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1

Scherstén, Anders, Henrik Stendal, and Tomas Næraa. "Geochemistry of greenstones in the Tasiusarsuaq terrane, southern West Greenland." Geological Survey of Denmark and Greenland (GEUS) Bulletin 15 (July 10, 2008): 69–72. http://dx.doi.org/10.34194/geusb.v15.5047.

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Tonalite-trondhjemite–granodiorite (TTG) gneisses and mela nocratic to ultramafic greenstones dominate the Arc haean basement of southern West Greenland. The greenstones are likely to represent different original environments, which is important as the mineral deposits they may host depend on this. For example, massive sulphide deposits associated with gold and base metals are commonly volcan og enic, while chrome, nickel and platinum group elements are more commonly associated with layered intrusions (Robb 2005). Cur rent investigations by the Geological Survey of Denmark and Greenland (GEUS) in southern West Greenl and are therefore focused on the origin of greenstones and their relationship to associated TTG gneisses. Here, we report on work in progress on greenstones within the Tasiusarsuaq terrane (Fig. 1; Friend et al. 1996). They differ from many other greenstone belts in southern West Green land in their spatial association with the TTG gneisses. Unlike the Isua, Ivisârtoq and Storø greenstone belts in the central and northern Nuuk region, the Tasiusarsuaq greenstones are not proximal to terrane boundaries but form dismembered blocks and slivers within the terrane (Fig. 1). Contact relationships to the gneisses are almost exclusively tectonic, and primary textures are, with rare exceptions, ob literated by amphibolite to granulite facies metamorphism.
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Rakovan, John. "Greenstone." Rocks & Minerals 83, no. 6 (November 2008): 553–56. http://dx.doi.org/10.3200/rmin.83.6.553-556.

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3

Phillips, G. Neil, David I. Groves, and Isobel J. Brown. "Source requirements for the Golden Mile, Kalgoorlie: significance to the metamorphic replacement model for Archean gold deposits." Canadian Journal of Earth Sciences 24, no. 8 (August 1, 1987): 1643–51. http://dx.doi.org/10.1139/e87-158.

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The Golden Mile at Kalgoorlie represents a giant Archean hydrothermal gold system localized by ductile shear zones and hosted mainly by a differentiated tholeiitic sill. Chlorite, carbonate, and pyrite alteration zones cover the whole mineralized area (1 km × 3 km), and calculations suggest that for the Golden Mile (production around 1200 t Au), the amounts of components added to these alteration zones are 340 Mt CO2, 20 Mt K, and 5 Mt S. If one adopts a metamorphic-replacement model for gold mineralization in which all ore components derive from devolatilization of greenstones at amphibolite facies or above, these data suggest that a source area involving a 5 km thick greenstone slab of area 8 km × 8 km could produce the necessary CO2, K, S, H2O, and Au. This is considered a reasonable volume of greenstone belt, and under such a model the minimum spacing of large gold deposits would be approximately 20 km along strike.Neither special Au-enriched source rocks nor unreasonably large volumes of greenstone belt are required to produce a giant gold deposit. Instead, the most critical parameters are suitable structural environments providing focussing of fluids and multiple channelways through specific Fe-rich, low-tensile-strength host rocks to ensure efficient depositional mechanisms.
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Hofmann, A., H. Xie, L. Saha, and C. Reinke. "Granitoids and greenstones of the White Mfolozi Inlier, south-east Kaapvaal Craton." South African Journal of Geology 123, no. 3 (September 1, 2020): 263–76. http://dx.doi.org/10.25131/sajg.123.0019.

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Abstract A Palaeoarchaean greenstone fragment and associated granitoid gneisses from an area south of Ulundi in KwaZulu-Natal is described. The fragment consists of an association of garnetiferous amphibolite and calc-silicate that was intruded at 3388 ± 4 Ma by tonalite and at 3275 ± 4 Ma by trondhjemite. Strong ductile deformation of the greenstones and granitoids under amphibolite facies conditions (7 kbar and 600 to 650°C) took place prior to uplift and emplacement of a granite batholith at ~3.25 Ga ago in which the granitoid gneiss-greenstone domain is now found. Magmatism 3.27 to 3.25 Ga ago was a direct response to regional metamorphism and anataxis, and gave rise to stabilization of the southeastern Kaapvaal Craton at that time, earlier than other parts of the craton. Deposition of quartz-arenites on stable granitic basement took place <3.1 Ga ago. Contrasting ages in magmatic pulses and regional metamorphism reflect a different crustal growth history of the eastern and southeastern part of the Kaapvaal Craton.
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Abbott, D. "Greenstone belts." Eos, Transactions American Geophysical Union 79, no. 10 (1998): 123. http://dx.doi.org/10.1029/98eo00089.

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6

Falkenström, Per. "Greenstone Dimensions." Lithic Technology 36, no. 2 (September 2011): 141–52. http://dx.doi.org/10.1179/lit.2011.36.2.141.

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7

Thurston, Phillips C. "Igneous Rock Associations 19. Greenstone Belts and Granite−Greenstone Terranes: Constraints on the Nature of the Archean World." Geoscience Canada 42, no. 4 (December 7, 2015): 437. http://dx.doi.org/10.12789/geocanj.2015.42.081.

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Greenstone belts are long, curvilinear accumulations of mainly volcanic rocks within Archean granite−greenstone terranes, and are subdivided into two geochemical types: komatiite−tholeiite sequences and bimodal sequences. In rare instances where basement is preserved, the basement is unconformably overlain by platform to rift sequences consisting of quartzite, carbonate, komatiite and/or tholeiite. The komatiite−tholeiite sequences consist of km-scale thicknesses of tholeiites, minor intercalated komatiites, and smaller volumes of felsic volcanic rocks. The bimodal sequences consist of basal tholeiitic flows succeeded upward by lesser volumes of felsic volcanic rocks. The two geochemical types are unconformably overlain by successor basin sequences containing alluvial–fluvial clastic metasedimentary rocks and associated calc-alkaline to alkaline volcanic rocks. Stratigraphically controlled geochemical sampling in the bimodal sequences has shown the presence of Fe-enrichment cycles in the tholeiites, as well as monotonous thicknesses of tholeiitic flows having nearly constant MgO, which is explained by fractionation and replenishment of the magma chamber with fresh mantle-derived material. Geochemical studies reveal the presence of boninites associated with the komatiites, in part a result of alteration or contamination of the komatiites. Within the bimodal sequences there are rare occurrences of adakites, Nb-enriched basalts and magnesian andesites. The greenstone belts are engulfed by granitoid batholiths ranging from soda-rich tonalite−trondhjemite−granodiorite to later, more potassic granitoid rocks. Archean greenstone belts exhibit a unique structural style not found in younger orogens, consisting of alternating granitoid-cored domes and volcanic-dominated keels. The synclinal keels are cut by major transcurrent shear zones. Metamorphic patterns indicate that low pressure metamorphism of the greenstones is centred on the granitoid batholiths, suggesting a central role for the granitoid rocks in metamorphosing the greenstones. Metamorphic patterns also show that the proportion of greenstones in granite−greenstone terranes diminishes with deeper levels of exposure. Evidence is presented on both sides of the intense controversy as to whether greenstone belts are the product of modern plate tectonic processes complete with subduction, or else the product of other, lateral tectonic processes driven by the ‘mantle wind.’ Given that numerous indicators of plate tectonic processes – structural style, rock types, and geochemical features − are unique to the Archean, it is concluded that the evidence is marginally in favour of non-actualistic tectonic processes in Archean granite−greenstone terranes.RÉSUMÉLes ceintures de roches vertes sont des accumulations longiformes et curvilinéaires, principalement composées de roches volcaniques au sein de terranes granitique archéennes, et étant subdivisées en deux types géochimiques: des séquences à komatiite–tholéite et des séquences bimodales. En de rares occasions, lorsque le socle est préservé, ce dernier est recouvert en discordance par des séquences de plateforme ou de rift, constituées de quartzite, carbonate, komatiite et/ou de tholéiite. Les séquences de komatiite-tholéiite forment des épaisseurs kilométriques de tholéiite, des horizons mineurs de komatiites, et des volumes de moindre importance de roches volcaniques felsiques. Les séquences bimodales sont constituées à la base, de coulées tholéiitiques surmontées par des volumes mineurs de roches volcaniques felsiques. Ces deux types géochimiques sont recouverts en discordance par des séquences de bassins en succession contenant des roches métasédimentaires clastiques fluvio-alluvionnaires associées à des roches volcaniques calco-alcalines à alcalines. Un échantillonnage à contrôle stratigraphique des séquences bimodales a révélé la présence de cycles d’enrichissement en Fe dans les tholéiites, ainsi que des épaisseurs continues d’épanchements tholéiitiques ayant des valeurs presque constante en MgO, qui s’explique par la cristallisation fractionnée et le réapprovisionnement de la chambre magmatique par du matériel mantélique. Les études géochimiques montrent la présence de boninites associées aux komatiites, résultant en partie de l’altération ou de la contamination des komatiites. Au sein des séquences bimodales, on retrouve en de rares occasions des adakites, des basaltes enrichis en Nb et des andésites magnésiennes. Les ceintures de roches vertes sont englouties dans des batholites granitoïdes de composition passant des tonalites−trondhjémites−granodiorites enrichies en sodium, à des roches granitoïdes tardives plus potassiques. Les ceintures de roches vertes archéennes montrent un style structural unique que l’on ne retrouve pas dans des orogènes plus jeunes, et qui est constitué d’alternances de dômes à cœur granitoïdes et d`affaissements principalement composés de roches volcaniques. Les synclinaux formant les affaissements sont recoupés par de grandes zones de cisaillement. Les profils métamorphiques indiquent que le métamorphisme de basse pression des roches vertes est centré sur les batholites, indiquant un rôle central des roches granitoïdes durant le métamorphisme des roches vertes. Les profils métamorphiques montrent également que la proportion de roches vertes dans les terranes granitiques diminue avec l’exposition des niveaux plus profonds. On présente les arguments des deux côtés de l’intense controverse voulant que les ceintures de roches vertes soient le produit de processus moderne de la tectonique des plaques incluant la subduction, ou alors le produit d’autres processus tectoniques découlant du « flux mantélique ». Étant donné la présence des indicateurs des processus de tectonique des plaques – style structural, les types de roches, et les caractéristiques géochimiques – ne se retrouvent qu’à l’Archéen, nous concluons que les indices favorisent légèrement l’option de processus tectoniques non-actuels dans les terranes granitiques de roches vertes à l’Archéen.
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8

