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Widenfalk, Lennart
Publications (10 of 26) Show all publications
Lundberg, A., Erixon, P., Widenfalk, L., Maurice, C., Eriksson, B. & Rönnbäck, B. (2006). Promotion of collaborative learning in sustainable development: Arena Global Resources (ed.). In: (Ed.), Ingrid Järnefelt (Ed.), Proceedings 2005: utvecklingskonferensen 16-18 november i Karlstad. Paper presented at Utvecklingskonferensen för högre utbildning : 16/11/2005 - 18/11/2005. : Luleå tekniska universitet
Open this publication in new window or tab >>Promotion of collaborative learning in sustainable development: Arena Global Resources
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2006 (English)In: Proceedings 2005: utvecklingskonferensen 16-18 november i Karlstad / [ed] Ingrid Järnefelt, Luleå tekniska universitet, 2006Conference paper, Published paper (Other academic)
Abstract [en]

In the Arena Global resources many exercises that designed to promote team-work and collaborative learning were introduced during the first semester. Examples of exercises were: a) adventure based experiential learning b) supervised peer review of written (process writing) and oral student presentations c) an exercise that revealed the disadvantages with lack of co-operation d) a home-work exercise where the students were encouraged to co-operate e) team-work dealing with water resources in an international perspective f) student panel discussion where knowledge from two different courses was integrated g) a tree-day study tour where the students learn to know each other. The students were also encouraged to read texts describing advantages with collaborative learning.

Place, publisher, year, edition, pages
Luleå tekniska universitet, 2006
National Category
Geochemistry Pedagogy
Research subject
Applied Geology; Education
Identifiers
urn:nbn:se:ltu:diva-37814 (URN)bf2d44d0-10f1-11dc-95f3-000ea68e967b (Local ID)91-631-8772-8 (ISBN)bf2d44d0-10f1-11dc-95f3-000ea68e967b (Archive number)bf2d44d0-10f1-11dc-95f3-000ea68e967b (OAI)
Conference
Utvecklingskonferensen för högre utbildning : 16/11/2005 - 18/11/2005
Note
Godkänd; 2006; 20070602 (ysko)Available from: 2016-10-03 Created: 2016-10-03 Last updated: 2017-11-25Bibliographically approved
Rona, P., Murton, B., Boström, K., Widenfalk, L., Melson, W., O'Hearn, T., . . . Jenkins, W. (2005). Carslberg ridge and mid-atlantic ridge: slow-spreading apparent analogs (ed.). In: (Ed.), (Ed.), AGU, Fall Meeting: 5-9 December 2005, San Francisco, California. Paper presented at American Geophysical Union. 2005 Fall meeting : 05/12/2005 - 09/12/2005. : American Geophysical Union (AGU)
Open this publication in new window or tab >>Carslberg ridge and mid-atlantic ridge: slow-spreading apparent analogs
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2005 (English)In: AGU, Fall Meeting: 5-9 December 2005, San Francisco, California, American Geophysical Union (AGU), 2005Conference paper, Meeting abstract (Other academic)
Abstract [en]

