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.

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.