Anhaeusser, C. R. "The geology and tectonic evolution of the northwest part of the Barberton Greenstone Belt, South Africa: A review." South African Journal of Geology 122, no. 4 (December 1, 2019): 421–54. http://dx.doi.org/10.25131/sajg.122.0033.

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AbstractFormations on the northwestern flank of the Barberton Greenstone Belt have hosted over 85% of all the gold recovered from the ca. 3550 to 3000 Ma Barberton Supergroup since early discoveries in 1872. This sector of the greenstone belt also happens to coincide with a complex tectonic architecture resulting from successive stages of folding and faulting superimposed onto a complex lithostratigraphy. Of particular importance has been the influence of two diapiric granitoid intrusions that caused added structural complexity following their emplacement ca. 3227 to 3250 Ma. Of these the larger Kaap Valley Pluton invaded the area north of present day Barberton town causing the separation of the greenstones into a northern arm (Jamestown Schist Belt) and a southern sector which remained attached to the main greenstone belt (Moodies Hills). The ballooning pluton produced vertical as well as horizontal flattening stresses, the latter reactivating earlier high-angle faults and resulting in subhorizontal strike-slip movements, particularly along the Barbrook Fault Zone, which acted as a right-lateral strike-slip fault. Formations north of this fault were buckled, following progressive deformation in the region known as the Sheba Hills, into major synclinal folds (Eureka and Ulundi Synclines) with folded axial planes that dip steeply to the south, southeast or east. The second granitoid intrusion (Stentor Pluton), which has been extensively modified by subsequent magmatic events, caused significant flattening of greenstone belt rocks in the northeastern part of the Barberton Greenstone Belt (Three Sisters region) as well as in other areas rimming the granitic body. Combined, the two plutons produced a wide range of interference and reactivated structures particularly affecting a triangular region extending from the Jamestown Schist Belt into the area occupied by the New Consort Gold Mine and areas to the east. This paper attempts to outline, in the simplest manner, the geological and structural evolution of the main gold-producing region of the Barberton Goldfield. The principal aim is therefore to highlight the structural influence of the diapiric plutonism and the manner in which the plutons contributed significantly to the horizontal reactivation of pre-existing regional faults, which in turn, resulted in the progressive deformation of a heterogeneous lithological terrane.
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9

St. Seymour, Karen, Andrew Turek, Ronald Doig, Stephen Kumarapeli, and Robert Fogal. "First U–Pb zircon ages of granitoid plutons from the La Grande greenstone belt, James Bay area, New Quebec." Canadian Journal of Earth Sciences 26, no. 5 (May 1, 1989): 1068–73. http://dx.doi.org/10.1139/e89-088.

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Zircon ages from three granitoid plutons are the first to be reported from the La Grande greenstone belt. Two of the dated samples are from highly tectonized, early tectonic plutons that at the present level of erosion are just outside the greenstone belt proper. Their zircon ages of ca. 2740 Ma are emplacement ages or alternatively represent the age of maximum deformation of the greenstone belt. The third sample is from a mildly deformed late tectonic pluton within the greenstone belt. Its zircon age of ca. 2670 Ma probably represents the emplacement age. The above dates and the relationships of the dated plutons to the greenstone belt as a whole suggest that the bulk of the volcanism in the La Grande belt is older than 2.7 Ga. This limiting age indicates that the age of the La Grande "supracrustals" is similar to those of the other greenstone belts in the Superior Province.
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10

Silberman, Bernard S. "J. David Greenstone." PS: Political Science & Politics 23, no. 03 (September 1990): 476–77. http://dx.doi.org/10.1017/s1049096500033400.

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11

Diener, J. F. A., and A. Dziggel. "Can mineral equilibrium modelling provide additional details on metamorphism of the Barberton garnet amphibolites?" South African Journal of Geology 124, no. 1 (March 1, 2021): 211–24. http://dx.doi.org/10.25131/sajg.124.0003.

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Abstract The Stolzburg domain to the south of the Barberton Greenstone Belt preserves evidence for a 3.23 Ga subduction–collision tectonic event. Garnet amphibolite greenstone remnants have previously yielded conventional thermobarometric P-T estimates of 12 to 15 kbar at 600 to 650°C, 8 to 11 kbar at 650 to 700°C and 7.5 to 8.5 kbar at 560 to 640°C from, respectively, the Inyoni shear zone along the western margin of the Stolzburg domain, the central part of the domain and from the Tjakastad schist belt on the boundary with the main body of the Barberton Greenstone Belt. Pseudosection calculations constrain the stability conditions of the peak metamorphic assemblages at the three localities to be 10 kbar at 675 to 690°C, ~10 kbar at 700°C and ~7 and 10 kbar at 660°C respectively. Although it is possible that the peak metamorphic assemblages may be displaced to somewhat lower conditions if Mn is considered in the calculations, these estimates are generally in good agreement with existing estimates, and confirm that the Stolzburg domain exposes an intact mid- to lower-crustal section that was metamorphosed in a relatively cool environment at 3.23 Ga. Our results do not support previously documented higher-pressure conditions, and we contend that the mineral assemblages used to derive these estimates can equally reflect the conditions determined here. The presence of albite-epidote inclusion assemblages in garnet indicates that the likely prograde path involved a component of heating at depth, which is typical of subduction–collision environments and markedly different from the heating–burial paths expected for sinking greenstones in a vertical tectonic model.
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12

Kozlov, N. E., N. O. Sorokhtin, N. E. Kozlova, and Eu V. Martynov. "Geological structure of the Ustoyarvi region (North-Western part of the Russian Arctic)." Vestnik MGTU 25, no. 1 (March 31, 2022): 12–26. http://dx.doi.org/10.21443/1560-9278-2022-25-1-12-26.