We compare morphology, tectonics, petrology, and hydrothermal activity of a known section of the Mid-Atlantic Ridge (MAR) between the Kane and Atlantis fracture zones (full multi-beam coverage 21N to 31N) to the lesser known Carlsberg Ridge (CR; limited multi-beam coverage plus satellite altimetry). The CR extends from the Owen Fracture Zone (10N) to the Vityaz Fracture Zone (5S) and spreads at half-rates (~1.2-1.8 cm/yr) similar to the MAR: 1) Morphology: Both ridges exhibit distinct segmentation (primarily sinistral) and axial valleys with high floor to crest relief (range 1122-1771 m). Average lengths of segments (CR: 70 km; MAR: 50 km) and crest-to crest width of the axial valley are greater on the CR (40 km) than MAR (23 km). Axial volcanic ridges form the neovolcanic zone on both ridges, typically 2.6 km wide and 213 m high on the CR. Average water depth near segment centers is greater on the MAR (3933 m) than the CR (3564 m). V-shaped patterns oblique to the spreading axis are present on both ridges. 2) Tectonics: Segments on each ridge are predominantly separated by short-offset (<30 km) non-transform discontinuities with longer transform faults generally spaced hundreds of kilometers apart. Bulls-eye Mantle Bouguer Lows (-30 to -50 mgal) are present at centers of spreading segments on both ridges. Metamorphic core complexes of lower crust and upper mantle are present on the MAR section (at fracture zones) and at least at one locality at 58.33E on the CR. 3) Petrology: MORB composition from our 20 stations along the CR fall into the MORB family, with no evidence of hotspot inputs (no excess K or Nb), or extreme fractionation, similar to the MAR section. REE and trace element patterns between 57E and 61E on the CR indicate increasing melt depletion to the northwest, while glasses exhibit a striking systematic increase in MgO (decrease in fractionation) to the northwest and attain among the most primitive composition of any ocean ridge adjacent to the Owen fracture zone (9.93wt percent). Sr, Nd, and Pb isotopic compositions of Indian Ocean MORB are distinct from those of other oceans. They exhibit relatively higher 87Sr/86Sr, and lower 143Nd/144Nd, 207Pb/204Pb and 208Pb/204Pb for a given 206Pb/204Pb invoking mixing and regional-scale contamination of a depleted mantle with a variously designated enriched reservoir (EM1, EM2, DUPAL, etc.). 4) Hydrothermal activity: The MAR section encompasses a low-T hydrothermal field driven by the serpentinization at the Atlantis fracture zone (Lost City at 30N), and three high-temperature fields driven by magmatic heat in the axial valley (Broken Spur 29N, TAG 26N, and Snake Pit 23N). A 70 km-long, 1000 m-thick megaplume was detected in the water column up to 1400 m above the CR axial valley centered at 6.05N, 60.95E in August 2003, the first clear evidence of high-temperature hydrothermal activity on the CR. Further CR hydrothermal evidence includes relict sulfide chimneys at 58E; Mn-oxide coatings on basalts in the axial valley with Fe/Mn ratios at the boundary between hydrogenous and hydrothermal composition with thickness at two stations (1.67S, 67.77E; 5.35S, 68.62E) suggestive of hydrothermal input; and a d3He anomaly (166 per mil) in the water column at one of our stations in April 1979 (5.35S, 68.62E).

