The Generation and Evolution of Archean Continental Crust in The
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Uplift, Rupture, and Rollback of the Farallon Slab Reflected in Volcanic
PUBLICATIONS Journal of Geophysical Research: Solid Earth RESEARCH ARTICLE Uplift, rupture, and rollback of the Farallon slab reflected 10.1002/2017JB014517 in volcanic perturbations along the Yellowstone Key Points: adakite hot spot track • Volcanic perturbations in the Cascadia back-arc region are derived from uplift Victor E. Camp1 , Martin E. Ross2, Robert A. Duncan3, and David L. Kimbrough1 and dismemberment of the Farallon slab from ~30 to 20 Ma 1Department of Geological Sciences, San Diego State University, San Diego, California, USA, 2Department of Earth and • Slab uplift and concurrent melting 3 above the Yellowstone plume Environmental Sciences, Northeastern University, Boston, Massachusetts, USA, College of Earth, Ocean, and Atmospheric promoted high-K calc-alkaline Sciences, Oregon State University, Corvallis, Oregon, USA volcanism and adakite generation • Creation of a seismic hole beneath eastern Oregon resulted from thermal Abstract Field, geochemical, and geochronological data show that the southern segment of the ancestral erosion and slab rupture, followed by Cascades arc advanced into the Oregon back-arc region from 30 to 20 Ma. We attribute this event to thermal a period of slab rollback uplift of the Farallon slab by the Yellowstone mantle plume, with heat diffusion, decompression, and the release of volatiles promoting high-K calc-alkaline volcanism throughout the back-arc region. The greatest Supporting Information: • Supporting Information S1 degree of heating is expressed at the surface by a broad ENE-trending zone of adakites and related rocks • Data Set S1 generated by melting of oceanic crust from the Farallon slab. A hiatus in eruptive activity began at ca. • Data Set S2 22–20 Ma but ended abruptly at 16.7 Ma with renewed volcanism from slab rupture occurring in two separate • Data Set S3 regions. -
Community Involvement in Geoconservation: a Conceptual Approach Based on the Geoheritage of South Angola
Sustainability 2015, 7, 4893-4918; doi:10.3390/su7054893 OPEN ACCESS sustainability ISSN 2071-1050 www.mdpi.com/journal/sustainability Article Community Involvement in Geoconservation: A Conceptual Approach Based on the Geoheritage of South Angola Alexandre Oliveira Tavares 1,2,*, Maria Helena Henriques 2,3,†, Artur Domingos 4,† and Abel Bala 5,† 1 Centre for Social Studies, University of Coimbra (Polo II), Rua Sílvio Lima, 3030-790 Coimbra, Portugal 2 Department of Earth Sciences, University of Coimbra (Polo II), Rua Sílvio Lima, 3030-790 Coimbra, Portugal 3 Geosciences Centre, University of Coimbra (Polo II), Rua Sílvio Lima, 3030-790 Coimbra, Portugal; E-Mail: [email protected] 4 Magistério Primário do Lubango-Nambambe, Lubango, Angola; E-Mail: [email protected] 5 Instituto Superior Politécnico da Tundavala and Escola Secundária do 2° Ciclo/Quilengues, Huíla, Angola; E-Mail: [email protected] † These authors contributed equally to this work. * Author to whom correspondence should be addressed; E-Mail: [email protected]; Tel.: +351-239-860-566; Fax: +351-239-860-501. Academic Editor: Marc A. Rosen Received: 24 March 2015 / Accepted: 20 April 2015 / Published: 24 April 2015 Abstract: In this work, it is argued that effective protection of geological objects displaying heritage value requires the local community’s involvement in all geoconservation actions, i.e., inventory, evaluation, conservation, valuation and monitoring procedures, and not only at the final part of the process, when it is expected from local communities that the physical integrity of such objects is guaranteed. Community involvement in geoheritage inventory and evaluation procedures can be appraised by using a classification system that integrates both the geoheritage properties displayed by the geological objects and usually recognized by geoscientists (i.e., relevance grade) and the social role attributed to geological objects by communities outside Earth scientists that arise from the public perception of such objects (i.e., abstract perceptiveness). -
Two Contrasting Phanerozoic Orogenic Systems Revealed by Hafnium Isotope Data William J