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The paper presents data on geology and composition of rocks from the Ustoyarvi region (the North-Western Arctic zone of Russian Federation). Their compositional analysis (including mathematical evaluation of the similarity/difference measure) provided much reliable conclusion that the rocks from this area, which are presumably attributed to the Ustoyarvi structure (Ustoyarvinsky Greenstone Belt) were similar to those from the Ura-Guba area in the Kolmozero-Voronya Belt and continued it. In addition, it has been shown that from west to east lithotectonic units in the adjacent (Suormussky) Block become gradually impregnated with tectonic wedges of rocks of the Ustoyarvi Greenstone Belt. It indicates increasing collisional interaction between rock associations with a varied genesis. P-T formation parameters have been specified for komatiites from greenstone belts, i. e. the Kolmozero-Voronya, Ura-Guba, Ustoyarvi and Western Litsa area. It has been defined that komatiites of the Ustoyarvi Greenstone Belt were formed under pressure of about 5 hPa, komatiites of the Ura-Guba area - about 4.5 hPa, komatiites of the Kolmozero-Voronya - about 2 hPa. Thus, komatiites of the Ustoyarvi Greenstone Belt are more high-pressure formations.
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Jaime-Riverón, Olaf. "OLMEC GREENSTONE IN EARLY FORMATIVE MESOAMERICA: EXCHANGE AND PROCESS OF PRODUCTION." Ancient Mesoamerica 21, no. 1 (2010): 123–33. http://dx.doi.org/10.1017/s095653611000009x.

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AbstractThe earliest uses of Olmec greenstone (jadeite, greenstone, schist, green quartz, and others) accelerated the interregional exchange of technology and raw materials. These relationships provoked asymmetry between polities of different parts of Mesoamerica and within Olmec sites. There were stronger relationships between the Gulf Coast and Chiapas. In general terms, greenstone artifacts display an evolutionary process similar to ceramics and basalt sculpture in the emergence of complex society during terminal Early Formative times. This paper focuses on the exchange of technological choices and asymmetry between Gulf Coast of Mexico and the rest of Mesoamerica.
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Jirsa, Mark A. "The Midway sequence: a Timiskaming-type, pull-apart basin deposit in the western Wawa subprovince, Minnesota." Canadian Journal of Earth Sciences 37, no. 1 (April 1, 2000): 1–15. http://dx.doi.org/10.1139/e99-111.

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The Midway sequence is an assemblage of subaerially deposited clastic and volcanic rocks that forms a narrow wedge within Neoarchean greenstone of the western Wawa subprovince of the Superior Province. Volcanic conglomerate in the Midway sequence contains clasts of stratigraphically older greenstone, together with clasts of a distinctive hornblende-phyric trachyandesite that is not represented among the older greenstone flows. The trachyandesite forms flows and pyroclastic units that are interbedded with lenticular deposits of volcanic conglomerate in a manner interpreted to indicate approximately coeval volcanism and alluvial fan - fluvial sedimentation within a linear, restricted, and tectonically active depocentre. The Midway sequence unconformably overlies greenstone on one side and is bounded by a regional-scale, strike-slip fault on the other. Structural analyses show that the Midway sequence was deposited after an early, precleavage folding event (D1) in greenstone, but before the regional metamorphic cleavage-forming D2 deformation. Lithologic and structural attributes are consistent with deposition in a strike-slip "pull-apart" basin. The stratigraphic and structural characteristics of the Midway sequence are generally similar to those of the Timiskaming Group and Timiskaming-type rocks in Canada, and more specifically to those of the Shebandowan Group in the Thunder Bay district. This similarity implies that the latest Archean tectonic and magmatic history of the western Wawa subprovince may have been nearly synchronous over great distances.
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Pamungkas, Faisal Dinar, and Agus Purnomo Sidi. "The Influence of Leadership Style and Discipline on Employee Performance at PT. Notojoyo Nusantara Malang." International Journal of Science, Technology & Management 3, no. 1 (January 9, 2022): 50–55. http://dx.doi.org/10.46729/ijstm.v3i1.423.

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This study aims to determine how the influence of leadership style and discipline on employee performance at PT. Notojoyo Nusantara in a case study of the construction of the Greenstone City Malang housing area. This study used a research instrument, namely a questionnaire to obtain primary data. The population in this study were all employees of Greenstone City with the determination of the sample using the saturated sample technique with the stratified random sampling method. Respondents in this study were 44 employees. Analysis of the data in this study using multiple linear regression analysis where it is known that leadership style and discipline have no significant positive effect on the performance of Greenstone City employees.
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16

Kusky, Timothy M., and Pamela A. Winsky. "Structural relationships along a greenstone/shallow water shelf contact, Belingwe greenstone belt, Zimbabwe." Tectonics 14, no. 2 (April 1995): 448–71. http://dx.doi.org/10.1029/94tc03086.

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17

Vrevskii, A. B. "Non-subduction petrological mechanisms for the growth of the neoarcheam continental crust of the Kola–Norwegian terrane, Fennoscandian shield: geological and isotope-geochemical evidence." Петрология 27, no. 2 (April 2, 2019): 161–86. http://dx.doi.org/10.31857/s0869-59032161-186.

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The paper reports new data on the composition and age of the Neoarchean calc-alkaline volcanic rocks of the Uraguba–Kolmozero–Voron’ya greenstone belt (UKV GB). Petrological-geochemical modeling indicates a polygenetic origin of primary melts of the basalt–andesite–dacite association and non-subduction geodynamic mechanisms for the crustal growth in the largest greenstone belt of the Kola–Norwegian Block of the Fennoscandian shield.
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Baofeng, Shen, Peng Xiaoliang, Luo Hui, and Mao Debao. "Archaean Greenstone Belts in China." Acta Geologica Sinica - English Edition 7, no. 1 (May 29, 2009): 15–29. http://dx.doi.org/10.1111/j.1755-6724.1994.mp7001002.x.

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Shackleton, R. M. "Tectonic evolution of greenstone belts." Geological Society, London, Special Publications 95, no. 1 (1995): 53–65. http://dx.doi.org/10.1144/gsl.sp.1995.095.01.04.

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20

Witten, Ian H., David Bainbridge, and Stefan Boddie. "Greenstone: Open-source DL software." Communications of the ACM 44, no. 5 (May 2001): 47. http://dx.doi.org/10.1145/374308.374338.

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Fushimi, Marcela, Mariana Pichinini, Ana María Sanllorenti, and Martín Williman. "Greenstone: uso actual en Argentina." RDBCI: Revista Digital de Biblioteconomia e Ciência da Informação 16, no. 2 (April 23, 2018): 306–28. http://dx.doi.org/10.20396/rdbci.v16i2.8651806.

