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Geology and Geochemistry of the Southern Explorer Ridge Seafloor Hydrothermal Site Using an Integrated GIS Database and 3D Modeling

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Geology and Geochemistry of the Southern Explorer Ridge Seafloor Hydrothermal Site Using an Integrated GIS Database and 3D Modeling Physiology, Geology and Geochemistry of the Southern Explorer Ridge Seafloor Hydrothermal Site Using an Integrated GIS Database and 3D Modeling Yannick C. Beaudoin A thesis subrnitted in conformity with the requirements for the degree of Master of Science Graduate Department of Geology University of Toronto O March 2001 National Library Bibliothèque nationale If1 of Canada du Canada Acquisitions and Acquisitions et Bibliogmphic Sewices services bibliogrâphiques 395 Wellington Street 395. rue Wellington Ottawa ON K1A ON4 Ottawa ON K1A ON4 Canada Canada Yow Ne votro nlfémma Our fiie Notre réfdrenw The author has granted a non- L'auteur a accordé une licence non exclusive licence allowing the exciusive permettant à la National Lhrary of Canada to Bibliothèque nationale du Canada de reproduce, loan, distribute or sell reproduire, prêter, distribuer ou copies of this thesis in microform, vendre des copies de cette thèse sous paper or electronic formats. la forme de microfiche/film, de reproduction sur papier ou sur format électronique. The author retains ownership of the L'auteur conserve la propriété du copyright in this thesis. Neither the droit d'auteur qui protège cette thèse. thesis nor substantial extracts fkom it Ni la thèse ni des extraits substantiels may be printed or othe*se de celle-ci ne doivent être imprimes reproduced without the author's ou autrement reproduits sans son permission. autorisation. Physiology, Geology and Geochemistry of the Southern Explorer Ridge Seafloor Hydrothermal Site Using an Integrated GIS Database and 3D Modeling by Yannick Beaudoin in partial fulfillment of the requirements for the degree of Master's of Science, March 2001, Graduate Department of Geology, University of Toronto Southem Explorer Ridge (SER) is an anomalously-rate shallow, intemediate spreading ridge located 200 kilometers off the west Coast of Vancouver Island, Canada. It ranges in depth between 2600 and 1760 rneters. For the fist time, geological, geochemical and geophysical data collecred frorn 15 cruises to SER have been assembled in a GIS fownat. The distribution of published WTi ratios and Mg## values of basalt glass were plotted using GIS techniques. The variability of these geochemical parameters correlates with proximity to the axial dome and certain new ss well as previously publisheci structural and rnorphologicai features. Three-dimensional modeling of Seabeam bathymetry and SeaMARC sonar data has provided enhanced visualization of SER. Physimlogical features make SER comparable to an elongate seamount. Specific morphological characteristics indicate that summit trough formation and evolution at SER result from non-steady state processes. The author would f~stand foremost like to thank Dr. S. D. Scott for his support and encouragement. In addition, Dr. Scott provided me with incredible opportunities to work with various international research tearns both on-land and at sea. The latter opened my eyes even wider to the wonderful and inspiring world of marine science. Thank you to Dr. Larry Mayer for introducing me to the technology behind full-motion graphics modeling 1 am also grateful to Drs. E. T. C. Spooner and M. Gorton of my supervising comrnittee for their guidance and interest. Though my project was mostly computer related, they both took keen interest in its progress. A great thanks is due Dr. T. Pichler for setting me on the path of marine geology. He chose me as his assistant for research done in Papua New Guinea back in my undergraduate years. 1 haven't looked back since. Hats off to al1 the current and former students of the Scotiabank Marine Geology Laboratory. We had fun, we worked hard and we helped each other. Thanks. A special thanks to TF, KB and VN,amazing friends that heIped me move forward through it dl. Merci à mes parents pour leur support éternel. Sans vous je ne serai pas où je suis aujourd'hui. LIST OF CDROM APPENDICES CDROM 1 SER data: Part 1 MapInfo Workspaces CDROM 2 SER data: Part 2 CDROM 3 SER rnovies Part I CDROM 4 SER movies Part 2 CDROM 5 SER rno vies Part 3 Files of .exe format are self-executable compressed files using Winzip 8.0 CONTENTS Abstract ......................................................................................... i .. Acknowledgements ............................................................................ 11 ... List of CDROM appendices ..................................................................rn Introduction .................................................................................... 1 Chapter 1: Developing the SER GIs ..........................- ............................. 