ARTICLES PUBLISHED ONLINE: 17 APRIL 2011 | DOI: 10.1038/NGEO1127 Two contrasting Phanerozoic orogenic systems revealed by hafnium isotope data William J. Collins1*(, Elena A. Belousova2, Anthony I. S. Kemp1 and J. Brendan Murphy3 Two fundamentally different orogenic systems have existed on Earth throughout the Phanerozoic. Circum-Pacific accretionary orogens are the external orogenic system formed around the Pacific rim, where oceanic lithosphere semicontinuously subducts beneath continental lithosphere. In contrast, the internal orogenic system is found in Europe and Asia as the collage of collisional mountain belts, formed during the collision between continental crustal fragments. External orogenic systems form at the boundary of large underlying mantle convection cells, whereas internal orogens form within one supercell. Here we present a compilation of hafnium isotope data from zircon minerals collected from orogens worldwide. We find that the range of hafnium isotope signatures for the external orogenic system narrows and trends towards more radiogenic compositions since 550 Myr ago. By contrast, the range of signatures from the internal orogenic system broadens since 550 Myr ago. We suggest that for the external system, the lower crust and lithospheric mantle beneath the overriding continent is removed during subduction and replaced by newly formed crust, which generates the radiogenic hafnium signature when remelted. For the internal orogenic system, the lower crust and lithospheric mantle is instead eventually replaced by more continental lithosphere from a collided continental fragment. Our suggested model provides a simple basis for unravelling the global geodynamic evolution of the ancient Earth. resent-day orogens of contrasting character can be reduced to which probably began by the Early Ordovician12, and the Early two types on Earth, dominantly accretionary or dominantly Paleozoic accretionary orogens in the easternmost Altaids of Pcollisional, because only the latter are associated with Wilson Asia13. -
2014 Journal Articles, Books, Book Chapters and Conference Papers
2014 Journal articles, books, book chapters and conference papers ACADEMIC DEVELOPMENT & SUPPORT – CHAPTERS – Motshoane Puleng PL and McKenna S. "More than agency: the multiple mechanisms affecting postgraduate education" in Pushing Boundaries in Postgraduate Supervision. 2014. SUN Press. ISBN: 978-1-920689-15-5 – CONFERENCE PROCEEDINGS – Govender Cookie CM and Taylor Susanne S. "Student reflections on the pilot WIL partnership capacity building model in a human resource management qualification ". National Conference on Work Integrated Learning: Building Capacity. 2014. Australian Collaborative Education Network (ACEN) Limited. ISBN: 978-0-9805706-0-1 Lautenbach Geoffrey GV and Amory Alan AM. "Learning with technology: an assessment of learning design and knowledge construction online". World Conference on Educational Media & Technology (EdMedia 2014). 2014. Association for the Advancement of Computing in Education (AACE). ISBN: 978-1-939797-08-7 Van Wyk Rene R, Morgan Brandon B and Vorster Paul PP. "Preliminary validation of a collective intelligence questionnaire". 31st Pan Pacific Conference: Designing the Shared Future through Co- Creation. 2014. Pan-Pacific Business Association. ISBN: 1-931649-27-4 – JOURNALS – Amory Alan AM. "Tool-mediated authentic learning in an educational technology course: a designed- based innovation". Interactive Learning Environments (ISI). 2014. Vol. 22 (4) Kane Sandra S, Dube Cecilia CM and Lear Miriam MR. "Reflections on the role of meta-cognition in student reading and learning at higher education level". Africa Education Review (Educare). (DHET). 2014. Vol. 11 (4) Mavunga George G, Kufakunesu P and Mutambwa J. "'Iwe' or 'imi'? An analysis of terms of address used by police officers at Mbare police station". Language Matters: Studies in the Languages of Africa (Language Matters: Studies in the Languages of Southern Africa) (DHET). -
Assembly, Configuration, and Break-Up History of Rodinia