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Este artigo apresenta as características e a história do software para criar e gerenciar bibliotecas digitais Greenstone, desenvolvidas inicialmente pela Universidade de Waikato, Nova Zelândia, em 1997. Primeiro, a comunidade de usuários é descrita a nível global, com foco no uso atual que o software conseguiu na Argentina: o número de implementações disponíveis, sua evolução, o tipo, tamanho e variedade dos desenvolvimentos existentes, bem como a sua aplicação à gestão de repositórios digitais de ciência e tecnologia no campo das instituições científicas, tecnológicas e de ensino superior na Argentina. Em segundo lugar, são detalhadas as ações realizadas após a criação do Centro Nacional para a Promoção da Greenstone na Argentina em 2009. Os dados coletados das pesquisas permitiram observar que os motivos predominantes para a escolha desta plataforma foram, entre outros, a facilidade de instalação e configuração, seu baixo nível de requisitos tecnológicos, a escassez geral de recursos humanos dedicados a essa atividade e a complexidade do software alternativo existente naquele momento. Ao longo destes 8 anos, tanto os repositórios digitais quanto os sistemas que os suportam evoluíram drasticamente, modificando o cenário atual. Paralelamente, em 2016, a nova versão principal da Greenstone implementou uma reengenharia completa do software para adaptá-la às tecnologias em uso: XML, XSLT, serviços Web e Java. Como conseqüência disso, a comunidade de desenvolvimento local apresenta novos desafios para a migração de bibliotecas digitais e repositórios implementados com versões anteriores.
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Lodge, Robert W. D., Harold L. Gibson, Greg M. Stott, James M. Franklin, and George J. Hudak. "Geodynamic setting, crustal architecture, and VMS metallogeny of ca. 2720 Ma greenstone belt assemblages of the northern Wawa subprovince, Superior Province." Canadian Journal of Earth Sciences 52, no. 3 (March 2015): 196–214. http://dx.doi.org/10.1139/cjes-2014-0163.

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The greenstone belts along the northern margin of the Wawa subprovince of the Superior Province (Vermilion, Shebandowan, Winston Lake, Manitouwadge) formed at ca. 2720 Ma and have been interpreted to be representative of a rifted-arc to back-arc tectonic setting. Despite a common inferred tectonic setting and broad similarities, these greenstone belts have a significantly different metallogeny as evidenced by different endowments in volcanogenic massive sulphide (VMS), magmatic sulphide, and orogenic gold deposits. In this paper, we examine differences in geodynamic setting and crustal architecture as they pertain to the metallogeny of each greenstone belt by characterizing the regional-scale trace-element and isotopic (Nd and Pb) geochemistry of each belt. The trace-element geochemistry of the Vermilion greenstone belt (VGB) shows evidence for a transition from arc-like to back-arc mafic rocks in the Soudan belt to plume-driven rifted arcs in the ultramafic-bearing Newton belt. The Shebandowan greenstone belt (SGB) has a significant proportion of calc-alkalic, arc-like basalts, intermediate lithofacies, and high-Mg andesites, which are characteristic of low-angle, “hot” subduction. Extensional settings within the SGB are plume-driven and associated with komatiitic ultramafic and mid-ocean ridge basalt (MORB)-like basalts. The Winston Lake greenstone belt (WGB) is characterized by a transition from calc-alkalic, arc-like basalts to back-arc basalts upward in the strata and is capped by alkalic ocean-island basalt (OIB)-like basalts. This association is consistent with plume-driven rifting of a mature arc setting. Each of the VGB, SGB, and WGB show some isotopic evidence for the interaction with a juvenile or slightly older differentiated crust. The Manitouwadge greenstone belt (MGB) is characterized by isotopically juvenile, bimodal, tholeiitic to transitional volcanic lithofacies in a back-arc setting. The MGB is the most isotopically juvenile belt and is also the most productive in terms of VMS mineralization. The Zn-rich VMS mineralization within the WGB suggests a relatively lower-temperature hydrothermal system, possibly within a relatively shallow-water environment. The Zn-dominated and locally Au-enriched VMS mineralization, as well as mafic lithofacies and alteration assemblages, are characteristic of relatively shallower-water deposition in the VGB and SGB, and indicate that the ideal VMS-forming tectonic condition may have been compromised by a shallower-water depositional setting. However, the thickened arc crust and compressional tectonics of the SGB suprasubduction zone during hot subduction may have provided a crustal setting more favourable for the magmatic Ni–Cu sulphide and relative gold endowment of this belt.
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Pan, Yuanming, and Michael E. Fleet. "Polymetamorphism in the Archean Hemlo – Heron Bay greenstone belt, Superior Province: P–T variations and implications for tectonic evolution." Canadian Journal of Earth Sciences 30, no. 5 (May 1, 1993): 985–96. http://dx.doi.org/10.1139/e93-082.

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The tectono-metamorphic history of the late Archean (2800–2600 Ma) Hemlo – Heron Bay greenstone belt in the Superior Province has been delineated from textural relationships, mineral chemistry, and P–T paths in metapelites, cordierite–orthoamphibole rocks, and metabasites from the White River exploration property, Hemlo area, Ontario. An early low-temperature, medium-pressure metamorphism (about 500 °C and 6–6.5 kbar (1 kbar = 100 MPa)) is indicated by the occurrence of relict kyanite and staurolite porphyroblasts and zoned garnet porphyroblasts in metapelites and the presence of zoned calcic amphiboles in metabasites. This early metamorphism appears to have been coeval with the previously documented D1 deformation that is associated with, for example, low-angle thrusts. A second regional metamorphism predominates in the Hemlo – Heron Bay greenstone belt and is generally of relatively low grade, at about 510–530 °C and 3.2–3.5 kbar, over most of the study area and increases to medium grade (550–650 °C and 4–5 kbar) towards the southern margin with the Pukaskwa Gneissic Complex and along the central axis enclosing the Hemlo Shear Zone. The second regional metamorphism was contemporaneous with the D3 deformation and was probably related to plutonism. This type of polymetamorphism in the Hemlo – Heron Bay greenstone belt may be equivalent to those in Phanerozoic subduction complexes and therefore supports the arc–arc accretion model for the development of the southern Superior Province. Although the Hemlo – Heron Bay greenstone belt most likely represents a single tectonic environment (an oceanic island arc), the restricted occurrence of the relict kyanite and staurolite indicates that the central portion of this Archean greenstone belt probably was at a deeper crustal level at the time of the first metamorphic event.
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24

Hofmann, A., C. R. Anhaeusser, and X.-H. Li. "Layered ultramafic complexes of the Barberton Greenstone Belt – age constraints and tectonic implications." South African Journal of Geology 124, no. 1 (March 1, 2021): 7–16. http://dx.doi.org/10.25131/sajg.124.0002.

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Abstract Layered ultramafic–mafic complexes are a common component of the stratigraphically uppermost part of the Onverwacht Group of the Barberton Greenstone Belt. Associated with the Mendon Formation in the south and the Weltevreden Formation in the north, they represent an assemblage of thick differentiated flows and shallow synvolcanic intrusions ranging in composition from dunite to gabbro. U-Pb zircon dating of gabbro from the Sawmill and the Mundt’s Concession ultramafic complexes from the northern part of the Barberton Greenstone Belt yielded ages of 3 258 ± 8 Ma and 3 244 ± 11 Ma, respectively. The ultramafic complexes are thus regarded to have been emplaced during a magmatic flare-up in the final stage of Weltevreden Formation volcanism, post-dating ultramafic magmatism in the southern part of the belt by several millions of years and thus suggesting diachronous evolution of the Onverwacht Group in the Barberton Greenstone Belt.
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Van Kranendonk, Martin J. "Cool greenstone drips and the role of partial convective overturn in Barberton greenstone belt evolution." Journal of African Earth Sciences 60, no. 5 (July 2011): 346–52. http://dx.doi.org/10.1016/j.jafrearsci.2011.03.012.

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26

Hollis, Julie A., Jeroen A. M. Van Gool, Agnete Steenfelt, and Adam A. Garde. "Greenstone belts in the central Godthåbsfjord region, southern West Greenland." Geological Survey of Denmark and Greenland (GEUS) Bulletin 7 (July 29, 2005): 65–68. http://dx.doi.org/10.34194/geusb.v7.4843.

