Reversed "Forward Modeling" from a Known Present, Database Development Into from Unknown Past

Allen Lowrie and Linda H. Jenkins
RFI Explorationists, Picayune, MS

The schema proposed is to develop a preliminary three-dimensional multilayered database from known present data. Extensive areas of the planetary surface exist where surficial characteristics have been remotely sensed with little or no penetrative data available. Examples of remote sensing include topography, magnetic, gravity, photographic and reflectance (at differing wavelengths) data that have been collected by satellite, airplane, and survey ships. The collection of penetrative borehole and seismic data is much less abundant by numerous orders of magnitude.

Interpretation begins with the delimiting of the various geologic/tectonic/physiographic provinces using a geologic history and then estimating rates of geologic evolution. The descent into the subsurface is by geologically determined sequences or by arbitrary units. With sediments interpreted using sequence stratigraphy, such units permit estimates of probable/possible sediment type and amount deposited in each assigned sequence.

In dealing with sediments and rocks from which a chronostratigraphic designation is not possible, then the subsurface descent may be conducted by units of arbitrary thickness. The thicknesses can be determined by understood geologic variations or any other criteria suitable to the interpreter.

In determining geologic/tectonic/physiographic provinces from remotely sensed data, the interpreter needs to be mindful of requirements for the mapping/databasing itself. By comprehending the databasing objectives, the interpreter can design the effort and parameters needed to derive the required objective. This technique has been successfully employed for local hazard determinations and regional refractive acoustic transmission for naval acoustics.

AAPG Search and Discover Article #90078©2008 AAPG Annual Convention, San Antonio, Texas