Proceedings of the International Conferences on Basement Tectonics – serie

The 7th International Conference on Basement Tectonics was held at Queen's University in Kingston, Ontario, Canada, from August 17th to 21st, 1987. Much ofthe conference was devoted to presentations and discussions on "Major Fracture Zones in the Earth's Crust" and "The Tectonic Evolution of North America" . Subsidiary themes at the conference were "Tectonic Controls of Cratonic Basins" and "Basement Structures and Metallogeny" . The conference was characterized by lively discussion amongst a diverse group of participants with a broad spectrum of interests, encouraged by the single-session format of the conference and a generous allotment of time for discussion following each presentation. The following presided over individual sessions and their assistance is greatly acknowledged: D.L. Baars, P.J. Barosh, M.J. Bartholomew, R.e. Bostrom, D.M. Carmichael, E.M. Chown, J.J. Gallagher, M.C. Gilbert, H. Helmstaedt, R.A. Hodgson, Y.O. Isachsen, J. Kutina, P.D. Lowman, S.P. Gay, Jr. and M.J. Rickard.

The Proceedings of the Eighth International Basement Tectonics Conference examines the tectonics of Mesozoic and older continental margins. Internationally recognized experts in a variety of fields - igneous and metamorphic petrology, geophysics, structural geology, metallogeny, geochronolgy - reviewed broad, key, integrative aspects of major fields that contribute to knowledge of the tectonics of margins. Many other presentations represented new, recently completed studies of specific areas or problems. The Penrose style of presentation ensured the cross-fertilization of interdisciplinary ideas within the constraints that one field superimposes on another. The introductory chapter deals with specific concepts, techniques, and ambiguities applicable to the tectonics of continental margins. An entire chapter is devoted to the relationship of metallogeny and continental margins with a major emphasis on the occurrence of gold.The tectonic development of many Archean, Proterozoic, and even Paleozoic orogenic belts is commonly obscure or poorly constrained because erosion or subsequent tectonism has often obliterated important tectonic 'keys' recorded in rocks of shallower crustal levels leaving only deeper crustal rocks juxtaposed. By comparison, a high degree of understanding has evolved regarding the complex tectonics (e.g. terrane accretion, development of metamorphic core complexes) of the convergent margin of the North American Cordillera. The second chapter is exclusively devoted to many superlative comparative aspects of the Cordilleran Mesozoic margin. Characterization of Precambrian margins, particularly of the North American craton, is the subject of another chapter. Aspects of the divergent margins of the late Proterozoic and Mesozoic Appalachian orogen, as well as its Paleozoic convergent margin, are described in a single chapter. Problems at margins in Europe, Asia, Africa and the circum-Pacific region are discussed in several chapters.

The 10th International Basement Tectonics Conference was conducted on the campus of the University of Minnesota, Duluth, in Duluth, Minnesota, USA, from August I through August 11, 1992. A total of 78 individuals were in attendance, 47 of which represented the host country, with the remaining 31 traveling from 11 different foreign countries. The four days of presentations were divided into three technical sessions, namely "Shear Zones", "Basement Control On Younger Structures", and "Rifting­ Midcontinent Rift System". This tripartite conference theme was also employed in the field trip agenda with three excursions being offered, all ably organized by Field Trip Chairman John C. Green. The pre-conference trip set the stage through a two day review of the "Archean and Early Proterozoic Rocks of Northeastern Minnesota". Under beautiful summer skies, 16 sites were visited within the Vermilion district of Minnesota, considered to be the best example of an Archean greenstone belt in the United States. All registrants participated in the mid-conference trip conducted along the gabbroic and volcanic terrain of the "Midcontinent Rift, Northeastern Minnesota".