Place, publisher, year, edition, pages
American Geophysical Union (AGU), 2005
National Category
Geology
Research subject
Ore Geology
Identifiers
urn:nbn:se:ltu:diva-40385 (URN)f7a12970-146c-11dc-b9f0-000ea68e967b (Local ID)f7a12970-146c-11dc-b9f0-000ea68e967b (Archive number)f7a12970-146c-11dc-b9f0-000ea68e967b (OAI)
Conference
American Geophysical Union. 2005 Fall meeting : 05/12/2005 - 09/12/2005
Note
Godkänd; 2005; 20070606 (ysko)Available from: 2016-10-03 Created: 2016-10-03 Last updated: 2017-11-25Bibliographically approved
Sterner, R. & Widenfalk, L. (2004). Engineering on precious stones and metals: distance education enables cooperation of university, society and industry in rural areas (ed.). In: (Ed.), Andras Szucs; Ingeborg Bø (Ed.), New challenges and partnerships in an enlarged European Union - open, distance and e-Learning in support of modernisation, capacity building and regional development: proceedings of the EDEN 2004 Annual Conference - Budapest, Hungary. Paper presented at EDEN Conference : 16/06/2004 - 19/06/2004 (pp. 247-250). Budapest: European Distance and e-learning Network
Open this publication in new window or tab >>Engineering on precious stones and metals: distance education enables cooperation of university, society and industry in rural areas
2004 (English)In: New challenges and partnerships in an enlarged European Union - open, distance and e-Learning in support of modernisation, capacity building and regional development: proceedings of the EDEN 2004 Annual Conference - Budapest, Hungary / [ed] Andras Szucs; Ingeborg Bø, Budapest: European Distance and e-learning Network , 2004, p. 247-250Conference paper, Published paper (Refereed)
Place, publisher, year, edition, pages
Budapest: European Distance and e-learning Network, 2004
National Category
Geology
Research subject
Ore Geology
Identifiers
urn:nbn:se:ltu:diva-30539 (URN)4638e320-c1bb-11db-9ea3-000ea68e967b (Local ID)4638e320-c1bb-11db-9ea3-000ea68e967b (Archive number)4638e320-c1bb-11db-9ea3-000ea68e967b (OAI)
Conference
EDEN Conference : 16/06/2004 - 19/06/2004
Note
Godkänd; 2004; 20061212 (ysko)Available from: 2016-09-30 Created: 2016-09-30 Last updated: 2017-11-25Bibliographically approved
Elming, S.-å., Widenfalk, L. & Rodriguez, D. (Eds.). (1998). Geoscientific research in Nicaragua: a Swedish-Nicaraguan joint project during the period 1981-1991 (ed.). Paper presented at . Luleå: Luleå tekniska universitet
Open this publication in new window or tab >>Geoscientific research in Nicaragua: a Swedish-Nicaraguan joint project during the period 1981-1991
1998 (English)Collection (editor) (Other academic)
Place, publisher, year, edition, pages
Luleå: Luleå tekniska universitet, 1998. p. 340
National Category
Geology Geophysics
Research subject
Ore Geology; Applied Geophysics
Identifiers
urn:nbn:se:ltu:diva-21647 (URN)7a5c4a30-ad4c-11db-905c-000ea68e967b (Local ID)7a5c4a30-ad4c-11db-905c-000ea68e967b (Archive number)7a5c4a30-ad4c-11db-905c-000ea68e967b (OAI)
Note
Godkänd; 1998; 20070126 (agso)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2017-11-24Bibliographically approved
Stephens, M. B., Halenius, U. & Widenfalk, L. (1996). A group of papers devoted to the geology of two paleoproterozoic base metal sulfide and gold mining districts in the Baltic shield, Sweden: preface (ed.). Paper presented at . Economic geology and the bulletin of the Society of Economic Geologists, 91(6), 977-978
Open this publication in new window or tab >>A group of papers devoted to the geology of two paleoproterozoic base metal sulfide and gold mining districts in the Baltic shield, Sweden: preface
1996 (English)In: Economic geology and the bulletin of the Society of Economic Geologists, ISSN 0361-0128, E-ISSN 1554-0774, Vol. 91, no 6, p. 977-978Article in journal, Editorial material (Other academic) Published
National Category
Geology
Research subject
Ore Geology
Identifiers
urn:nbn:se:ltu:diva-11019 (URN)9e923310-b0ba-11dd-9c9d-000ea68e967b (Local ID)9e923310-b0ba-11dd-9c9d-000ea68e967b (Archive number)9e923310-b0ba-11dd-9c9d-000ea68e967b (OAI)
Note
Godkänd; 1996; 20081112 (andbra)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2017-11-24Bibliographically approved
Skiöld, T., Öhlander, B., Markkula, H., Widenfalk, L. & Claesson, L.-Å. (1993). Chronology of Proterozoic orogenic processes at the Archaean continental margin in northern Sweden (ed.). Paper presented at . Precambrian Research, 64(1-4), 225-238
Open this publication in new window or tab >>Chronology of Proterozoic orogenic processes at the Archaean continental margin in northern Sweden
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1993 (English)In: Precambrian Research, ISSN 0301-9268, E-ISSN 1872-7433, Vol. 64, no 1-4, p. 225-238Article in journal (Refereed) Published
Abstract [en]

