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Utilization of a large geochemical-geochronologic database to determine the paternity and wanderings of orphaned conglomerate clasts in the Gualala Basin, California; implications for provenance studies and tectonic reconstructions in the North American Cordillera.
AUTHORS: Schott-Ronald-C
BOOK TITLE: In: Geological Society of America, Rocky Mountain Section, 56th annual meeting; Geological Society of America, Cordilleran Section, 100th annual meeting.
BOOK AUTHORS: Anonymous
SOURCE: Abstracts with Programs - Geological Society of America. 36; 4, Pages 10. 2004.
PUBLICATION YEAR: 2004
ABSTRACT: Late Cretaceous and Paleogene conglomerates currently located in the Gualala Basin of coastal northern California have no local bedrock sources and have been displaced by at least hundreds of kilometers from their site of deposition by the San Andreas fault system. Paleomagnetic and paleontologic studies have suggested an origin as far south as Baja California. Additionally, the timing of conglomerate sedimentation and the basin's palinspastically restored position prior to Neogene San Andreas system offsets allow for the possibility of conglomerate provenance in the hypothesized "Baja BC" Terrane as it migrated northward. In order to discriminate between the wide range of potential conglomerate provenance terranes, a large database was compiled, containing published geologic, geochemical, isotopic, and geochronological data for igneous rocks from throughout the Mesozoic Cordilleran magmatic arcs. Comparison of geochemical and isotopic data from Gualala conglomerates with the large Cordilleran dataset enabled definitive exclusion of some hypothesized source terranes. Moreover, although no single clast type in this study was able to be uniquely matched to a source pluton to form a "piercing point", comparison of the full datasets was instrumental in narrowing the most likely source terrane for the Gualala clasts to the formerly contiguous southwestern Sierra-northern Salinian-western Mojave region. The Mesozoic Cordilleran dataset (mostly plutonic rocks) compiled for this study is currently being added to the NAVDAT database and has potential to be utilized by future provenance studies in the Cordilleran region.
In Database: GeoRef : 2002-2004/12.
Time-animated geochemical variation diagrams as a tool for exploring large datasets.
AUTHORS: Roelofs-Austin; Mapes-Russell-W; Glazner-Allen-F
BOOK TITLE:In: Geological Society of America, Rocky Mountain Section, 56th annual meeting; Geological Society of America, Cordilleran Section, 100th annual meeting.
BOOK AUTHORS: Anonymous
SOURCE: Abstracts with Programs - Geological Society of America. 36; 4, Pages 10. 2004.
PUBLICATION YEAR: 2004
ABSTRACT: Animations of the large datasets available in geochemical databases such as NAVDAT can illuminate new spatial and temporal trends. Commonly, geochemical data are plotted for large areas over large time spans on a single diagram or on a few paneled time slices. Although large-scale patterns can be perceived through such portrayals, the details of subtle transitions or sudden changes are commonly missed. Animating geochemical variation diagrams and the locations of events side by side over small time intervals make spatial and temporal trends in chemistry easier to interpret. Geochemical data drawn from NAVDAT have been time-animated in a number of ways to reveal interesting trends in magmatism of the Western U.S. One example, an animated K (sub 2) O-SiO (sub 2) variation diagram for samples from eastern California and west-central Nevada, shows magma compositions changing from silicic and high-K to more mafic low- and intermediate-K over the interval 10-5 Ma, followed by a pulse of high-K mafic magmatism associated with the 3.5 Ma delamination(?) event. An animated total alkalis-silica volcanic classification diagram of rocks from the same area shows that they are distributed somewhat evenly across the range of rock types from 10-3 Ma, then separate into bimodal basaltic and rhyodacitic populations from 3 Ma to the present. In a third example, we evaluated the conclusion of Ormerod et al. (1988) that the Zr/Ba ratio in late Cenozoic basalts of the western Great Basin changes in concert with a transition in magmatism from basalts derived above a subduction zone to basalts derived from the convecting upper mantle following the south-to-north passage of the trailing edge of the subducting slab. Time-animation of a NAVDAT dataset incorporating six recent studies agrees with their south-to-north migration model. Time-animation of geochemical variation makes interpretation of otherwise cumbersome datasets easier by putting them in a temporal context. User control over animations increases understanding of the dataset. The greater resolution of time-animations will become increasingly important in interpretation as the amount of information contained in databases such as NAVDAT grows.
In Database: GeoRef : 2002-2004/12.
