 2008

Summary
The study area lies some 400 km N of the Makran coast, and extends westwards for some 450 km from the Chaman Fault, a major sinistral transform fracture zone which marks the suture between the Eurasian and Indian plates. It lies to the north of the Makran ranges of Tertiary flysch, and flanks the southern margin of a stable, aseismic area known as the Dashi-i-Margo block.
The Makran region as a whole has been interpreted as an accretionary prism of Late Cretaceous to Holocene age, resulting from the northward subduction of oceanic lithosphere. The geological record of the study area is consistent with such an interpretation, for the period Late Cretaceous-Palaeocene at least.
Rapid northward subduction during the Late Cretaceous gave rise to profuse andesitic volcanism on the sub-parallel, ENE-trending arc massifs of the Chagai Hills and Ras Koh geanticlines. The waning of this volcanism during the Maestrichtian coincided with the accumulation and deformation of flysch sediments in a trench which extended from Mirjawa to the south of Ras Koh; also with thick forearc sedimentation in the Dalbandin Trough, between the geanticlines.
In late Palaeocene times, deformed flysch—interpreted as a subduction complex—was elevated to form a structural high in the Mirjawa range. In the western Ras Koh, the flysch, along with ultramafic slices, became emplaced against the arc massif to form a new landmass. This emplacement may have been a result of a late Palaeocene collision between the northward-migrating Indian continental plate and the continental lithosphere of the Dasht-i-Margo block, the Ras Koh flysch belt taking the brunt of the initial impact.
The principal forearc faults have regular, arcuate traces which, in the south-west, parallel the structural grain of the Mirjawa flysch belt. Movement on the faults influenced sedimentation in the forearc, particularly during the Eocene and Miocene. There is evidence of tensional transform movement in Eocene times. The forearc faults were especially active during the Pliocene. Movement across them during this period was compressional and associated with major folding, particularly in the Dalbandin Trough. The trend of this folding may imply dextral transform displacement within the trough.
The Coastal Belt of the Franciscan: youngest phase of northern California subduction
Authors: Bachman Steven B. 
Published: May 2008

Summary
The Coastal Belt of the Franciscan complex represents the latest Cretaceous to middle Tertiary part of the accretionary prism of an arc-trench system in northern California. On the Mendocino coast, both deformed slope and trench deposits and much less deformed slope basin deposits are recognized. Deformation increases with depth in the slope deposits, towards the contact with the accretionary prism. In the accretionary prism, bands of deformed rocks from tens of metres to kilometres in width suggest major zones of shearing. Stratigraphic tops of beds face eastward, yet palaeontological ages young westward; imbricate stacking is suggested by these relationships. Stratigraphical tops and palaeontological ages indicate that the slope basin deposits are in normal stratigraphic sequence.
Facies in the accretionary prism may represent trench fill, abyssal plain, feeder channel, and small fan deposits that were accreted to the leading edge of the continent and may also include slope deposits that were deformed during progressive deformation of the accretionary prism. The less deformed slope deposits may have been deposited as slope basin turbidites, small fans, and channels. South- and south-westward-directed palaeocurrent indicators and sandstone petrology suggest sediment transport from the Klamath Mountains and Oregon across the shelf and down the slope and/or along the trench axis.
Composition of modern deep-sea sands from arc-related basins
Authors: Maynard J. Barry , Valloni Renzo , Yu Ho-Shing 
Published: May 2008

Summary
Petrographic and chemical examination of modern deep-sea sands shows a clear distinction between active and passive plate-tectonic settings. Among active settings, sands from forearc basins of island arcs and basins from strike-slip continental margins can be distinguished, but those from other arc-related settings overlap considerably in composition. In particular, sands from continental margin subduction zones and those from the backarc of island arcs appear to be indistinguishable.
Chemically, arc-related sands are very close in composition to ancient greywacke sandstones. For instance, sodium almost always exceeds potassium. Thus it is not necessary for sodium to be added to sands diagenetically to make greywackes, as has been suggested.
Initiation of subduction zones: implications for arc evolution and ophiolite development
Authors: Karig D. E. 
Published: May 2008