2 Introduction .......................................................................... -2 Base map ............................................................................. -3 Two-dimensional layered approach .................. - ............................. 7 Three-dimensional data modeling ................................ .. .............. -30 Full motion modeling ............................................................... -42 Chapter 2: Geology of the SER: Interpretations and Results ............................ 43# Introduction .......................................................................... -45 Observations.. ......................................................................... 48 Volcanic facies ....................................................................... -75 Discussion ............................................................................. -80 Conclusion ....................................................................................... 89 References ...................................................................................... -91 INTRODUCTION The melding of computer techno10~~and marine geoscience has taken large strides over the past 20 years. Cornputers have gone from being simple data collection tools to full-blown analytical and interpretive systems. Marine geoscience at the southem Explorer Ridge (SER) reached a climax fiom the rnid 1980s to the mid 1990s when a series of research cruises studied, mapped, photographed and sampled the area (CASM III, 1984; SCHISM, 1984; CASM V, 1985; GSCLDGO, 1985; CASM VI, 1986; CUROSS 1, 1987; CUROSS II, 1988, CanRDGE 1, 1991; CanFüDGE II, 1992; CanRTDGE III 1994; CanRIDGE IV 1995). This study used the latest in data visualization technology to integrate by means of a geograptiical information system (GIS) the geochernistry, photography, sonar imagery and structural data obtained from the various cruises. The result is an almost complete database dedicated to the SER. All that is rnissing are some additional geological observations made on the SCMSM biological cruises. This database has enabled a much broader-based analysis and modeling than was previousiy possible Leading to interpretations pertaining to the SER7sphysiography, structure, volcanic facies and axial trough formation and evolution. This project was accomplished using a Pentium III 500 MHz PC with 256MB of RAM with the latest in mapping software. Though the figures and maps included in the text version are adequate for interpretation and analysis, best resolution and versatility can only be achieved by examining the models on a computer. CD-ROMs included with this thesis provide access to al1 files used over the course of the project. CHAITER 1: DEVELOPING TBE SER GIS Introduction Recent advances in the development of GIS have had a si-@icant impact on the way seafloor geology is now being presented. Unlike land-based fieldwork, early seafloor research often had to resort to manual plotting of observations on simple bathymetric maps and with inadequate navigation. Modern sea technology can now produce unparaileled images of the seafloor using various methods of acoustic and other geophysical techniques which make it possible for geologists to produce detaiIed 20 and 3D projections of any site. In addition to the visual modeling, interactive databases can be created and linked to form a digital environment of seafloor study areas. GIS work, as applied to marine geology, can bnng together geochemistry, geophysics, bathymetry, sonar imagery, structure and any numbér of elements into one concise, CO-registeredsetting From pure science to industrial economic applications, such complete, versatile and expandable models are increasingly important research tools. This paper focuses on the creation of a GIS for the southem Explorer Ridge system (SERI, which lies 200 kilometers off the West coast of Vancouver Island, British Columbia. With nearly 20 years of accumulated data, this site was an excellent candidate for the application of cornputer modeling techniques and the development of an interactive digitd database. The first stage of the project involved the development of the 2 dimensional environment. The step-by-step outiine used to describe the creation of the SER GIS covers al1 aspects behind the integration of various data sets and Spes. This includes methods of geographicd correction for location sensitive data, the re-processing of certain types of data to fit the software requirements and the review of archived video and photographs used to describe the geology and physiology of the site. 2 The final stage of GIS application involved the static and kinematic 3 dimensional modeling of the study area. Although the avaiiable datasets are old, the visud models produced from them are sùll an important component of the final product. This chapter descnbes the procedures involved in creathg these
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