Author's personal copy Available online at www.sciencedirect.com Precambrian Research 160 (2008) 179–210 Assembly, configuration, and break-up history of Rodinia: A synthesis Z.X. Li a,g,∗, S.V. Bogdanova b, A.S. Collins c, A. Davidson d, B. De Waele a, R.E. Ernst e,f, I.C.W. Fitzsimons g, R.A. Fuck h, D.P. Gladkochub i, J. Jacobs j, K.E. Karlstrom k, S. Lu l, L.M. Natapov m, V. Pease n, S.A. Pisarevsky a, K. Thrane o, V. Vernikovsky p a Tectonics Special Research Centre, School of Earth and Geographical Sciences, The University of Western Australia, Crawley, WA 6009, Australia b Department of Geology, Lund University, Solvegatan 12, 223 62 Lund, Sweden c Continental Evolution Research Group, School of Earth and Environmental Sciences, University of Adelaide, Adelaide, SA 5005, Australia d Geological Survey of Canada (retired), 601 Booth Street, Ottawa, Canada K1A 0E8 e Ernst Geosciences, 43 Margrave Avenue, Ottawa, Canada K1T 3Y2 f Department of Earth Sciences, Carleton U., Ottawa, Canada K1S 5B6 g Tectonics Special Research Centre, Department of Applied Geology, Curtin University of Technology, GPO Box U1987, Perth, WA 6845, Australia h Universidade de Bras´ılia, 70910-000 Bras´ılia, Brazil i Institute of the Earth’s Crust SB RAS, Lermontova Street, 128, 664033 Irkutsk, Russia j Department of Earth Science, University of Bergen, Allegaten 41, N-5007 Bergen, Norway k Department of Earth and Planetary Sciences, Northrop Hall University of New Mexico, Albuquerque, NM 87131, USA l Tianjin Institute of Geology and Mineral Resources, CGS, No. -
Lithium Enrichment in the No. 21 Coal of the Hebi No. 6 Mine, Anhe Coalfield, Henan Province, China
minerals Article Lithium Enrichment in the No. 21 Coal of the Hebi No. 6 Mine, Anhe Coalfield, Henan Province, China Yingchun Wei 1,* , Wenbo He 1, Guohong Qin 2, Maohong Fan 3,4 and Daiyong Cao 1 1 State Key Laboratory of Coal Resources and Safe Mining, College of Geoscience and Surveying Engineering, China University of Mining and Technology, Beijing 100083, China; [email protected] (W.H.); [email protected] (D.C.) 2 College of Resources and Environmental Science, Hebei Normal University, Shijiazhuang 050024, China; [email protected] 3 Departments of Chemical and Petroleum Engineering, and School of Energy Resources, University of Wyoming, Laramie, WY 82071, USA; [email protected] 4 School of Civil and Environmental Engineering, Georgia Institute of Technology, Mason Building, 790 Atlantic Drive, Atlanta, GA 30332, USA * Correspondence: [email protected] Received: 18 May 2020; Accepted: 3 June 2020; Published: 5 June 2020 Abstract: Lithium (Li) is an important strategic resource, and with the increasing demand for Li, there are some limitations in the exploitation and utilization of conventional deposits such as the pegmatite-type and brine-type Li deposits. Therefore, it has become imperative to search for Li from other sources. Li in coal is thought to be one of the candidates. In this study, the petrology, mineralogy, and geochemistry of No. 21 coal from the Hebi No. 6 mine, Anhe Coalfield, China, was reported, with an emphasis on the distribution, modes of occurrence, and origin of Li. The results show that Li is enriched in the No. 21 coal, and its concentration coefficient (CC) value is 6.6 on average in comparison with common world coals. -
Tectonostratigraphic Evolution of the North China Craton and the Qilian
RESEARCH ARTICLE Punctuated Orogeny During the Assembly of Asia: 10.1029/2020TC006503 Tectonostratigraphic Evolution of the North China Key Points: Craton and the Qilian Shan From the Paleoproterozoic to • The western North China craton records at least three orogenies from Early Paleozoic the Paleoproterozoic to the early Paleozoic Chen Wu1 , Andrew V. Zuza2 , An Yin3 , Xuanhua Chen4, Peter J. Haproff5 , Jie Li6, • Mesoproterozoic strata in North Bing Li2,4 , and Lin Ding1,7 China, Tarim, and the Qilian Shan are similar, suggesting continuity 1Key Laboratory of Continental Collision and Plateau Uplift, Institute of Tibetan Plateau Research, and Center for among these continents 2 • Gondwana was not affixed to the Excellence in Tibetan Plateau Earth Sciences, Chinese Academy of Sciences, Beijing, China, Nevada Bureau of Mines 3 western margin of North China in and Geology, University of Nevada, Reno, NV, USA, Department of Earth, Planetary and Space Sciences, University of the Neoproterozoic-early Paleozoic California, Los Angeles, CA, USA, 4Chinese Academy of Geological Sciences, Beijing, China, 5Department of Earth and Ocean Sciences, University of North Carolina, Wilmington, NC, USA, 6School of Earth Sciences and Resources, China 7 Supporting Information: University of Geosciences (Beijing), Beijing, China, University of Chinese Academy of Sciences, Beijing, China • Supporting Information S1 Abstract The Proterozoic-Phanerozoic evolution of the Tarim and North China cratons is integral to Correspondence to: the construction of the Eurasian continent. Throughout the Paleozoic, these continents were bound by C. Wu and A. V. Zuza, the Paleo-Asian and Tethyan Oceans to the north and south, respectively, and, thus, their paleogeography [email protected]; [email protected]; is critical to reconstructions of the oceanic domains. -