The Eleventh International Conference on Basement Tectonics was held at the GeoForschungsZentrum Potsdam in Germany 25-29 July 1994. It was the first time that a meeting of this series took place in the centre of Europe and the first such meeting in this area after the recent political changes in eastern Europe. Consequently, the main theme of the meeting focussed on the structure and history of the entire European continent. Further themes were grouped around topics of current interest. Keynote lectures on these topics were given by A. Berthelsen, St. Mueller, A. Green, and D. Fountain. The technical sessions were arranged with support of the Scientific Committee on the following topics: 1. Continental scale features of basement rocks of phanerozoic cratons - with emphasis on Europe 2. Extrapolation and correlation of geological and geophysical data from basement rocks: an assessment 3. Mechanisms of basement exhumation in the evolution of orogenic belts 4. Structure and intraplate deformation of the North-American craton Papers submitted to this volume have however all been collected in one part since all of them deal with different aspects of deformation of the continental basement. A second part contains a complete list of all papers and posters presented at the meeting. Field trips to study some of the above mentioned aspects in the Harz mountains, the Granulite Massif, and the Erzgebirge were organized by P. Bankwitz, P. Frischbutter, 1. Rotzler, K. Rotzler, and B. Mingram. Their assistance is gratefully acknowledged.

The 12thInternational BasementTectonicsConferencewas hostedbythe Schoolof Geologyand Geophysics and theOklahoma Geological Survey inthe SarkeysEnergy Centeronthe campusoftheUniversityofOklahoma, Norman, Oklahoma, U. S. A. , from May 21stthroughMay 26th, 1995. Atotal of52 individualswere in attendance, 9 ofwhichwereattendingfrom 6differentforeign countries. Fourdaysoforal and posterpresentationswere divided intofour technical sessions withthefollowing themes: I)FractureDevelopment, Reactivation, andMineralization, organizedbyM. 1. Bartholomewand S. Marshak; 2)EvolutionoftheBasementofthe North American Plate (with special emphasison its southern margin), organizedby R E. Denisonand E. G. Lidiak; 3)ProbingofBasement: Geophysical and Geochemical Methods,organizedbyR A. Youngand G. R Keller; and 4)ResponseofCoverRocks toBasementDeformation, organized by P. Berendsenand M. P. Carlson. Seventy-five presentationswere made during thecourseofthe meeting, which wasorganizedby Program Chairman M. Charles Gilbertandprofessionally managedbySaraMoody.Precedingthe meeting wasatwo dayfield trip toexaminethe modeand kinematics ofterraneaccretion duringclosureofan oceanbasin, as preserved in thePrecambrian geologyoftheeasternLlano Uplift, Texas, U. S. A. Thefield trip leaders Sharon Mosher, MarkHelper, Don Barker, and Robert Reed providedan excellentand comprehensive guidebook, and shared theirconsiderable expertise in manydiscussions at one spectacularexposures afteranother. All registrants participatedinthe mid-conferencefield tripguidedby R E. Denison, E. G. Lidiak, M. C. Gilbert, and John P. Hogan to examinethePrecambrianand Cambrianbasementterranesexposed in the ArbuckleMountainsupliftin southernOklahoma, U. S. A. Evidencefor apossible continental arc settingfor the southern margin ofthe-1. 4 Ga Granite-Rhyolite Terrane, theopeningofthe Cambrian Southern Oklahoma Aulacogenasevidencedby aspectacularexposureofadiabasedike swarm, and the roleofearliertectonicfabrics in thedevelopmentofyoungerstructureswere someofthe topicsofdiscussion. Thetwo day postconferencefield trip to the WichitaMountains uplift, southwestern Oklahoma, U. S. A. was ledby M. Charles Gilbert, and John P. Hogan.Thistrip highlightedthe Cambrian SouthernOklahoma Aulacogen.

Comprising the proceedings of the Thirteenth International Basement Tectonics Conference, this collection of papers follows in the footsteps of earlier symposia in highlighting the recent status of geological and geophysical investigations in basement-dominated regions of the world. A significant number of papers deal with the tectonics of terranes - their transport, accretionary history and recognition. New petrologic, structural geochemical and geochronologic data from nine countries on four continents provide the framework for the interpretation of processes associated with basement tectonics. Topics range from structural, petrologic and isotopic interpretation of Grenville events to magmatism associated with rifting. Broader keynote papers deal with topics ranging from the geodynamics of the Early Precambrian to the identification of new tectonic belts in the Baltic Sea Region.

