Northern Sacramento Valley Geologic Cross-Sections & Sand- Provenance Analysis Geology and Groundwater Conference Kelly Staton November 4, 2009

Study Area

Geologic Map of the Northern Sacramento Valley with Cross-section Locations A A’ B B’ C’ D’ D D C E E’E’

Geologic Cross-Sections

Project Time-Line & Background Begin drawing cross-sections based on DOGGR geophysical logs & previous literature Collect lithology samples & geophysical logs from 2009 DWR oversight of over 50 test-holes drilled in the northern Sacramento Valley Start cross-section revisions using bore hole data Perform sand provenance analysis; digitize and finalize geologic map Finalize cross-sections and write report Review and publish cross-sections, geologic map, and report

What We Used to Create the Cross- Sections Observation Well Drilling: Lithology Logs 3627 cutting samples from 38 test holes (approximately 36,270 feet of drilled hole sampled every ten feet) Geophysical Log Resistivity Signature 38 electrical resistivity logs Sand Sample Analysis 56 sand samples from 14 test holes and 5 surface exposure sites

What We Used to Create the Cross- Sections Division of Oil, Gas, & Geothermal Resources : Geophysical Log Resistivity Signature 126 electrical resistivity logs used on the cross-sections Reviewed over 500 e-logs Lithology Logs Reviewed over 500 lithology logs (not necessarily for the same gas wells as the e-logs)

What We Used to Create the Cross- Sections References/previous literature Major references for contacts Redwine, 1972 Helley and Harwood, 1985, 1987

Observation Monitoring Grid Prior to 2000 About 20 Sites (64 wells) Tehama Fm and Tuscan Fm Subsurface and Surface Exposures Tehama Formation Tuscan Formation

Observation Monitoring Grid 2000 to 2009 About 40 Sites (161 wells) Tehama Fm and Tuscan Fm Subsurface and Surface Exposures Tehama Formation Tuscan Formation

Observation Monitoring Grid Current About 60 Sites 225 wells Tehama Fm and Tuscan Fm Subsurface and Surface Exposures Tehama Formation Tuscan Formation

Cutting Samples

Observation Well Log Showing: Lithology Logs Well Construction Geophysical Log

10 X Vertical Exaggeration

Geologic Contacts

Sand Provenance Analysis Raymond Ingersoll, UCLA, and Martin Steinpress, Brown & Caldwell 56 sand samples from 14 test holes and 5 surface exposure sites 300 grain-count per sand sample Statistical analysis; % lithic grains Full report in Appendix B

Cross-Section and Sand Sample Location Map

Trilinear Diagram Lithic Volcanic, Metamorphic, and Sedimentary Percentages

Major Constituents

Sand Sample Analysis “Sand Pies” Ls - Lithic Sedimentary Lm - Lithic Metamorphic Lv - Lithic Volcanic

Sand Sample Analysis Photomicrographs

Tehama Formation Metamorphic & Sedimentary

Tuscan Formation Volcanics

Intermixing of Formations Lithic Metamorphic Lithic Sedimentary Lithic Volcanic

Geologic Report

Table of Contents

Figure 3 Geochronology of the Northern Sacramento Valley

Appendix A Northern Sacramento Valley Sand Provenance Study Ray Ingersoll, UCLA Martin Steinpress, Brown & Caldwell

Appendix B Observation Well Logs Showing Lithology Logs, Geophysical Logs, and Well Construction DWR, Northern Region Geologists and Engineers

Next Steps Base of Fresh Water Report Hydrogeology - Texture Analysis Water Quality Analysis and Report