The Proterozoic Svecofennian orogeny was characterized by the rapid formation of great amounts of juvenile continental crust and extensive remobilization of older crust. This paper considers U---Pb zircon ages and some geochemical and lithostratigraphic features of the Svecofennian in the continental-margin area between the Skellefte ore district and the boundary of the Archaean craton farther north in Sweden. New U---Pb zircon ages constrain the igneous activity of Svecofennian crust formation in northern Sweden to between 1930 and 1870 Ma ago. The same time constraints apply also to crust formation farther east in Finland. Orogeny along the entire Archaean-Proterozoic boundary zone was thus simultaneous and does not represent an east-to-west event succession. It is argued that rocks with similar major element compositions but distinctly different trace element characteristics were formed simultaneously but in different plate-tectonic environments. By ≈ 1875 Ma ago, the Svecofennian volcanic arc had matured and a variety of syn- to late-orogenic igneous rocks appeared in both tensional and compressional settings. Shortly thereafter, the Svecofennian magmatic activity ceased altogether, probably as a result of collision between the arc and the Archaean continent in the north. It is also suggested that pre-Svecofennian rifting of the Archaean craton had created a passive continental margin and that the transition to an active margin with subsequent island-arc magmatism and subduction beneath the Archaean craton commenced prior to 1930 Ma ago. It may well have been initiated by a relative drift of the Archaean craton towards the present southwest as a consequence of the formation of the collisional Proterozoic Lapland Granulite Belt in the northernmost Baltic Shield.

National Category
Geochemistry Geology
Research subject
Applied Geology; Ore Geology
Identifiers
urn:nbn:se:ltu:diva-9665 (URN)10.1016/0301-9268(93)90078-G (DOI)A1993MT85500014 ()2-s2.0-0027832933 (Scopus ID)8551bba0-dd2b-11db-9cae-000ea68e967b (Local ID)8551bba0-dd2b-11db-9cae-000ea68e967b (Archive number)8551bba0-dd2b-11db-9cae-000ea68e967b (OAI)
Note
Godkänd; 1993; 20070328 (pafi)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Widenfalk, L. (1993). Ore formation and geology of the northern, central part of the Skellefte field, N. Sweden (ed.). In: (Ed.), Jan-Anders Perdahl (Ed.), Abstracts of lectures and posters: 21:a Nordiska geologiska vintermötet 10-13 Januari 1994 Luleå. Paper presented at Nordiska geologiska vintermötet : 10/01/1994 - 13/01/1994 (pp. 225). Luleå: Högskolan i Luleå
Open this publication in new window or tab >>Ore formation and geology of the northern, central part of the Skellefte field, N. Sweden
1993 (English)In: Abstracts of lectures and posters: 21:a Nordiska geologiska vintermötet 10-13 Januari 1994 Luleå / [ed] Jan-Anders Perdahl, Luleå: Högskolan i Luleå , 1993, p. 225-Conference paper, Meeting abstract (Other academic)
Place, publisher, year, edition, pages
Luleå: Högskolan i Luleå, 1993
National Category
Geology
Research subject
Ore Geology
Identifiers
urn:nbn:se:ltu:diva-31407 (URN)593a6160-f2ba-11dd-a323-000ea68e967b (Local ID)593a6160-f2ba-11dd-a323-000ea68e967b (Archive number)593a6160-f2ba-11dd-a323-000ea68e967b (OAI)
Conference
Nordiska geologiska vintermötet : 10/01/1994 - 13/01/1994
Note
Godkänd; 1993; 20090204 (andbra)Available from: 2016-09-30 Created: 2016-09-30 Last updated: 2017-11-25Bibliographically approved
Wolde, B. & Widenfalk, L. (1993). Petrological and geochemical constraints on cenozoic magnatism in Ethiopia (ed.). In: (Ed.), Jan-Anders Perdahl (Ed.), Abstracts of lectures and posters: 21:a Nordiska geologiska vintermötet 10-13 Januari 1994 Luleå. Paper presented at Nordiska geologiska vintermötet : 10/01/1994 - 13/01/1994 (pp. 229). Luleå: Högskolan i Luleå
Open this publication in new window or tab >>Petrological and geochemical constraints on cenozoic magnatism in Ethiopia
1993 (English)In: Abstracts of lectures and posters: 21:a Nordiska geologiska vintermötet 10-13 Januari 1994 Luleå / [ed] Jan-Anders Perdahl, Luleå: Högskolan i Luleå , 1993, p. 229-Conference paper (Other academic)
Place, publisher, year, edition, pages
Luleå: Högskolan i Luleå, 1993
National Category
Geology
Research subject
Ore Geology
Identifiers
urn:nbn:se:ltu:diva-35546 (URN)a1df1cb0-f2bc-11dd-a323-000ea68e967b (Local ID)a1df1cb0-f2bc-11dd-a323-000ea68e967b (Archive number)a1df1cb0-f2bc-11dd-a323-000ea68e967b (OAI)
Conference
Nordiska geologiska vintermötet : 10/01/1994 - 13/01/1994
Note

