Physics and Chemistry of the Earth, Part A: Solid Earth and Geodesy最新文献

{"title":"Surface deformation induced by pluton emplacement: the case of Amiata (Italy)","authors":"V. Acocella ,&nbsp;G. Mulugeta","doi":"10.1016/S1464-1895(01)00065-5","DOIUrl":"https://doi.org/10.1016/S1464-1895(01)00065-5","url":null,"abstract":"<div><p>The Amiata area was uplifted during the Pliocene as a consequence of pluton emplacement in an extensional setting. In the Middle Pleistocene, a fissural eruption filled a depression within the uplifted area. Field analysis and analogue models are integrated to study the surface deformation induced by the emplacement of the buried pluton. Field work recognized a domed overburden, ≈2.5 km high and 35 × 50 km wide. Analogue models of pluton emplacement show three stages at the surface, which consist of: doming, development of a crestal depression and apical extrusion. Theoretical calculations suggest that the bending stresses and the stretching of the brittle layer during doming induce the development of the apical depression in experiments and nature. This, in turn, is responsible for a localized decompression, enhancing extrusion. The integrated data suggests that doming, crestal depression and fissural volcanism at Amiata are sequential features due to pluton emplacement in an extensional setting.</p></div>","PeriodicalId":101024,"journal":{"name":"Physics and Chemistry of the Earth, Part A: Solid Earth and Geodesy","volume":"26 4","pages":"Pages 355-362"},"PeriodicalIF":0.0,"publicationDate":"2001-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1464-1895(01)00065-5","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72283227","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Syntectonic melt pathways in granitic gneisses, and melt-induced transitions in deformation mechanisms","authors":"C.L. Rosenberg ,&nbsp;A. Berger","doi":"10.1016/S1464-1895(01)00058-8","DOIUrl":"https://doi.org/10.1016/S1464-1895(01)00058-8","url":null,"abstract":"<div><p>Partial melting of granodioritic gneisses in the contact aureole of the Bergell Pluton (Central Alps) occurred during regional deformation. Melting occurred in the presence of water, which was released from the pluton. The presence of melt is evidenced by local segregations of granite in shear zones, veins and dykes, and by grain-scale interstitial films of K-feldspar and quartz that do not occur in the unmelted protolith. These films are oriented parallel, as well as perpendicular to the foliation plane. In contrast, on the outcrop scale, cm-wide leucosome veins are oriented almost exclusively parallel to the foliation plane, indicating foliation-parallel flow. The partially molten granitic rocks contain dm-long clasts of restitic, well-foliated gneiss, showing a higher competence than their granitic matrix. K-feldspar is lacking in these clasts, the microstructure of which is characterized by elongate aggregates of quartz and feldspar, both dynamically recrystallized. In contrast, the granitic matrix is characterised by a random distribution of minerals, whith a shape preferred orientation defining a weak foliation. These microstructures are indicative of granular flow, whereas the microstructures of the clasts indicate dislocation creep involving dynamic recrystallization. The presence of K-feldspar controls the onset of melting and thus the transition from dislocation creep to granular flow. The weakening resulting from this transition is indicated by the formation of strong clasts in a weaker matrix.</p></div>","PeriodicalId":101024,"journal":{"name":"Physics and Chemistry of the Earth, Part A: Solid Earth and Geodesy","volume":"26 4","pages":"Pages 287-293"},"PeriodicalIF":0.0,"publicationDate":"2001-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1464-1895(01)00058-8","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72283217","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Melt segragation, pervasive melt migration and magma mobility in the continental crust: the structural record from pores to orogens","authors":"O. Vanderhaeghe","doi":"10.1016/S1464-1895(01)00048-5","DOIUrl":"https://doi.org/10.1016/S1464-1895(01)00048-5","url":null,"abstract":"<div><p>Structural analysis of migmatites based on the distribution and proportion of the granitic fraction at the outcrop scale is taken as a guide to decipher the behavior of partially molten rocks during orogenesis. This approach evaluates the various mechanisms that control melt segregation and magma mobility from pores to orogens. During partial melting, the first liquid appears at grain interfaces but such textures are rarely preserved in igneous rocks. Mechanisms of melt movement are scale-dependent and it is important to distinguish melt segregation at grain-scale from melt migration which occurs over