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In 2004 the Geological Survey of Denmark and Greenland (GEUS) initiated a study of the origin and tectono-metamorphic evolution of greenstone belts and important regional structures in the central Godthåbsfjord region, southern West Greenland (Fig. 1; Hollis et al. 2004). Like other Archaean belts worldwide, these greenstone belts are locally host to gold mineralisation. Their complexity requires a combination of detailed geological mapping, geochemistry, petrographic work and geochronological studies to develop models of their geological setting, evolution and gold mineralisation.
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27

Kioe-A-Sen, Nicole M. E., Manfred J. van Bergen, Theo E. Wong, and Salomon B. Kroonenberg. "Gold deposits of Suriname: geological context, production and economic significance." Netherlands Journal of Geosciences - Geologie en Mijnbouw 95, no. 4 (November 3, 2016): 429–45. http://dx.doi.org/10.1017/njg.2016.40.

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AbstractGold has been a major economic asset for Suriname for more than a century. The long history of gold mining, concentrated in large parts of a greenstone belt in the northeast of the country, began with small-scale artisanal extraction activities and has recently seen the development of major open-pit operations. Despite the range of mining activities, Suriname's gold deposits and occurrences are under-explored from a scientific point of view. Primary gold mineralisations in the greenstone belt occur in multiple forms, and although their origin is commonly related to the Palaeoproterozoic Trans-Amazonian orogeny, the controls of ore formation in specific cases often remain obscure. This contribution presents an abridged overview of currently available information on the geological setting and characteristics for some of the main deposits where gold is extracted. In view of the consistent link between gold metallogeny and granitoid–greenstone belts in the northern Guiana Shield, the mineralised settings in Suriname are discussed in a regional context.
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28

Schwerdtner, W. M. "Preliminary estimates of the amount of continuous horizontal shortening across an Archean greenstone belt." Canadian Journal of Earth Sciences 22, no. 4 (April 1, 1985): 506–13. http://dx.doi.org/10.1139/e85-052.

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Simple two-dimensional techniques are used to make an estimate of the total shortening across a narrow greenstone belt in northwestern Ontario. The techniques are based on the basic principle of restoring the predeformational geometry of a horizontal traverse across the belt. Depending on the technique used this traverse is a string of line elements or a chain of finite elements. The strain ratios available for the restoration are minimal values and need to be increased significantly to obtain realistic results. Depending on the strain values selected for the restoration, amounts of horizontal shortening range from 17 to 49%. The actual amount remains unknown, but is thought to be < 50%.In view of the apparent variation in longitudinal strain along the greenstone belt, a three-dimensional treatment seems to be necessary. This would require that strain measurements be taken systematically throughout, rather than along a single traverse across, a greenstone belt segment.
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29

Parichi, Ramesh, and Faizul Nisha. "Greenstone Digital Library Management System – a functional review based on selected criteria." Library Hi Tech News 32, no. 10 (December 7, 2015): 16–21. http://dx.doi.org/10.1108/lhtn-06-2015-0041.

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Purpose – This paper aims to provide a functional review of Greenstone based on selected criteria, viz., user friendliness, administration, customization, international metadata standards and interoperability, search and browse capabilities, security aspects, statistical reports, unique features and limitations. Design/methodology/approach – The paper is solely based on secondary information collected from different sources like books, articles from national and international journal articles, reports of various organizations and local newspapers as well as the resources available in various websites. Findings – It was observed that the Greenstone on Windows is less robust than the other operating systems such as Linux. It was reported that during the collection building process of some documents, the system hangs and the user has to turn off the browsers and the interfaces, and no alternate method is available to restore normalcy. The software has been reviewed on selected criteria, and it is suggested to use Greenstone Digital Library Management System (DLMS) system as the most suitable and convenient for installation, uploading of documents and usage for small- and medium-type organizations. Practical implications – This paper would be of great help for library professionals to learn about diverse features available in the software and in selecting the best DLMS. Originality/value – The Greenstone DLMS is functionally reviewed and analysed based on selected broad criteria, viz., user friendliness, administration, customization, international metadata standards and interoperability, search and browse capabilities, security aspects and statistical functions.
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30

Altman, Micah. "Open Source Software for Libraries: from Greenstone to the Virtual Data Center and Beyond." IASSIST Quarterly 25, no. 4 (December 4, 2002): 5. http://dx.doi.org/10.29173/iq856.

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31

TOMAZZOLI, EDISON R. "O GREENSTONE BELTDE GOIÁS: ESTUDOS GEOCRONOLÓGICOS." Revista Brasileira de Geociências 22, no. 1 (March 1, 1992): 56–60. http://dx.doi.org/10.25249/0375-7536.19925660.

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32

Biró, Katalin T., György Szakmány, Veronika Szilágyi, Zoltàn Kovàcs, Zsolt Kasztovszky, and Ildikó Harsányi. "The first greenstone axe in Hungary." Materiale şi cercetãri arheologice (Serie nouã) 1, no. 1 (2021): 517–27. http://dx.doi.org/10.3406/mcarh.2021.2227.

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33

Henry, D. A., and W. D. Birch. "Cambrian greenstone on Phillip Island, Victoria." Australian Journal of Earth Sciences 39, no. 5 (December 1992): 567–75. http://dx.doi.org/10.1080/08120099208728050.

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34

Belyaev, E. V. "Apatite-bearing greenstone belts in Russia." Russian Geology and Geophysics 51, no. 8 (August 2010): 857–62. http://dx.doi.org/10.1016/j.rgg.2010.07.007.

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35

Witten, Ian H., and David Bainbridge. "Creating digital library collections with Greenstone." Library Hi Tech 23, no. 4 (December 2005): 541–60. http://dx.doi.org/10.1108/07378830510636337.

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36

Bethune, K. M., and R. J. Scammell. "Geology, geochronology, and geochemistry of Archean rocks in the Eqe Bay area, north-central Baffin Island, Canada: constraints on the depositional and tectonic history of the Mary River Group of northeastern Rae Province." Canadian Journal of Earth Sciences 40, no. 8 (August 1, 2003): 1137–67. http://dx.doi.org/10.1139/e03-028.

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Results of stratigraphic, U–Pb geochronological, and geochemical study are reported for rocks in a 2800 km2 area along the southeastern margin of the Archean Rae Province on north-central Baffin Island. Archean rocks include a gneiss complex, two greenstone belts of the Mary River Group, and various younger plutonic rocks. The 3000–2800 Ma gneiss complex contains intrusions of orthogneiss, dated at 2780–2770 Ma. Intermediate-felsic volcanism in overlying greenstone belts occurred at 2740–2725 Ma and was accompanied and outlasted by calc-alkaline plutonism (2730–2715 Ma). Peraluminous plutonism at ca. 2700 Ma, possibly associated with low- to medium-pressure metamorphism, represents the culmination of the Archean tectonic cycle. Dating of metamorphic zircon and titanite in Archean gneissic rocks indicates that overprinting, high-grade metamorphism in the northwest part of the area (footwall of the Isortoq fault zone) is Paleoproterozoic (ca. 1820 Ma). A weaker, somewhat older thermal disturbance (ca. 1850–1840 Ma with large errors) is recorded in the hanging wall of this zone. Additional tectonothermal events at ca. 1500–1400 Ma and ca. 700 Ma may, respectively, correlate with Mesoproterozoic faulting and emplacement of the Franklin dyke swarm. Unlike their age-correlative counterparts in the Mary River area and on the mainland to the southwest, the greenstone belts at Eqe Bay lack abundant orthoquartzite and komatiitic volcanic rocks: calc-alkaline volcanic rocks predominate, suggesting a fundamentally different tectonic environment. Striking similarities, both in lithology and age, to greenstone belts of the Minto block of the Superior Province raises the question of Rae–Superior correlation.
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Beakhouse, Gary P., Shoufa Lin, and Sandra L. Kamo. "Magmatic and tectonic emplacement of the Pukaskwa batholith, Superior Province, Ontario, CanadaThis article is one of a series of papers published in this Special Issue on the theme of Geochronology in honour of Tom Krogh." Canadian Journal of Earth Sciences 48, no. 2 (February 2011): 187–204. http://dx.doi.org/10.1139/e10-048.