Balkatach Hypothesis: a New Model for the Evolution of the Pacific, Tethyan, and Paleo-Asian Oceanic Domains
Research Paper GEOSPHERE Balkatach hypothesis: A new model for the evolution of the Pacific, Tethyan, and Paleo-Asian oceanic domains 1,2 2 GEOSPHERE, v. 13, no. 5 Andrew V. Zuza and An Yin 1Nevada Bureau of Mines and Geology, University of Nevada, Reno, Nevada 89557, USA 2Department of Earth, Planetary, and Space Sciences, University of California, Los Angeles, California 90095-1567, USA doi:10.1130/GES01463.1 18 figures; 2 tables; 1 supplemental file ABSTRACT suturing. (5) The closure of the Paleo-Asian Ocean in the early Permian was accompanied by a widespread magmatic flare up, which may have been CORRESPONDENCE: avz5818@gmail .com; The Phanerozoic history of the Paleo-Asian, Tethyan, and Pacific oceanic related to the avalanche of the subducted oceanic slabs of the Paleo-Asian azuza@unr .edu domains is important for unraveling the tectonic evolution of the Eurasian Ocean across the 660 km phase boundary in the mantle. (6) The closure of the and Laurentian continents. The validity of existing models that account for Paleo-Tethys against the southern margin of Balkatach proceeded diachro- CITATION: Zuza, A.V., and Yin, A., 2017, Balkatach hypothesis: A new model for the evolution of the the development and closure of the Paleo-Asian and Tethyan Oceans criti- nously, from west to east, in the Triassic–Jurassic. Pacific, Tethyan, and Paleo-Asian oceanic domains: cally depends on the assumed initial configuration and relative positions of Geosphere, v. 13, no. 5, p. 1664–1712, doi:10.1130 the Precambrian cratons that separate the two oceanic domains, including /GES01463.1. the North China, Tarim, Karakum, Turan, and southern Baltica cratons. -
Experimental Constraints on Adakitic Metasomatism of Mantle Wedge Peridotites Below Patagonia
O EOL GIC G A D D A E D C E I H C I L E O S F u n 2 d 6 la serena octubre 2015 ada en 19 Experimental constraints on adakitic metasomatism of mantle wedge peridotites below Patagonia Alexandre Corgne * and Manuel Schilling D. Instituto de Ciencias de la Tierra, Universidad Austral de Chile, Campus Isla Teja, Valdivia, Chile *Contact email: [email protected] Abstract. We performed a series of high-pressure (1.5 and Quaternary alkali lavas in the back-arc region (e.g. GPa) and high-temperature (1000-1300 ºC) experiments to Stern and Kilian, 1996; Gorring et al., 1997). The back-arc investigate the geochemical imprints of adakitic lavas are hosts of frequent mantle xenoliths, the study of metasomatism on mantle wedge peridotite. Reaction which has contributed to a better understanding of the couples were prepared using a powdered adakite from petrological and geochemical variability of the sub- Cerro Pampa (Argentina) placed next to a fragment of continental lithospheric mantle (e.g. Stern et al., 1990, spinel lherzolite from Pali Aike (Chile). Preliminary results 1999; Gorring and Kay, 2000; Laurora et al., 2001; show that the main changes in phase relations are Bertotto, 2002; Kilian and Stern, 2002; Bjerg et al., 2005, incongruent dissolution of olivine and associated 2009; Schilling et al., 2005; Rivalenti et al., 2004; Ntaflos precipitacion of secondary orthopyroxene, incongruent dissolution of primary spinel and formation of secondary et al., 2007; Wang et al., 2008; Dantas et al. 2009). spinel, as well as precipitation of secondary clinopyroxene and in some instances zoned plagioclase. -
Scottish Missionaries and the Circumcision Controversy in Kenya 1900-1960
International Review of Scottish Studies Vol. 28 2003 Kenneth Mufaka SCOTTISH MISSIONARIES AND THE CIRCUMCISION CONTROVERSY IN KENYA 1900-1960 t the turn of the century, the British High Commis- sioner in East Africa set up various areas in which A Christian missionaries were allowed exclusive influence. Scottish missionaries served the largest and most politically astute tribe in Kenya, the Kikuyu. Scottish educa- tion, combining a theoretical base with vocational training, attracted the best and the brightest of Kikuyu youths. This type of education provided a basis for future employment in government and industry. Jomo Kenyatta and Mbui Koinanage, both future nationalist leaders of Kenya, were converts and protégés of Scottish missionaries. However, in 1929, a sudden rift occurred between the Kikuyu Christian elders and congregations on one hand and their Scottish