The 7th International Conference on Basement Tectonics was held at Queen's University in Kingston, Ontario, Canada, from August 17th to 21st, 1987. Much ofthe conference was devoted to presentations and discussions on "Major Fracture Zones in the Earth's Crust" and "The Tectonic Evolution of North America" . Subsidiary themes at the conference were "Tectonic Controls of Cratonic Basins" and "Basement Structures and Metallogeny" . The conference was characterized by lively discussion amongst a diverse group of participants with a broad spectrum of interests, encouraged by the single-session format of the conference and a generous allotment of time for discussion following each presentation. The following presided over individual sessions and their assistance is greatly acknowledged: D.L. Baars, P.J. Barosh, M.J. Bartholomew, R.e. Bostrom, D.M. Carmichael, E.M. Chown, J.J. Gallagher, M.C. Gilbert, H. Helmstaedt, R.A. Hodgson, Y.O. Isachsen, J. Kutina, P.D. Lowman, S.P. Gay, Jr. and M.J. Rickard.

The 10th International Basement Tectonics Conference was conducted on the campus of the University of Minnesota, Duluth, in Duluth, Minnesota, USA, from August I through August 11, 1992. A total of 78 individuals were in attendance, 47 of which represented the host country, with the remaining 31 traveling from 11 different foreign countries. The four days of presentations were divided into three technical sessions, namely "Shear Zones", "Basement Control On Younger Structures", and "Rifting­ Midcontinent Rift System". This tripartite conference theme was also employed in the field trip agenda with three excursions being offered, all ably organized by Field Trip Chairman John C. Green. The pre-conference trip set the stage through a two day review of the "Archean and Early Proterozoic Rocks of Northeastern Minnesota". Under beautiful summer skies, 16 sites were visited within the Vermilion district of Minnesota, considered to be the best example of an Archean greenstone belt in the United States. All registrants participated in the mid-conference trip conducted along the gabbroic and volcanic terrain of the "Midcontinent Rift, Northeastern Minnesota".

The 8th International Conference on Basement Tectonics was held in Butte, Montana, August 8-12,1988. Historically, basement tectonics conferences have focused on such topics as reactivation of faults, the influence of basement faults on metallogeny and hyrocarbon accumulation, and the use of geophysical and remote sensing techniques to interpret subsurface and surface geology. The 8th Conference diverged from past conferences in that a unifying theme was selected. Because ancient major terrane or cratonic boundaries are often postulated to be fault zones which are subsequently reactivated, the conference was organized to examine all aspects of ancient continental margins and terrane boundaries and to compare younger (Mesozoic) ones, about which more is known, with older (Paleozoic and Precambrian) ones. Moreover, because the 8th Conference was held in the northwestern United States, a greater emphasis was placed on the Mesozoic margin of western North America and the North American shield. The seven oral sessions and four poster sessions all dealt with aspects of the conference theme: characterization and comparison of ancient continental margins. The organizers extend their thanks to those individuals who graciously consented to serve as moderators for the oral sessions: John M. Bartley, Mark S. Gettings, M. Charles Gilbert, John M. Guilbert, Donald W. Hyndman, William P. Leeman, Robert Mason, and A. Krishna Sinha. The program with abstracts volume was prepared by S. E. Lewis and M. J. Bartholomew.

The Ninth International Conference on Basement Tectonics was held at the Australian National University in Canberra 2-6 July 1990. The opening keynote address was given by Prof. R.W.R. Rutland, Director of the Bureau of Mineral Resources. Other keynote speakers were E.S.T. O'Driscoll, an Australian consultant, and Prof P. Bankwitz, Central Institute for Physics of the Earth, Potsdam, GDR. Technical sessions were arranged by session conveners on the following five topic- i) The structure of the Australian craton and cover basins; ii) Basement structure of continental regions; iii) Structural patterns and mineral deposits; iv) Techniques for analysing basement structures; v) Structural patterns in oceanic crust. The arrangement of papers for this Proceedings Volume has been simplified. Part 1 deals with Australia, Part 2 with other areas and Part 3 lists the titles of all the papers read at the conference. Abstracts of these papers are available in Geological Society of Australia Abstracts No 26 and may be purchased for $AI0 from the Geological Society of Australia Office, ANA House, 301 George Street, Sydney NSW 2000. Field trips to view aspects of the Lachlan Fold Belt and the Sydney Basin were assisted by H.J. Harrington, D. Branagan, D. Wyborn, B. Drummond and M.J. Rick~d. A longer field trip, aborted through low enrolments, was organized by H.J. Harrington with assistance from W. Preiss, N. Cook, R. Glenn, A. Grady, and P. James; this assistance is gratefully acknowledged.