Summary
The initial location of trenches with respect to continental margins is a critical factor in the nature of the forearc region and its subsequent evolution, as well as for the interpretation of ophiolites. Although recent studies of ancient margins and highly evolved arcs suggest that wide strips of oceanic crust are commonly trapped between the trench and volcanic arc, review of young active arcs does not support this conclusion. Neogene trenches have formed predominantly very close to the crustal interface between oceanic crust and continental or older island arc crust. A few arcs have developed along transform zones, but none can be identified as having formed by breakage within an oceanic plate. Apparently the high strength of normal oceanic lithosphere causes the initial fracture to utilize pre-existing zones of weakness or pre-stressing, such as the downbowed and fractured crustal interfaces along passive margins. There seems to be no physical basis for the initial rupture to form smooth, large radius arcs, thereby trapping oceanic crust in re-entrants. Moreover, oceanic crust or ophiolites originating adjacent to a continental or arc margin ought to betray that heritage by a high terrigenous or volcaniclastic component in their overlying sediment. Large ophiolite sheets that can be interpreted as forearc slabs may develop in areas with relatively unusual plate geometries, as where oceanic spreading zones cut diagonally across the forearc. Disrupted ophiolites could, in many cases, represent slices of oceanic crust and upper mantle accreted to and responsible for the growth of oceanic arcs. Evidence for accreted slices in the Mariana arc and the range of forearc geometries among oceanic arcs allow construction of an evolutionary sequence in which an initial steep and narrow trench shape is differentiated into upper and lower sections by intermittent accretion of oceanic crustal slices. As a result, the slope apron on the upper section rotates arcward and can rise to form a basin as is displayed in the southern Middle America arc.
Base metal concentrations in kaolinised and silicified lavas of the Central Burma volcanics
Authors: Marshall T. R. , Amos B. J. , Stephenson D. 
Published: May 2008

Summary
Detailed mapping and limited geochemical sampling of a Lower Pliocene trachyandesite-sediment-tuff sequence reveals two juxtaposed but distinct kaolinised sequences caused by tropical weathering and hydrothermal activity. The stratigraphy and sequence of alteration in the lower Taungni section is difficult to establish. The kaolinised rocks are characterized by high lead and arsenic content and contain large irregular masses of silica. Kaolinisation resulted either directly from metalliferous hydrothermal activity or from acidic fluids released by oxidation of sulphides. The upper, well-bedded Kyauktaga section shows regular redistribution of silica resembling that of the silcrete profile and vertical base metal zoning attributable to groundwater movement.
Palaeoenvironment of lateritic bauxites with vertical and lateral differentiation
Authors: Valeton Ida 
Published: May 2008

Summary
Formation of lateritic bauxites of the type described in this paper occurs world-wide in Cretaceous and Tertiary coastal plains. The bauxites form elongate belts, sometimes hundreds of kilometres long, parallel to Lower Tertiary shorelines in India and South America and their distribution is not related to a particular mineralogical composition of the parent rock. The lateral movement of the major elements Al, Si, Fe, Ti is dependent on a high level and flow of groundwater. Varying efficiency of subsurface drainage produces lateral facies variations. Interfingering of marine and continental facies indicate a sea-land transition zone where the type of sediments also varies with minor tectonic movements or sea-level changes. A typical sediment association is found in India, Africa, South and North America. It consists of (i) red beds rich in detrital and dissolved material of reworked laterites, (ii) lacustrine sediments and hypersaline precipitates, (iii) lignites intercalated with marine clays, layers of siderite, pyrite, marcasite and jarosite, and (iv) marine chemical sediments rich in oolitic iron ores or glauconite. A model is developed to account for element distributions in lateritic bauxites in terms of groundwater levels and flow. Finally it is shown that many high-level bauxites are formed in coastal plains and that they are subsequently uplifted to their present altitude.
Reddening of tropical coastal dune sands
Authors: Gardner R. 
Published: May 2008

Summary

This paper describes the pedological processes, including that of reddening, in latosol formation in dune sands on humid tropical coastlines. A time-scale is established for these processes in South-east India, Sri Lanka and the Natal Province of the Republic of South Africa. Weathering
in situ
of the dune sands has occurred since their deposition in all three locations. Evidence from thin section and TEM analyses shows that detrital addition of clay minerals and iron oxides has been negligible. The major pedogenic processes (as shown by thin section, SEM, TEM, XRD and chemical analyses) in the formation of the latosols in the field areas are: weathering of garnet, feldspar, hornblende and opaque minerals; formation of kaolinite and illite clay minerals; oxidation of iron to haematite, and loss of carbonate and partial removal of silica from weathered horizons, followed by their deposition lower down the profile in some cases. Dating of the red latosols (2.5 YR 4/6-10R 4/8), radiometrically and using archaeological evidence, indicates that formation to depths of 10 m has taken place in under 20,000 years in the coastal dune sands in the field areas. It is suggested that reddening of desert sands by mineral breakdown could take place on time-scales that are much shorter than has previously been assumed.
Concentration of uranium and vanadium in calcretes and gypcretes
Authors: Carlisle Donald 
Published: May 2008