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The Neoarchean Pukaskwa batholith consists of pre-, syn-, and post-tectonic phases emplaced over an interval of 50 million years. Pre-tectonic phases are broadly synvolcanic and have a high-Al tonalite–trondhjemite–granodiorite (TTG) affinity interpreted to reflect derivation by partial melting of basaltic crust at lower crustal or upper mantle depths. Minor syn-tectonic phases slightly post-date volcanism and have geochemical characteristics suggesting some involvement or interaction with an ultramafic (mantle) source component. Magmatic emplacement of pre- and syn-tectonic phases occurred in the midcrust at paleopressures of 550–600 MPa and these components of the batholith are thought to be representative of the midcrust underlying greenstone belts during their development. Subsequent to emplacement of the syntectonic phases, and likely at approximately 2680 Ma, the Pukaskwa batholith was uplifted as a structural dome relative to flanking greenstone belts synchronously with ongoing regional sinistral transpressive deformation. The driving force for vertical tectonism is interpreted to be density inversion (Rayleigh–Taylor-type instabilities) involving denser greenstone belts and underlying felsic plutonic crust. The trigger for initiation of this process is interpreted to be an abrupt change in the rheology of the midcrust attributed to introduction of heat from the mantle attendant with slab breakoff or lithospheric delamination following the cessation of subduction. This process also led to partial melting of the intermediate to felsic midcrust generating post-tectonic granitic phases at approximately 2667 Ma. We propose that late density inversion-driven vertical tectonics is an inevitable consequence of horizontal (plate) tectonic processes associated with greenstone belt development within the Superior Province.
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38

Abraham, A. P. G., D. W. Davis, S. L. Kamo, and E. T. C. Spooner. "Geochronological constraints on late Archean magmatism deformation and gold–quartz vein mineralization in the northwestern Anialik River greenstone belt and igneous complex, Slave Province, N.W.T." Canadian Journal of Earth Sciences 31, no. 8 (August 1, 1994): 1365–83. http://dx.doi.org/10.1139/e94-119.

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Three phases of the Anialik River igneous complex (ARIC) give U–Pb zircon ages in the range −2705–2683 Ma, and three units from the adjacent northwestern Anialik River greenstone belt (ARGB) give ca. 2678 Ma ages. Titanite from unsheared ARIC rocks crystallized during localized metamorphism and deuteric alteration between 2693 and 2683 Ma. Hydrothermal titanite in wall rocks to gold-mineralized shear zones crystallized during early shear zone development (2670 ± 1 Ma) and was subsequently locally altered to rutile, with gold occurring within the rutile-bearing assemblage. Unaltered second-generation hydrothermal titanite, overgrowing the rutile assemblage, crystallized during later brittle–ductile movement (2656 ± 2 Ma) and provides a minimum age for gold mineralization. Relatively high 207Pb/204Pb ratios of Pb in gold-associated galena suggest that it was partly derived from significantly older crustal material, possibly underlying the igneous complex and greenstone belt. This interpretation is consistent with other evidence for the existence of > 3.0 Ga crustal rocks to the west of the study area. A late crosscutting granite gives an age of [Formula: see text] and is therefore part of the Pan-Slave tectono-thermal event. These results, and other data for the Slave Province, indicate temporal variations in the development and deformation of predeformational greenstone belts. The new ages show that regional deformation and metamorphism in the northwestern Slave Province followed shortly after major magmatism, and that gold mineralization might have occurred during the late Archean accretion of the greenstone belt and igneous complex to an older crustal domain to the west.
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Fedo, Christopher M., Kenneth A. Eriksson, and Tom G. Blenkinsop. "Geologic history of the Archean Buhwa Greenstone Belt and surrounding granite–gneiss terrane, Zimbabwe, with implications for the evolution of the Limpopo Belt." Canadian Journal of Earth Sciences 32, no. 11 (November 1, 1995): 1977–90. http://dx.doi.org/10.1139/e95-151.

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The Buhwa Greenstone Belt (BGB) of southern Zimbabwe is the only major greenstone belt in the Archean Zimbabwe Craton directly adjacent to the granulite-facies rocks that constitute the Northern Marginal Zone of the Limpopo Belt. The deformational history and assembly of the BGB shed light on the evolution of the Northern Marginal Zone – Zimbabwe Craton transition. Assembly of the region began with deposition of the dominantly sedimentary cover succession at ~3.0 Ga on banded gneisses of the ~3.5 Ga Tokwe segment. At ~2.9 Ga the northern margin of the greenstone belt experienced kilometres of ductile, oblique-slip, dextral shearing. This shear zone was later intruded by the granitic to tonalitic ~2.9 Ga Chipinda batholith. The remaining events recognized in the region occurred during the time span 2.9–2.5 Ga. Northwest-directed thrusting of the Northern Marginal Zone over the Zimbabwe Craton took place along a collection of discrete, typically metre-wide shear zones, which collectively form the tectonic break between the Zimbabwe Craton and the Northern Marginal Zone. In response to thrusting, the cover succession and surrounding granitoids were folded and underwent regional greenschist-facies metamorphism. Two suites of potassic granites were emplaced north and south of the greenstone belt towards the end of thrusting. Plutonism was followed by conjugate faulting and later filling of the fractures by the Great Dyke of Zimbabwe. The youngest events may have occurred between ~2.5 and ~2.0 Ga, and include sinistral shearing along the southern margin of the belt, transecting cleavage formation, and open folding as a result of northeast-directed crustal shortening.
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40

Spray, John G., and Lyle A. Burgess. "Landsat MSS imagery applied to geological investigation of the Norseman area granitoid–greenstone terrain, southeast Yilgarn Block, Western Australia." Geological Magazine 122, no. 6 (November 1985): 587–94. http://dx.doi.org/10.1017/s0016756800032003.

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AbstractInteractively processed Landsat MSS imagery has been used as an aid to studying the regional geology of approximately 10 800 km2 of terrain at the southeast margin of the Archaean Yilgarn Block in Western Australia. The technique proved successful in extending positions of known lithological contacts and lineaments into poorly exposed, inaccessible areas and in revealing new geological features, especially faults, previously unrecognized at ground level. During this investigation the distribution of granitoids and greenstones was more precisely defined, internal greenstone structures highlighted and three main fault trends were identified: (1) NW–NNW and (2) ENE, both within Archaean shield, and (3) NE–NNE within the transition to adjacent Proterozoic mobile belt. In order for the most information to be extracted from Landsat MSS images it is recommended that, whenever possible, image processing should follow ground-based studies as well as precede them, and that field geologist and Landsat specialist should work at the image processing system together.
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41

Staudigel, Hubert, Harald Furnes, and Maarten DeWit. "Paleoarchean trace fossils in altered volcanic glass." Proceedings of the National Academy of Sciences 112, no. 22 (May 18, 2015): 6892–97. http://dx.doi.org/10.1073/pnas.1421052112.

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Microbial corrosion textures in volcanic glass from Cenozoic seafloor basalts and the corresponding titanite replacement microtextures in metamorphosed Paleoarchean pillow lavas have been interpreted as evidence for a deep biosphere dating back in time through the earliest periods of preserved life on earth. This interpretation has been recently challenged for Paleoarchean titanite replacement textures based on textural and geochronological data from pillow lavas in the Hooggenoeg Complex of the Barberton Greenstone Belt in South Africa. We use this controversy to explore the strengths and weaknesses of arguments made in support or rejection of the biogenicity interpretation of bioalteration trace fossils in Cenozoic basalt glasses and their putative equivalents in Paleoarchean greenstones. Our analysis suggests that biogenicity cannot be taken for granted for all titanite-based textures in metamorphosed basalt glass, but a cautious and critical evaluation of evidence suggests that biogenicity remains the most likely interpretation for previously described titanite microtextures in Paleoarchean pillow lavas.
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42

Pouclet, André, Siaka Doumbia, and Max Vidal. "Geodynamic setting of the Birimian volcanism in central Ivory Coast (western Africa) and its place in the Palaeoproterozoic evolution of the Man Shield." Bulletin de la Société Géologique de France 177, no. 2 (March 1, 2006): 105–21. http://dx.doi.org/10.2113/gssgfbull.177.2.105.