missionary patrons on the other side. The rift came about when the Scottish missionaries insisted that all Kikuyu Christians should take an oath against female initiation. Two thirds of the Kikuyu Christians left the mission church to form their own nationalist oriented churches. The rise of nationalistic feeling among Kenyans can be traced to this controversy. The issue of female circum- cision seems to have touched on all the major ingredients that formed the basis of African nationalist alienation from colo- nial rule. This article argues that the drama of 1929 was a rehearsal of the larger drama of the Mau Mau in 1950-1960 that put an end to colonial rule in Kenya. Though initiation practices were widespread in Kenya and the neighboring Sudan, the Scottish missionaries were unaware of them until 1904. -
Deconvolving the Pre-Himalayan Indian Margin E Tales of Crustal Growth and Destruction
Geoscience Frontiers 10 (2019) 863e872 HOSTED BY Contents lists available at ScienceDirect China University of Geosciences (Beijing) Geoscience Frontiers journal homepage: www.elsevier.com/locate/gsf Research Paper Deconvolving the pre-Himalayan Indian margin e Tales of crustal growth and destruction Christopher J. Spencer a,b,*, Brendan Dyck c, Catherine M. Mottram d,e, Nick M.W. Roberts b, Wei-Hua Yao a,f, Erin L. Martin a a Earth Dynamics Research Group, The Institute for Geoscience Research (TIGeR), Department of Applied Geology, Curtin University, 6845, Perth, Australia b NERC Isotope Geosciences Laboratory, British Geological Survey, Keyworth, Nottingham, NG12 5GG, UK c Department of Earth Sciences, Simon Fraser University, University Drive, Burnaby V5A 1S6, Canada d Department of Environment, Earth and Ecosystems, The Open University, Walton Hall, Milton Keynes, MK7 6AA, UK e School of Earth and Environmental Sciences, University of Portsmouth, Portsmouth, PO1 3QL, UK f Schoolof Earth Sciences and Engineering, SunYat-sen University, Guangzhou 510275, China article info abstract Article history: The metamorphic core of the Himalaya is composed of Indian cratonic rocks with two distinct crustal Received 30 November 2017 affinities that are defined by radiogenic isotopic geochemistry and detrital zircon age spectra. One is Received in revised form derived predominantly from the Paleoproterozoic and Archean rocks of the Indian cratonic interior and is 4 February 2018 either represented as metamorphosed sedimentary rocks of the Lesser Himalayan Sequence (LHS) or as Accepted 22 February 2018 slices of the distal cratonic margin. The other is the Greater Himalayan Sequence (GHS) whose prove- Available online 16 March 2018 nance is less clear and has an enigmatic affinity. -
Potassic “Adakite” Magmas and Where They Come From: a Mystery Solved? John Clemens Kingston University (London) Long Xiao China University of Geosciences (Wuhan)
1 Potassic “adakite” magmas and where they come from: a mystery solved? John Clemens Kingston University (London) Long Xiao China University of Geosciences (Wuhan) 2 3 4 . Adakites are volcanic and intrusive igneous rocks with 55 to 65 wt% SiO2, Al2O3 > 15 wt%, K2O/Na2O typically < 0.6, high La/Yb and Sr/Y ratios and strong depletion in Yb, Y, and HFSE. The name is from Adak island in the Alaskan Aleutians (Aleut “adak” = father). They are typically found in island and continental arc settings. Some believe then to be equivalents of Archæan TTG rocks – hence their importance. Their geochemical and isotopic characteristics suggest an origin by partial melting of mafic crust at pressures high enough to stabilise garnet and eliminate plagioclase. 5 . Adakites that occur in arcs have been interpreted as melts of the down-going slab. Thermal models suggest that slab melting should be restricted to young, hot subduction zones. Atherton and Petford (1993) suggested melting of young lower crustal rocks, in the upper plate, as an alternative to slab melting. There is some direct geological evidence for this alternative in some areas. 6 . Late Mesozoic granitoids in eastern China occur over wide areas, and lack either temporal or spatial association with subduction. Apart from their SiO2 contents, some have all the other geochemical attributes of typical subduction-related adakites, including a lack of Eu anomalies in their REE spectra, except that their K2O/Na2O > 0.95. This is possibly an erroneous attribution as “adakitic”. However this occurrence casts doubt on the assumption of a subduction-related origin for all adakitic magmas.