larger distances. Melt segregation is controlled by melt connectivity and ubiquitous localization of granites in structurally-controlled dilatant sites provides evidence of the efficiency of melt segregation at the outcrop scale, probably achieved by porous flow at the grain scale. Magma mobility is controlled by the continuity of the solid framework which controls the rheologic threshold at the transition from solid-dominated metatexites to liquid-dominated diatexites. The presence of laccoliths of homogeneous leucogranite, emplaced at higher structural levels far from their source, indicates the efficiency of melt migration beyond the grain scale. The transition zone between diatexites (melt source) and granitic laccoliths (melt sink) is characterized by a network of granitic veins centimeter- to meter-thick. The geometric characteristics of this network suggest that, depending on structural level and the competency contrast between liquid and solid, veins propagate by either channeled porous flow, ductile deformation or fracturing. The main driving forces for upward melt migration appear to be buoyancy and dilatancy; the characteristics of local and regional deformation control the patterns of the granitic vein networks. Partial melting and redistribution of melt and magma from segregation by percolation at the grain scale relayed by pervasive migration through vein networks, is associated with chemical differentiation and generation of new rheological layering of the orogenic crust.</p></div>","PeriodicalId":101024,"journal":{"name":"Physics and Chemistry of the Earth, Part A: Solid Earth and Geodesy","volume":"26 4","pages":"Pages 213-223"},"PeriodicalIF":0.0,"publicationDate":"2001-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1464-1895(01)00048-5","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72283370","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Growth of plutons by floor subsidence : implications for rates of emplacement, intrusion spacing and melt-extraction mechanisms.","authors":"A. Cruden, K. McCaffrey","doi":"10.1016/S1464-1895(01)00060-6","DOIUrl":"https://doi.org/10.1016/S1464-1895(01)00060-6","url":null,"abstract":"","PeriodicalId":101024,"journal":{"name":"Physics and Chemistry of the Earth, Part A: Solid Earth and Geodesy","volume":"82 1","pages":"303-315"},"PeriodicalIF":0.0,"publicationDate":"2001-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77906178","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Transfer of melt between microscopic pores and macroscopic veins in migmatites","authors":"A. Simakin, C. Talbot","doi":"10.1016/S1464-1895(01)00066-7","DOIUrl":"https://doi.org/10.1016/S1464-1895(01)00066-7","url":null,"abstract":"","PeriodicalId":101024,"journal":{"name":"Physics and Chemistry of the Earth, Part A: Solid Earth and Geodesy","volume":"123 22","pages":"363-367"},"PeriodicalIF":0.0,"publicationDate":"2001-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91408195","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Crustal melting in the alborán domain: constraints from xenoliths of the Neogene Volcanic Province","authors":"B. Cesare, M. T. Gomez-Pugnaire","doi":"10.1016/S1464-1895(01)00053-9","DOIUrl":"https://doi.org/10.1016/S1464-1895(01)00053-9","url":null,"abstract":"","PeriodicalId":101024,"journal":{"name":"Physics and Chemistry of the Earth, Part A: Solid Earth and Geodesy","volume":"94 1","pages":"255-260"},"PeriodicalIF":0.0,"publicationDate":"2001-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91535112","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Towards an operational near real-time precipitable water vapor estimation","authors":"J. Douša","doi":"10.1016/S1464-1895(01)00045-X","DOIUrl":"https://doi.org/10.1016/S1464-1895(01)00045-X","url":null,"abstract":"","PeriodicalId":101024,"journal":{"name":"Physics and Chemistry of the Earth, Part A: Solid Earth and Geodesy","volume":"39 1","pages":"189-194"},"PeriodicalIF":0.0,"publicationDate":"2001-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73524810","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Overburden modeling above a compacting reservoir using a trap door apparatus","authors":"E. Papamichos ,&nbsp;I. Vardoulakis ,&nbsp;L.K. Heil","doi":"10.1016/S1464-1895(01)00025-4","DOIUrl":"10.1016/S1464-1895(01)00025-4","url":null,"abstract":"<div><p>The consequences of large reservoir compaction on the surface subsidence and the stress path of the overburden formations were investigated with physical modeling experiments where the compacting reservoir was modeled with a circular retracting trap door (TD) under a deformable overburden of sand. Tests with various overburden heights showed the formation of shear bands starting almost vertically at the TD edges and converging successively to the symmetry axis. A shallow and a deep formation mechanism were identified. In the shallow mechanism, the shear bands reach immediately the upper surface and thus the TD displacement is felt immediately at the surface as subsidence. In the deep mechanism, at low TD displacements the shear bands meet initially each other forming an arch and thus only part of the TD displacement is felt at the surface. At higher TD displacements, additional shear bands form above the initial shear band and eventually reach the surface. After that, the TD displacement is directly felt at the surface as subsidence. The TD stress drops rapidly to a minimum value, which appears to be independent of the overburden height.