Godkänd; 1993; 20090204 (andbra)

Available from: 2016-09-30 Created: 2016-09-30 Last updated: 2018-02-08Bibliographically approved
Widenfalk, L. & Forsberg, L.-O. (1993). PIM - ore geology related to exploration: a national programme (ed.). In: (Ed.), Jan-Anders Perdahl (Ed.), Abstracts of lectures and posters: 21:a Nordiska geologiska vintermötet 10-13 Januari 1994 Luleå. Paper presented at Nordiska geologiska vintermötet : 10/01/1994 - 13/01/1994 (pp. 226). Luleå: Högskolan i Luleå
Open this publication in new window or tab >>PIM - ore geology related to exploration: a national programme
1993 (English)In: Abstracts of lectures and posters: 21:a Nordiska geologiska vintermötet 10-13 Januari 1994 Luleå / [ed] Jan-Anders Perdahl, Luleå: Högskolan i Luleå , 1993, p. 226-Conference paper, Meeting abstract (Other academic)
Place, publisher, year, edition, pages
Luleå: Högskolan i Luleå, 1993
National Category
Geology
Research subject
Ore Geology
Identifiers
urn:nbn:se:ltu:diva-29447 (URN)2ee1d0a0-f2bb-11dd-a323-000ea68e967b (Local ID)2ee1d0a0-f2bb-11dd-a323-000ea68e967b (Archive number)2ee1d0a0-f2bb-11dd-a323-000ea68e967b (OAI)
Conference
Nordiska geologiska vintermötet : 10/01/1994 - 13/01/1994
Note
Godkänd; 1993; 20090204 (andbra)Available from: 2016-09-30 Created: 2016-09-30 Last updated: 2017-11-25Bibliographically approved
Wolde, B. & Widenfalk, L. (1993). The petrology and geochemistry of Ethiopian plateau and rift basalts: Part I, Oligocene and upper Miocene tholeiites (ed.). Paper presented at European Union of Geosciences : 04/04/1993 - 08/04/1993. , 5(Suppl. 1), 540
Open this publication in new window or tab >>The petrology and geochemistry of Ethiopian plateau and rift basalts: Part I, Oligocene and upper Miocene tholeiites
1993 (English)In: Vol. 5, no Suppl. 1, p. 540-Article in journal, Meeting abstract (Other academic) Published
National Category
Geology
Research subject
Ore Geology
Identifiers
urn:nbn:se:ltu:diva-34602 (URN)8d7acf50-0016-11de-a8bd-000ea68e967b (Local ID)8d7acf50-0016-11de-a8bd-000ea68e967b (Archive number)8d7acf50-0016-11de-a8bd-000ea68e967b (OAI)
Conference
European Union of Geosciences : 04/04/1993 - 08/04/1993
Note

Godkänd; 1993; Bibliografisk uppgift: Volumne: 5; 20090221 (ysko)

Available from: 2016-09-30 Created: 2016-09-30 Last updated: 2018-02-08Bibliographically approved
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