Summary
Uranium ore-bearing calcretes (in Western Australia and Namibia) are non-pedogenic. They result from lateral transport rather than vertical redistribution of components and they develop mainly in the capillary fringe along the axes of large stable drainages with low gradients under uniquely arid climates. Valley, deltaic and lake margin calcretes and dolocretes in Western Australia are part of an orderly succession from silica hardpan to playa salts. Distributions of uraniferous non-pedogenic and non-uraniferous pedogenic calcretes are mutually exclusive. Carnotite, the only ore mineral, results from: (1) evaporative concentration of U, V and/or K; (2) destabilization of uranyl carbonate complexes consequent to evaporative and common-ion precipitation of Ca/Mg carbonate; and (3) oxidation of V(IV) to V(V) in upwelling groundwater. Richest concentrations occur where groundwaters rise toward the evaporative zone. Pedogenic calcretes may inhibit ore-grade concentration. Carnotite in gypcrete is economically significant but less common.
Functional Assays for Classification ofBRCA2Variants of Uncertain Significance
Authors: Farrugia Daniel J. , Agarwal Mukesh K. , Pankratz Vernon S. , Deffenbaugh Amie M. , Pruss Dmitry , Frye Cynthia , Wadum Linda , Johnson Kiley , Mentlick Jennifer , Tavtigian Sean V. , Goldgar David E. , Couch Fergus J. 
Published: May 2008

AbstractThe assessment of the influence of many rare BRCA2 missense mutations on cancer risk has proved difficult. A multifactorial likelihood model that predicts the odds of cancer causality for missense variants is effective, but is limited by the availability of family data. As an alternative, we developed functional assays that measure the influence of missense mutations on the ability of BRCA2 to repair DNA damage by homologous recombination and to control centriole amplification. We evaluated 22 missense mutations from the BRCA2 DNA binding domain (DBD) that were identified in multiple breast cancer families using these assays and compared the results with those from the likelihood model. Thirteen variants inactivated BRCA2 function in at least one assay; two others truncated BRCA2 by aberrant splicing; and seven had no effect on BRCA2 function. Of 10 variants with odds in favor of causality in the likelihood model of 50:1 or more and a posterior probability of pathogenicity of 0.99, eight inactivated BRCA2 function and the other two caused splicing defects. Four variants and four controls displaying odds in favor of neutrality of 50:1 and posterior probabilities of pathogenicity of at least 1 × 10−3 had no effect on function in either assay. The strong correlation between the functional assays and likelihood model data suggests that these functional assays are an excellent method for identifying inactivating missense mutations in the BRCA2 DBD and that the assays may be a useful addition to models that predict the likelihood of cancer in carriers of missense mutations. [Cancer Res 2008;68(9):3523–31]
Mechanisms of Antileukemic Activity of the Novel Bcl-2 Homology Domain-3 Mimetic GX15-070 (Obatoclax)
Authors: Konopleva Marina , Watt Julie , Contractor Rooha , Tsao Twee , Harris David , Estrov Zeev , Bornmann William , Kantarjian Hagop , Viallet Jean , Samudio Ismael , Andreeff Michael 
Published: May 2008