</p></div>","PeriodicalId":101024,"journal":{"name":"Physics and Chemistry of the Earth, Part A: Solid Earth and Geodesy","volume":"26 1","pages":"Pages 69-74"},"PeriodicalIF":0.0,"publicationDate":"2001-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1464-1895(01)00025-4","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74147236","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The demise of selective availability and implications for the international GPS service","authors":"J.F. Zumberge ,&nbsp;G. Gendt","doi":"10.1016/S1464-1895(01)00113-2","DOIUrl":"10.1016/S1464-1895(01)00113-2","url":null,"abstract":"<div><p>Early on May 2, 2000, selective availability (SA) — the intentional dithering of clocks on GPS satellites — was terminated. The amplitude of variations in transmitter clocks, formerly tens of meters, was reduced by orders of magnitude. These clocks are now much more predictable, with the possibility that the International GPS Service (IGS) can produce, in addition to real-time orbits, real-time <em>clocks</em> that are of significantly higher quality than those in the broadcast ephemeris. Furthermore, the meaning of <em>high</em> in “high rate ground network” to support low-Earth-orbiter (LEO) missions needs to be re-examined.</p></div>","PeriodicalId":101024,"journal":{"name":"Physics and Chemistry of the Earth, Part A: Solid Earth and Geodesy","volume":"26 6","pages":"Pages 637-644"},"PeriodicalIF":0.0,"publicationDate":"2001-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1464-1895(01)00113-2","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87537936","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Boron isotope geochemistry of hydrothermal ore deposits in China: a preliminary study","authors":"S.-Y. Jiang","doi":"10.1016/S1464-1895(01)00132-6","DOIUrl":"10.1016/S1464-1895(01)00132-6","url":null,"abstract":"<div><p>A preliminary boron isotope study of tourmaline was carried out for a number of sediment-hosted massive sulfide deposits and granite-related hydrothermal Sn deposits in China. Tourmalines from the Yindongzi-Tongmugou (Devonian) and the Qingchengzi (Proterozoic) Pb-Zn deposits show δ¹¹B values of −7.6 to −13.7‰, which are within the typical δ¹¹B ranges of massive sulfide deposits worldwide. At Dachang Sn-polymetallic deposit, the hydrothermal fluids responsible for the formation of banded tourmalinites have remarkable different δ¹¹B values (−1 to −5‰) from those of quartz-tourmaline veins near the granite contacts (∼ −10‰), which indicate their different origins. Together with other geological and geochemical evidence, the banded tourmalinites at Dachang are of submarine hydrothermal exhalative origin. Overall, the boron isotopic compositions of tourmaline from massive sulfide deposits are mainly controlled by source rock compositions, and non-marine evaporites may have played an important role in the massive sulfide ore formation in same cases. Other controlling factors include temperatures, water/rock ratios, and seawater entrainments.</p><p>Tourmalines from the granite-related Yidong Sn deposit display a gradual increase in δ¹¹B value from within the granite (−13.9‰), to the contact (−12.7 to −11.9‰) and the country rocks (−11.4 to −11.3‰). It is suggested that these variations reflect the boron isotope fractionation during magmatic degassing and magmatic-hydrothermal ore-forming processes with ¹¹B preferentially partitioned into hydrothermal solutions. The similar and limited δ¹¹B variations (−19.5 to −13.9‰) in granitic tourmalines from the granite-related Sn deposits in South China suggest that these Sn-rich granites may have similar source rocks from the basement of metasedimentary rocks and volcanic rocks in this region.</p></div>","PeriodicalId":101024,"journal":{"name":"Physics and Chemistry of the Earth, Part A: Solid Earth and Geodesy","volume":"26 9","pages":"Pages 851-858"},"PeriodicalIF":0.0,"publicationDate":"2001-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1464-1895(01)00132-6","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88558066","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}