The Thirteenth International Conference on Basement Tectonics was held on the campus of Virginia Polytechnic Institute and State University in Blacksburg, Virginia from June 2 -6, 1997. The oral presentations and discussions over three days covered a wide range of topics, and provided the international audience with a perspective on scientific efforts underway around the world. The conference participants were able to attend two separate field trips: (I) a pre-conference trip guided by Professor Robert Hatcher of the University of Tennessee, Knoxville, examined the Basement rocks in the North Carolina -Tennessee region of the Appalachian Mountains, and (2) a mid-conference field trip guided by A.K. Sinha, convener of the conference, allowed participants to examine the complex rock associations and structures of the> 1000 m.y. old basement rocks in Virginia. Both the field trip guidebooks and abstract volumes were published for the conference. The meeting brought together scientists from more than 14 countries. Their participation, and the fiscal success of the meeting would not have been possible without the support of the Department of Geological Sciences, the College of Arts and Sciences (VPI&SU) and the Basement Tectonics Association. Their support is gratefully acknowledged. As Chairman of the Organizing Committee, I would like to thank Margie Sentelle, Jay Thomas, Peter Welch, and Barry Robinson for the smooth operation of the conference.

The 12thInternational BasementTectonicsConferencewas hostedbythe Schoolof Geologyand Geophysics and theOklahoma Geological Survey inthe SarkeysEnergy Centeronthe campusoftheUniversityofOklahoma, Norman, Oklahoma, U. S. A. , from May 21stthroughMay 26th, 1995. Atotal of52 individualswere in attendance, 9 ofwhichwereattendingfrom 6differentforeign countries. Fourdaysoforal and posterpresentationswere divided intofour technical sessions withthefollowing themes: I)FractureDevelopment, Reactivation, andMineralization, organizedbyM. 1. Bartholomewand S. Marshak; 2)EvolutionoftheBasementofthe North American Plate (with special emphasison its southern margin), organizedby R E. Denisonand E. G. Lidiak; 3)ProbingofBasement: Geophysical and Geochemical Methods,organizedbyR A. Youngand G. R Keller; and 4)ResponseofCoverRocks toBasementDeformation, organized by P. Berendsenand M. P. Carlson. Seventy-five presentationswere made during thecourseofthe meeting, which wasorganizedby Program Chairman M. Charles Gilbertandprofessionally managedbySaraMoody.Precedingthe meeting wasatwo dayfield trip toexaminethe modeand kinematics ofterraneaccretion duringclosureofan oceanbasin, as preserved in thePrecambrian geologyoftheeasternLlano Uplift, Texas, U. S. A. Thefield trip leaders Sharon Mosher, MarkHelper, Don Barker, and Robert Reed providedan excellentand comprehensive guidebook, and shared theirconsiderable expertise in manydiscussions at one spectacularexposures afteranother. All registrants participatedinthe mid-conferencefield tripguidedby R E. Denison, E. G. Lidiak, M. C. Gilbert, and John P. Hogan to examinethePrecambrianand Cambrianbasementterranesexposed in the ArbuckleMountainsupliftin southernOklahoma, U. S. A. Evidencefor apossible continental arc settingfor the southern margin ofthe-1. 4 Ga Granite-Rhyolite Terrane, theopeningofthe Cambrian Southern Oklahoma Aulacogenasevidencedby aspectacularexposureofadiabasedike swarm, and the roleofearliertectonicfabrics in thedevelopmentofyoungerstructureswere someofthe topicsofdiscussion. Thetwo day postconferencefield trip to the WichitaMountains uplift, southwestern Oklahoma, U. S. A. was ledby M. Charles Gilbert, and John P. Hogan.Thistrip highlightedthe Cambrian SouthernOklahoma Aulacogen.