AbstractIn this study, we investigated the mechanism of apoptosis induction of obatoclax (GX15-070), a novel Bcl-2 homology domain-3 (BH3) mimetic, in acute myeloid leukemia (AML) cell lines and primary AML samples. Obatoclax inhibited cell growth of HL-60, U937, OCI-AML3, and KG-1 cell lines. Apoptosis induction contributed to the observed antiproliferative effects at concentrations of this agent that mirror its affinity for antiapoptotic Bcl-2 proteins. We show that obatoclax can promote the release of cytochrome c from isolated leukemia cell mitochondria and that apoptosis induced by this agent is preceded by the release of Bak from Mcl-1, liberation of Bim from both Bcl-2 and Mcl-1, and the formation of an active Bak/Bax complex. Notably, apoptosis was diminished, but not fully prevented, in the absence of Bak/Bax or Bim, suggesting that obatoclax has additional targets that contribute to its cytotoxicity. At growth inhibitory doses that did not induce apoptosis or decrease viability, obatoclax induced an S-G2 cell-cycle block. Obatoclax induced apoptosis in AML CD34+ progenitor cells with an average IC50 of 3.59 ± 1.23 μmol/L although clonogenicity was inhibited at concentrations of 75 to 100 nmol/L. Obatoclax synergized with the novel BH3 mimetic ABT-737 to induce apoptosis in OCI-AML3 cells and synergistically induced apoptosis in combination with AraC in leukemic cell lines and in primary AML samples. In conclusion, we show that obatoclax potently induces apoptosis and decreases leukemia cell proliferation and may be used in a novel therapeutic strategy for AML alone and in combination with other targeted agents and chemotherapeutics. [Cancer Res 2008;68(9):3413–20]
How Dysregulated Colonic Crypt Dynamics Cause Stem Cell Overpopulation and Initiate Colon Cancer
Authors: Boman Bruce M. , Fields Jeremy Z. , Cavanaugh Kenneth L. , Guetter Arthur , Runquist Olaf A. 
Published: May 2008

AbstractBased on investigation of the earliest colonic tissue alteration in familial adenomatous polyposis (FAP) patients, we present the hypothesis that initiation of colorectal cancer by adenomatous polyposis coli (APC) mutation is mediated by dysregulation of two cellular mechanisms. One involves differentiation, which normally decreases the proportion (proliferative fraction) of colonic crypt cells that can proliferate; the other is a cell cycle mechanism that simultaneously increases the probability that proliferative cells are in S phase. In normal crypts, stem cells (SC) at the crypt bottom generate rapidly proliferating cells, which undergo differentiation while migrating up the crypt. Our modeling of normal crypts suggests that these transitions are mediated by mechanisms that regulate proliferative fraction and S-phase probability. In FAP crypts, the population of rapidly proliferating cells is shifted upwards, as indicated by the labeling index (LI; i.e., crypt distribution of cells in S phase). Our analysis of FAP indicates that these transitions are delayed because the proliferative fraction and S-phase probability change more slowly as a function of crypt level. This leads to expansion of the proliferative cell population, including a subpopulation that has a low frequency of S-phase cells. We previously reported that crypt SC overpopulation explains the LI shift. Here, we determine that SCs (or cells having high stemness) are proliferative cells with a low probability of being in S phase. Thus, dysregulation of mechanisms that control proliferative fraction and S-phase probability explains how APC mutations induce SC overpopulation at the crypt bottom, shift the rapidly proliferating cell population upwards, and initiate colon tumorigenesis. [Cancer Res 2008;68(9):3304–13]
Potential Use of Quantitative Tissue Phenotype to Predict Malignant Risk for Oral Premalignant Lesions
Authors: Guillaud Martial , Zhang Lewei , Poh Catherine , Rosin Miriam P. , MacAulay Calum 
Published: May 2008

AbstractThe importance of early diagnosis in improving mortality and morbidity rates of oral squamous cell carcinoma (SCC) has long been recognized. However, a major challenge for early diagnosis is our limited ability to differentiate oral premalignant lesions (OPL) at high risk of progressing into invasive SCC from those at low risk. We investigated the potential of quantitative tissue phenotype (QTP), measured by high-resolution image analysis, to identify severe dysplasia/carcinoma in situ (CIS; known to have an increased risk of progression) and to predict progression to cancer within hyperplasia or mild/moderate dysplasia. We generated a nuclear phenotype score (NPS), a combination of five nuclear morphometric features that best discriminate 4,027 “normal” nuclei (selected from 29 normal oral biopsies) from 4,298 “abnormal” nuclei (selected from 30 SCC biopsies). This NPS was then determined for a set of 69 OPLs. Severe dysplasia/CIS showed a significant increase in NPS compared with hyperplasia or mild/moderate dysplasia. However, within the latter group, elevated NPS was strongly associated with the presence of high-risk loss of heterozygosity (LOH) patterns. There was a statistical difference between NPS of hyperplasia or mild/moderate dysplasia that progressed to cancer and those that did not. Individuals with a high NPS had a 10-fold increase in relative risk of progression. In the multivariate Cox model, LOH and NPS together were the strongest predictors for cancer development. These data suggest that QTP could be used to identify lesions that require molecular evaluation and should be integrated with such approaches to facilitate the identification of hyperplasia or mild/moderate dysplasia OPLs at high risk of progression. [Cancer Res 2008;68(9):3099–107]