Animation of space-time trends in Cenozoic magmatism of western North America.
AUTHORS: Glazner-Allen-F
BOOK TITLE: In: Geological Society of America, Rocky Mountain Section, 56th annual meeting; Geological Society of America, Cordilleran Section, 100th annual meeting.
BOOK AUTHORS: Anonymous
SOURCE: Abstracts with Programs - Geological Society of America. 36; 4, Pages 10. 2004.
PUBLICATION YEAR: 2004
ABSTRACT: Animation provides a powerful tool for discovering space-time patterns in magmatism, far more powerful than the static 2-dimensional time slices that can be portrayed on paper. Magmatic history has long been used to decipher the rich history of plate interaction along the west coast of North America, and animation of the NAVDAT dataset discloses several new and enigmatic patterns. NAVDAT (navdat.geo.ku.edu; see also earthchem.org) is a growing database of geochronologic and geochemical data on Cenozoic magmatism in western North America. This paper discusses Western U.S. data in NAVDAT (currently about 6500 fully attributed analyses) and existing geochronologic databases from the USGS and the New Mexico, Arizona, and Nevada state surveys. Relevant animations are posted at the NAVDAT site. Several first-order patterns are apparent in the animations, including: (1) A strong sweep starting in Montana approximately 55 Ma and moving rapidly southwestward into the Great Basin. This sweep enlarged to a wide band stretching from eastern California to western Utah approximately 27 Ma and then slowly moved southward to southern Nevada approximately 15 Ma. (2) A clockwise sweep around the Colorado Plateau, starting in southwestern New Mexico approximately 30 Ma and also ending in southern Nevada approximately 15 Ma. (3) A burst of magmatism in northern Nevada approximately 15 Ma that spread outward to Yellowstone, the central Sierra Nevada, and central Oregon. (4) Waves that converged in the Quaternary on the High Cascades from the west (slowly) and east (rapidly). (5) A Pliocene outburst in eastern California. (6) Several more local northward migrations, including late Cenozoic movements through the San Francisco Bay area and along the southern Wasatch Front, and Miocene-Recent movement through Phoenix to the San Francisco Peaks of Arizona. The patterns displayed by these animations are clearly migratory at several scales, but it is difficult to tie them to simple models of plate interaction. Patterns that could be related to shallowing and steepening of the Farallon Plate or to developing slab windows are not obvious. The "splash" of magmatism in the northern Great Basin is consistent with impingement of a Yellowstone plume head. The strongest pattern of all, the southwestward sweep of magmatism from Montana to Nevada, runs counter to plate motion.
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In Database: GeoRef : 2002-2004/12.
Creation of a North American volcanic and plutonic rock database (NAVDAT).
AUTHORS: Walker-J-Douglas; Bowers-Todd-D; Glazner-Allen-F; Farmer-G-Lang; Carlson-Richard-W
BOOK TITLE: In: Geological Society of America, Rocky Mountain Section, 56th annual meeting; Geological Society of America, Cordilleran Section, 100th annual meeting.
BOOK AUTHORS: Anonymous
SOURCE: Abstracts with Programs - Geological Society of America. 36; 4, Pages 9. 2004.
PUBLICATION YEAR: 2004
ABSTRACT: We are compiling NAVDAT, a database of geochemical and age information for Cenozoic igneous rocks in western North America. NAVDAT will allow unprecedented exploration of temporal and spatial patterns in igneous activity and will allow investigators to correlate these patterns with local and regional tectonic development and lithospheric structure. The database is web-accessible for downloads and queries (navdat.geo.ku.edu--soon to be part of the GEON Grid). Allied information, such as geologic and geophysical maps, crustal structure, etc., are or will also be available through a map interface. We are collaborating with other igneous database efforts, PetDB and GEOROC (petdb.ldeo.columbia.edu, georoc.mpch-mainz.gwdg.de), in order to develop compatible schema and to build consensus on an overall database structure. The three efforts have a common entry point at earthchem.org. Work to date has included developing the data entry method and relational database structure and archiving legacy data from published papers and theses. In addition we have search routines working and plots of rock data as Harker diagrams, element-normalization diagrams, and on state map outlines. We are currently working at plotting data onto state and North American geologic maps. Samples are linked to GeoRef information for papers and theses. Some preliminary results from NAVDAT are posted at navdat.geo.ku.edu, which shows a variety of graphical products produced from the data now in the database. Of particular interest is the animation of magmatism in the western U.S. over the past 65 m.y. In addition the compilation shows the general evolution of igneous rocks to alkalic and bimodal compositions with time.