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Abstract Palaeoproterozoic volcanic formations having different geochemical features are described in the Katiola-Marabadiassa area (Central Ivory Coast). They consist of (i) metamorphic mafic rocks belonging to the greenstone belts, (ii) rhyodacites intruded into the greenstone belts and interpreted as sub-volcanic apophyses of TTG plutons, and (iii) calc-alkaline andesitic lava interbedded in the lower sedimentary pile of the Bandama Basin. The greenstone belt rocks have a magmatic signature of ocean floor tholeiites. They were generated from moderate partial melting of a fairly depleted spinel lherzolite source. The rhyodacites show the same compositions as the TTG granitoids of the belt. These TTGs generated from melting of garnet-bearing amphibolite, derived from subducted oceanic crust, but also from peridotite melting of the fertilized mantle wedge. The andesites show a common composition of active continental margin potassic calc-alkaline lavas. However, they do not constitute a volcanic belt, but belong to an intracontinental basin settled in a wrench tectonic system. They probably generated from remelting of sub-crustal metasomatised mantle. The tectono-magmatism story of the Katiola-Marabadiassa area comprises four stages. A similar evolution is found in other belt-and-basin areas in Ivory Coast. A review of lithostratigraphic and chronological data of the Birimian terrains leads us to compare the four-stage model of the Central Ivory Coast to the West-African Palaeoproterozoic evolution. The first stage corresponds to ocean crust formation, by mid-ocean ridge accretion and volcanic arc building. The second stage, partly overlapping the previous one, is convergent and lasted from oceanic crust stacking to TTG and associated greenstone belt formation. It led to a protocontinental crust accretion by docking of granitized blocks, from ca 2200 Ma to 2110 Ma. The third stage corresponds to the formation of intracontinental basins by reorganization of the granitoid-greenstone shields and of the remnant oceanic basins, between 2118 Ma and 2093 Ma. It was associated with calc-alkaline magma production. The fourth stage is characterized by transtensional stress, with the closure of the basins by left-lateral wrenching along N-S faults, and by emplacement of new potassic granitoids until 2072 Ma.
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43

Zhiltsova, I. V., M. V. Ruzina, M. L. Malova, N. V. Bilan, O. A. Tereshkova, and A. S. Gardysh. "Analysis of the spatial patterns in localization of gold mineralization relative to the system of deep faults in the Chortomlyk greenstone structure of the Ukrainian shield." Journal of Geology, Geography and Geoecology 27, no. 3 (January 8, 2019): 537–45. http://dx.doi.org/10.15421/111878.

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The results of analysisof the patterns of the spatial relationship between hydrothermal gold ore formations and the zones of metasomatites and systems of deep faults within the Chortomlyk greenstone structure of the Middle Pridniprovie megablock in the Ukrainian Shield are given. As a result of studying the localization conditions of gold mineralization, it was established that the gold-bearing mineralization is confined to tectonically fractured zones and is localized among metasomatically altered rocks. The hydrothermal series of metasomatites in the Chortomlyk greenstone structure is represented by greisens, propylites, amphibole-carbonate metasomatites and listvenite-berezites. The mineralization of Au and Mo is associated with metasomatites of the greisen type. The study of spatial relationship between the fields of metasomatites and the gold mineralization and zones of deep faults revealed that the closest relationship is expressed with systems of faults with azimuths of 0° and 270°, 17° and 287°, 77° and 347°. The results of the studies allowed us to develop a newprospecting criterion, which, in turn allows us to state that the gold mineralization within the Chortomlyk greenstone structure is spatially confined to metasomatites related to the schistosity, fracture, millonitization, and cataclase zones with high content of sulphide mineralization. These zones are localized in nodes of intersecting faults of the first order of the system 77° and 347° with discontinuous violations of high orders of azimuths of 0° and 270°, 17°and 287°. The results of the research can be used to develop a set of predictive criteria and the allocation of promising sites of hydrothermal mineralization of gold within the Chortomlyk greenstone structure of the Middle Pridniprovie megablock in the Ukrainian shield.
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Corfu, Fernando, and Shoufa Lin. "Geology and U-Pb geochronology of the Island Lake greenstone belt, northwestern Superior Province, Manitoba." Canadian Journal of Earth Sciences 37, no. 9 (September 1, 2000): 1275–86. http://dx.doi.org/10.1139/e00-043.

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Mapping and U-Pb geochronology have been used to examine the tectonic and depositional history of the Archean Island Lake greenstone belt in the northwestern Superior Province. The Island Lake greenstone belt comprises two main supracrustal successions, the older Hayes River Group and the younger Island Lake Group. Zircon data for two volcanic units from the Hayes River Group provide identical ages of 2852 ± 1.5 Ma, whereas a turbidite of this group contains a detrital zircon population with ages between 2858 and 2847 Ma. Younger intrusive events include the emplacement of tonalite in the southern batholith at 2825 ± 2 Ma and the Whiteway Island gabbro at 2807 ± 1 Ma. A wacke at the base of the Island Lake Group is dominated by detrital zircon grains yielding ages between 2830 and 2821 Ma, the latter defining a maximum age of sedimentation. A relatively early time of deposition of the lower stratigraphic sections of the Island Lake Group is also supported by an age of 2744 ± 2 Ma obtained for a crosscutting tonalite. By contrast, two turbidite horizons from higher stratigraphic levels of the Island Lake Group contain detrital zircon populations with ages mostly younger than 2730 Ma, the youngest zircon grains providing maximum ages of sedimentation at 2722 and 2712 Ma, respectively. Our results confirm the protracted evolution of the greenstone belt and show in particular that major sedimentary processes were active throughout the main stages of volcanism of the belt. This pattern of protracted sedimentation is comparable to that observed in other greenstone belts of the northwestern Superior Province, all of which developed on pre-Kenoran crust.
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45

Corkery, M. T., D. W. Davis, and P. G. Lenton. "Geochronological constraints on the development of the Cross Lake greenstone belt, northwest Superior Province, Manitoba." Canadian Journal of Earth Sciences 29, no. 10 (October 1, 1992): 2171–85. http://dx.doi.org/10.1139/e92-172.

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Recent 1: 20 000 mapping combined with 11 age determinations from metavolcanic, metaplutonic, and metasedimentary rocks in the Cross Lake greenstone belt provide a framework for interpreting the stratigraphic, structural, intrusive, and metamorphic evolution of the belt. These data, in combination with U–Pb ages from adjacent granitoid domains, are used to model a cratonizing event in the northwest Superior Province.The Cross Lake greenstone belt is made up of three distinct unconformable groups of supracrustal rocks: (i) the Pipestone Lake Group (2760 Ma), a thick sequence of pillowed and massive tholeiitic basalt flows and related high level gabbros, inter-preted as a back-arc spreading sequence; (ii) the Gunpoint Group (2730 Ma), a fining-upward sequence of clastic sediments interbedded with rhyodacitic fragmental volcanic rocks; and (iii) the Cross Lake Group (<2710 Ma), a fining-upward, fluvial–marine clastic sedimentary sequence, with shoshonitic volcanic rocks near the top, deposited in a restricted basin. Angular unconformities occur between (i) the Pipestone Lake Group and the overlying Gunpoint and Cross Lake groups, and (ii) the Gunpoint Group and the younger Cross Lake Group.The greenstone belt is flanked by the plutonic Molson Lake Domain on the south and the largely metaplutonic Pikwitonei and granite–greenstone Gods Lake domains on the northwest. The northern contact is a major northeast-trending fault system with a dextral strike-slip component and vertical component indicative of relative uplift of the northwest side. The southern contact is a much broader zone of deformation in which a number of east-southeast-trending dextral fault zones imbricate Pipestone Lake and Gunpoint Group supracrustal rocks and, to a lesser extent, Molson Lake plutonic rocks.
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46

Inza, Coulibaly, Kouamelan Alain Nicaise, Djro Sagbrou Chérubin, and Coulibaly Yacouba. "Petrographie Des Volcanites Et Plutonites De La Partie Sud Du Sillon Volcano-Sedimentaire De Toumodi-Fetekro (Cote D’ivoire)." European Scientific Journal, ESJ 13, no. 30 (October 31, 2017): 199. http://dx.doi.org/10.19044/esj.2017.v13n30p199.

