Join us Friday, March 14, 2025
as Dr. Michael Simms
presents
Principles of Correlation of Sand Zones: Applications to Site Characterization
Abstract
The objective of geological correlation is to identify past timelines in a depositional formation. Successful chronostratigraphic correlations can help recognize continuity and connectedness of permeable (sand and silt) zones. Lithostratigraphic correlations of permeable intervals are the basis for identifying transport pathways for groundwater contamination, groundwater-supply aquifers, and storage zones for waste injection and CO2 sequestration.
In sand-clay sequences, correlations can be challenging. Sand zones that appear similar in cores or in geophysical logs at different boreholes can be deposited in similar depositional environments, but be unrelated. Experience in subsurface geology has shown that sand bodies should not form the basis for correlation in sand-clay sequences. Similar thicknesses and lithologic sequences or log signatures only indicate similar depositional environmental settings. Effective correlation methods include identification of marker horizons (biostratigraphic or chemostratigraphic), geomorphic interpretation of depositional facies, and sequence-stratigraphic surfaces such as flooding surfaces, abandonment surfaces and sequence boundaries. Geophysical data, including seismic reflection data, can confirm correlations depending on spatial scales and resolution.
The concept of hydrostratigraphic units can identify permeable zones and aquifers for mapping. Hydrostratigraphic unit identification includes plotting of groundwater levels to identify groups of sands with consistent hydraulic heads or to assess groundwater flow patterns (flow nets) in cross sections. Applications to Louisiana deposits of Holocene, Pleistocene, and Neogene ages will be discussed.
Biography
Dr. Michael Simms is a hydrogeologist with approximately 40 years of experience as an environmental geologist in subsurface geologic assessment, groundwater assessment, remediation, groundwater modeling, and groundwater resource evaluation. He works in the Industrial Environmental Division at GEC, Inc. of Baton Rouge. He has a B.A., M.A., and Ph.D. in Earth and Planetary Sciences from Johns Hopkins University, with specializations in hydrogeology, geochemistry, and sedimentology. He is a professional geologist and professional geoscientist, registered in Louisiana, Texas, Alabama, and Mississippi. He also is the Vice Chair of the Louisiana Board of Professional Geoscientists. Mike has been a member of the BRGS since 1985, and he has served as the Treasurer of BRGS since 2011. He also is a member of AAPG and serves in the House of Delegates on the Honors and Awards Committee.