In Database: GeoRef : 2002-2004/12.
EarthChem.org; integrating data management for igneous geochemistry.
AUTHORS: Lehnert-Kerstin-A; Carlson-Richard-W; Hofmann-Albrecht; Langmuir-Charles-H; Lenhardt-W-Christopher; Sarbas-Baerbel; Walker-Douglas; Glazner-Allen; Farmer-Lang
BOOK TITLE: In: Geological Society of America, 2003 annual meeting.
BOOK AUTHORS: Anonymous
SOURCE: Abstracts with Programs - Geological Society of America. 35; 6, Pages 366. 2003.
PUBLICATION YEAR: 2003
ABSTRACT: Geochemical data for igneous rocks and minerals are an intrinsic part of the diverse data set that is needed to shape and improve our understanding of Earth characteristics, processes and evolution. Until a few years ago, utilization of geochemical data was impeded by the lack of easily accessible, comprehensive data compilations. GEOROC, NAVDAT and PetDB are three independent database efforts that have dramatically advanced management and accessibility of geochemical data by producing relational databases for igneous rock geochemistry--each one with its own sub-disciplinary goal--with interactive on-line access to their data sets. Collaboration between the projects has ensured that the individual databases employ a similar data schema leading to exemplary cross database compatibility. EarthChem (http://www.earthchem.org) showcases the combined effort of these databases to create an integrated information system for rock geochemistry. Addressing some of the challenges that the development of an integrated cyber infrastructure for the Geosciences presents, EarthChem will focus its activities on (1) archiving legacy data, (2) developing a system that will guarantee correct and comprehensive reporting of future data and that will allow rapid dissemination of new data through dynamic population of the databases, (3) ensuring cross database compatibility that will promote closer cooperation and easier integration with broader pan-Geoscience information technology developments (GEON, CHRONOS, ISES-CI, ISS, GERM), (4) developing analytical tools for using the geochemical data in geochemical, petrological and geological applications.
In Database: GeoRef : 2002-2004/12.
NAVDAT; a western North American volcanic and intrusive rock geochemical database.
AUTHORS: Carlson-Richard-W; Walker-Douglas; Black-Ross; Glazner-Allen; Farmer-Lang; Grossman-Jeffrey
BOOK TITLE: In: Geological Society of America, 2001 annual meeting.
BOOK AUTHORS: Anonymous
SOURCE: Abstracts with Programs - Geological Society of America. 33; 6, Pages 175. 2001.
PUBLICATION YEAR: 2001
ABSTRACT: At present there is no generally accessible geochemical database for Mesozoic and younger volcanic rocks in North America, despite the proliferation of high quality age, chemical and isotopic studies of these rocks over the last 15-20 years. As a result, it is not currently possible to extract from the existing volcanic rock data the regional patterns in the age, compositions, and sources of western North American magmatism that would allow assessment of how volcanism relates to the overall Cenozoic geologic evolution of western North America. With support from the NSF-IT program and DOD-China Lake, we are initiating a two-year project to compile existing age, chemical, and isotopic data from Late Cretaceous to Holocene extrusive and intrusive igneous rocks from the western U.S., British Columbia, and northern Mexico into a web-accessible electronic database. The resultant product, the Western North America Volcanic and Intrusive Rock Database-NAVDAT, will be integrated into a geographic information system (GIS) to allow visualization of complex age-compositional patterns in volcanism throughout the study region. We will also develop any necessary relational and graphical tools to allow users of the database to address a wide variety of issues concerning the geologic evolution and present volcanic state of the western U.S. We anticipate that NAVDAT will yield fundamental insights into the role of changing plate orientations, mantle plumes, and lithospheric deformation in controlling the production, distribution, sources and composition of magmatism in the western U.S. and so provide a basis for general models of continental magmatism worldwide. The database will also provide a means of further investigating the origin of local volcanic centers in the western U.S. by allowing these centers to be rigorously assessed in terms of regional trends in the position, age and composition of magmatism. Finally, NAVDAT will provide the background database necessary for clearly identifying targets for additional studies of igneous rocks in the western U.S. and for archiving new data generated by these studies. Community input from both the data supply side and suggestions for features that would make NAVDAT useful to a broad community are most welcome.
In Database: GeoRef : 2002-2004/12.
Last update 2/25/2006
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