PGAP Home Permian Jurassic Movies, Slideshows and Maps Publications Recent Abstracts (full text) PGAP Activities Links

DATABASES, MAPS AND RECONSTRUCTION PROGRAMS


1. Our Plate Reconstruction Program, applicable to any interval in the last 300 million years, and our software package,
Paleogeographic Mapping Tools, are designed to run on a Silicon Graphics workstation. The continental orientations are based on original "fits" of the individual Linear Magnetic Anomalies of the ocean basins, and on a new statistical treatment of the paleomagnetic pole predictions. A reassignment of the geologic ages of the input pole determinations for the Carboniferous, Permian and Triassic has been made to improve the precision of these data. Paleogeographic data (in present-day coordinates) can be read in and easily plotted on these reconstructions and projected in a variety of orientations. We have recently made a move to Arcview, the geographic information system software from ESRI. We have implemented Arcview on our Macintosh, Wintel, and SGI (Unix) platforms and have begun the development of an add-on to Arcview that will allow all aspects of our work to be integrated within Arcview.

2. Detailed paleotopographic and paleobathymetric maps have been completed for a number of time intervals (4 Permian, 2 Jurassic and 1 Cretaceous) and more will be available in 2000. These maps are based on our own lithofacies data as well as an extensive compilation of published paleogeographic maps. Some oil companies have made direct use of this literature compilation, although most rely on our original interpretations.

3. Our main Lithofacies Database currently has 44,437 locality entries (e.g. Figure 6) which are distributed among 16 stage-length map intervals (2 Triassic, 3 Jurassic, 5 Cretaceous, 4 Tertiary, and 2 Quaternary). Each entry includes up to five lithofacies types, selected from 24 possible sedimentary and volcanic categories, as well as an assessment of the depositional environment and the literature citation. This database was assembled in the 1980's and continues to be edited and updated from time to time. In fact last summer we undertook a significant overhaul of this database including removal of more duplicates, completion of the linkage of each lithologic record with its appropriate PAPeRS reference (see below) and transfer of the database to a Wintel platform running under the Microsoft Access database manager. We are still new to Access and have not yet developed the same level as with the Macintosh based Helix Express Database manager but will continue to improve the interface and ease of use of this new implementation of the Access-based Lithologic Database. In addition we have integrated the PAPeRS database in the Access version so that search of both references and localities is now possible.

4. A Climate-Sensitive Sediment Database is now available for the Permian, Jurassic and present day which contains information on oil source rocks, phosphorites, reefs, coals, evaporites, aeolian sands and tillites (e.g. Figures 7, 8). This database is more focused and specialized than our Mesozoic-Cenozoic Lithofacies Database, but contains more varied and detailed information for each entry and is not limited to specific stage intervals within the period. Linked to these data are nine new maps for all of the Permian stages showing our reconstructed ocean water-mass patterns.

5. A large Floral Distribution Database, containing lists from 750 Permian, 450 Triassic and 950 Jurassic localities, has worldwide coverage and is being used to interpret precipitation and temperature patterns. Included are over 18,800 occurrence records of macro-floral genera and their correlation to geologic stage, literature reference and lithofacies data. A multivariate analysis has been performed for each of the time intervals, and is being used to relate the individual floras to specific climate biomes. This database is potentially of interest to basin analysis groups who need some basis for assigning initial surface temperatures in thermal modeling studies. Also, geochemists concerned with biomarker identification will find direct evidence in the floral lists from nearby areas for possible terrestrial components in the oil.

6. We have begun to compile data on paleotopography and the information is now complete, subject to editing, for some 55 uplifts in Gondwana (Figure 9). Included for each feature are data on current topography, geologic structure and geophysics, as well as the available geochronological information on the evolution of the system. Each event in the development of a mountain range is documented as to its timing, evidence, interpretation and the literature reference from which the information was derived.

7. Our Paleogeographic Atlas Project Reference System (PAPeRS) contains over 28,000 literature sources and these have been computer catalogued in terms of geographic area, geologic age, and subject matter. This is a sort of mini-Georef system that specializes in paleogeography and the full range of interests represented in our project. Our in-house library is particularly strong in articles on China and a number of oil companies have tapped this resource for photocopies of key papers on Chinese basins. The PAPeRS database has now been ported to the wintel-based Microsoft Access database manager and linked to the Lithologic database. This allows more ready access to the sources of stratigraphic information than was possible in the past.

Return to Top

PGAP Home Permian Jurassic Movies, Slideshows and Maps Publications Recent Abstracts (full text) PGAP Activities Links