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The southern part of Toumodi-Fètêkro greenstone belt is located in the Center - Southeast of Ivory Coast. Petrographic study of volcanic and plutonic rocks shows three units. The first unit is composed of basaltic to rhyolitic lavas which imply effusive character. Then we have volcanosedimentary unit composed of pyroclastic formations (lapilli tuff, breccia, ash deposit and ignimbrites) and the pillow-lavas. Indeed, the presence of this last shows clearly that an explosive volcanism and a submarine effusive volcanism have occurred during during the setting of Toumodi-Fètêkro belt. Plutonic unit is constituted of gabbroic to granitic rocks. Sericite, chlorite, epidote observed in these rocks are consistent with the impacts of greenschist facies metamorphism. The rocks of the southern part of the Toumodi-Fètêkro greenstone belt are formed in a subduction context rather than in oceanic plateaus context because of the old inheritance, sometimes of Archean age, found somewhere in theBirimiandomain. The lithologies of the southern part of Toumodi-Fètêkro meet elsewhere in the other Birimian greenstone belts. Also, these lithologies are affected by a hydrothermal alteration due to the abundant veins of quartz, carbonates, sericite, chlorite, epidote, sulphides and oxides. However, volcanic show in some places amphibolit facies metamorphism.
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47

Jackson, S. L., and R. H. Sutcliffe. "Central Superior Province geology: evidence for an allochthonous, ensimatic, southern Abitibi greenstone belt." Canadian Journal of Earth Sciences 27, no. 4 (April 1, 1990): 582–89. http://dx.doi.org/10.1139/e90-054.

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Published U–Pb geochronological, geological, and petrochemical data suggest that there are late Archean ensialic greenstone belts (GB) (Michipicoten GB and possibly the northern Abitibi GB), ensimatic greenstone belts (southern Abitibi GB and Batchawana GB), and possibly a transitional ensimatic–ensialic greenstone belt (Swayze GB) in the central Superior Province. This lateral crustal variability may preclude simple correlation of the Michipicoten GB and its substrata, as exposed in the Kapuskasing Uplift, with that of the southern Abitibi GB. Furthermore, this lateral variability may have determined the locus of the Kapuskasing Uplift. Therefore, although the Kapuskasing Uplift provides a useful general crustal model, alternative models of crustal structure and tectonics for the southern Abitibi GB warrant examination.Thrusting of a juvenile, ensimatic southern Abitibi GB over a terrane containing evolved crust is consistent with (i) the structural style of the southern Abitibi GB; (ii) juvenile southern Abitibi GB metavolcanic rocks intruded by rocks having an isotopically evolved, older component; and (iii) Proterozoic extension that preserved low-grade metavolcanic rocks within the down-dropped Cobalt Embayment, which is bounded by higher grade terranes to the east and west.
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48

Menéndez, Alfredo. "Greenstone belts of the Venezuelan Guayana Shield - A stratigraphie revision." Global Tectonics and Metallogeny 7, no. 2 (December 1, 1999): 83–84. http://dx.doi.org/10.1127/gtm/7/1999/83.

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49

Hicks, N., and D. J. C. Gold. "A reinterpretation of the Archaean stratigraphy south of Nkandla, southern Kaapvaal Craton, South Africa: Geophysical and stratigraphic constraints on a sheared granitoid-greenstone remnant." South African Journal of Geology 124, no. 3 (September 1, 2021): 685–98. http://dx.doi.org/10.25131/sajg.124.0025.

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Abstract A new lithostratigraphic framework based upon a review of historic data, field mapping and remote sensing, including aerial photography, high-resolution airborne aeromagnetic and radiometric data, is proposed for the Archaean geology along the southeastern margin of the Kaapvaal Craton, South Africa. A synthesis of new and existing data reveals that previously accepted lithostratigraphic schemes require complete revision, with reinterpretations identifying multiple major shear zones and previously unidentified granitoid successions along the margin of the craton. In this new lithostratigraphic framework, lithologies of the Southern Syncline previously correlated with the Nsuze Group of the Pongola Supergroup, are redefined as greenstone lithologies associated with the Ilangwe Greenstone Belt. The geology of the Nkandla region can be subdivided into five distinct geophysical domains including: (i) an extension of the Ilangwe Greenstone Belt, (Domain 1) which is subdivided into; a lower volcanic succession, the Thathe Formation, comprising pillow and amygdaloidal volcanics; the adjoining Sabiza Formation, comprising pillow volcanics exposed in the southeast of the study area; the volcano-sedimentary Mtshwili Formation, which overlies the Thathe and Sabiza formations, consisting of quartz (sericite) schist, phyllite, metavolcanics and iron formation; the Nomangci Formation, which occurs as a region of highly deformed quartz-kyanite-sericite schists, and the Simbagwezi Formation, which comprises maroon to green phyllites and schists in the north of the study area. (ii) granitoids of the Impisi Granitoid Suite (Domain 2) which border the greenstone succession to the north, intruding the Nomangci and Simbagwezi formations. (iii) a southern complex of sheared granitoids termed the Umgabhi Granitoid Suite (Domain 3), which intrudes the Thathe, Sabiza and Mtshwili formations. (iv) The two remaining domains, comprise the Mesoproterozoic Mfongosi and Ntingwe Groups (Domain 4) and Mesoarchaean volcano-sedimentary sequences of the Pongola Supergroup (Domain 5).
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50

Benn, Keith, Edward W. Sawyer, and Jean-Luc Bouchez. "Orogen parallel and transverse shearing in the Opatica belt, Quebec: implications for the structure of the Abitibi Subprovince." Canadian Journal of Earth Sciences 29, no. 11 (November 1, 1992): 2429–44. http://dx.doi.org/10.1139/e92-191.

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The late Archean Opatica granitoid-gneiss belt is situated within the northern Abitibi Subprovince, along the northern margin of the Abitibi greenstone belt. Approximately 200 km of structural section was mapped along three traverses within the previously unstudied Opatica belt. The earliest preserved structures are penetrative foliations and stretching and mineral lineations recording regional ductile shearing (D1). Late-D1 deformation was concentrated into kilometre-scale ductile fault zones, typically with L > S tectonite fabrics. Two families of lineations are associated with D1, indicating shearing both parallel and transverse to the east-northeast trend of the belt. Lineations trending east-northeast or northwest–southeast tend to be dominant within domains separated by major fault zones. In light of the abundant evidence for early north–south compression documented throughout southern Superior Province, including the Abitibi greenstone belt, D1 is interpreted in terms of mid-crustal thrusting, probably resulting in considerable crustal thickening. Movement-sense indicators suggest that thrusting was dominantly southward vergent. D2 deformation resulted in the development of vertical, regional-scale dextral and sinistral transcurrent fault zones and open to tight upright horizontal folds of D1 fabrics. In the context of late Archean orogenesis in southern Superior Province, the tectonic histories of the Abitibi and Opatica belts should not be considered separately. The Opatica belt may correlate with the present-day mid-crustal levels of the Abitibi greenstone belt, and to crystalline complexes within the Abitibi belt. It is suggested that the Abitibi Subprovince should be viewed, at the regional scale, as a dominantly southward-vergent orogenic belt. This work demonstrates that structural study of granitoid-gneiss belts adjacent to greenstone belts can shed considerable light on the regional structure and structural evolution of late Archean terranes.
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