Portland State University PDXScholar Dissertations and Theses Dissertations and Theses 1990 Subsurface and geochemical stratigraphy of northwestern Oregon Olga Berenice Lira Portland State University Follow this and additional works at: https://pdxscholar.library.pdx.edu/open_access_etds Part of the Geology Commons, and the Stratigraphy Commons Let us know how access to this document benefits ou.y Recommended Citation Lira, Olga Berenice, "Subsurface and geochemical stratigraphy of northwestern Oregon" (1990). Dissertations and Theses. Paper 4314. https://doi.org/10.15760/etd.6198 This Thesis is brought to you for free and open access. It has been accepted for inclusion in Dissertations and Theses by an authorized administrator of PDXScholar. Please contact us if we can make this document more accessible: [email protected]. AN ABSTRACT OF THE THESIS OF Olga Berenice Lira for the Master of Science in Geology presented May 3, 1990. Title: Subsurface and Geochemical Stratigraphy of Northwestern Oregon. APPROVED BY MEMBERS OF THE THESIS COMMITTEE: Richard E:hOms Lithological, geophysical, paleontological and geochemical methods were used in order to define the contact relationship between the Keasey and the Cowlitz formations in northwestern Oregon. Drill cuttings from six wells located in Columbia County were analyzed by the Instrumental Neutron Activation Analysis (INAA) method. The 2 concentrations of K, Th, Rb and Sc/Co ratio in the samples established four different groups: 1) High K, Rb, and TH, with low Sc/Co ratio typical of Cowlitz sediments. 2) Low K, Th and Rb and high Sc/Co ratio, more characteristics of the Keasey Formation. 3) Very low concentrations of Rb and high Sc, which is indicative of basaltic volcanism. 4) vertically varying K, Th and Rb concentrations. The provenance of group four is uncertain, but it may represent reworked sediments or the interf ingering of the Keasey and the Cowlitz formations. Plots of these elements vs. depth define the geochemical contacts between the formations. The contact was also determined by interpretations of geophysical logs, the gamma ray log being the most useful. This log responds to chemical differences between the Cowlitz Formation and the Keasey Formations or local volcanic sediments. The apparent interfingering of these two formations is observed in wells drilled off the Nehalem arch of Armentrout and Suek (1985). In the upper part of the arch the Cowlitz Formation has been eroded. Therefore, the contact between the Cowlitz and the Keasey formations can be defined as conformable where they apparently interfinger and unconformable where erosion or nondeposition is evident. The contact between the Keasey and Cowlitz formations, as interpreted from the geochemical data and gamma ray logs, is the same and seem to reflect a lithologic break. 3 However, the paleontological time boundary between the Refugian and Narizian stages does not coincide with the formational boundary in all the wells, but occurs within the Keasey Formation. Therefore, Keasey Formation was deposited during both Narizian and Refugian time. In localities where the geochemical, paleontological, and lithological contacts coincide an unconformity is defined. SUBSURFACE AND GEOCHEMICAL STRATIGRAPHY OF NORTHWESTERN OREGON by OLGA BERENICE LIRA A thesis submitted in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE in GEOLOGY Portland State University 1990 TO THE OFFICE OF GRADUATE STUDIES: The members of the Committee approve the thesis of Olga Berenice Lira presented May 3, 1990 • ./James G. Ashbaiigh / l c. William Savery, Interim Vic Provost for Graduate Studies and Research. / ACKNOWLEDGMENTS I want to acknowledge and thank the faculty of the Geology Department, Portland State University, and especially to Dr. Marvin Beeson for his encouragement, advice, dedication, friendship, and critical review of this research topic. Thanks to Dr. Gilbert Benson who initiated the study. I would like to express my gratitude to Jack Meyer from Oregon Natural Gas Development Corporation for his invaluable help and advice. Ors. Ansel Johnson, Richard Thoms, and Robert Van Atta my thanks for their collaboration and review of the thesis. Also I would like to extend my appreciation to Dennis Olmstead and Dan Wermiel from the State of Oregon Department of Geology and Mineral Industries for their assistance; Technical assistance by Michael Pollock and Gene Pierson is also appreciated and thanks to Dr. John Allan and Tom Taylor for addicting the thesis and to Keith Brunstand for his computer assistance. I dedicate this work to my parents, Jesus Dario Lira and Carmen Reyes and thank them for the years of love and understanding, financial aid and moral guidance thoughout my life. TABLE OF CONTENTS PAGE ACKNOWLEDGEMENTS • . • • . • . • • . • • • • • . • . • • iii LIST OF TABLES................................ vi LIST OF FIGURES.. • . • . • . • • • • • • . • • • • . • . • • • vii LIST OF PI.ATES. • . • . • . • . • . ix INTRODUCTION. • . • • • . • . • • . • . • . • . • • . 1 Purpose . 2 Previous Work . 5 General stratigraphy of the study Area.... 7 Hydrocarbon Potential..................... 8 REGIONAL LITHOSTRATIGRAPHY.................... 11 Tillamook Volcanics....................... 11 Hamlet Formation (also called Yamhill Form.ation) . 13 Cowlitz Formation......................... 17 Keasey Formation. • . 2 2 The Jewell Member of the Keasey Formation. 24 Pittsburg Bluff Formation................. 25 Scappoose Formation....................... 27 Columbia River Basalt Group •.•.•..•..•..... 28 Smuggler Cove Formation ..•.•.•••••.••••...• 28 Sager Creek Formation •.•.••..•..•.•.•.•..•. 30 v Astoria Formation .•..••••. 31 Troutdale Formation ••. 32 BIOSTRATIGRAPHY .••....•••.•••••. 34 ANALYTICAL PROCEDURES ••• 37 Geochemistry. 3 7 Geochemistry Data and Discussion ••••••••••• 41 SUBSURFACE ANALYSIS ••••.•••••••••. • • • • • * • • • • • • • 66 Subsurface Correlation •••••••.. 66 Cross Section Interpretation •• 72 DISCUSSION AND CONCLUSION. 76 Conclusion .................... 78 Problems and Suggestions •••••.•••..•.••.••. 79 REFERENCES. 80 APPENDIX ... 85 LIST OF TABLES TABLE PAGE I Geochemistry, Oregon Natural Gas IW 22d-10..... 43 II Geochemistry, American Quasar Petroleum Corp. Longview Fiber #25-33 •.. 46 III Geochemistry, American Quasar Petroleum Corp, Crown Zellerbach #30-33. 48 IV Geochemistry, Exxon Company- USA. G.P.E. Federal Com.# 1 .•••.........•..•. 51 V Geochemistry, Reichhold Energy Corp. Crown Zellerbach #2.. • • • • . • . 56 VI Geochemistry, Arco Oil and Gas Company Columbia County #31-8 ..•••.•••....•..•.. 58 VII Geochemistry, Oregon Natural Gas. IW 220-10. Core samples .••.••.••.....•.• 62 VIII Geochemistry, Sc/Co ratio ••.•.••....••..•.. 63 LIST OF FIGURES FIGURE PAGE 1. Map showing well locations in the study area . ....................... 4 2. Regional stratigraphic correlation •.•..•.•. 12 3. Biostratigraphy of fourteen wells drilled in northwestern Oregon showing the contact between the Refugian and Narizian Stages........................ 36 4. Regional Bouguer gravity map for northwest Oregon and southwest Washington showing the location of the Mist gas field on the east flank of the northern Coast Range gravity high...... 39 5. Variation of elements concentrations with depth. IW 220-10 ••.•..•..•.•..... 45 6. Variation of elements concentrations with depth. Longview Fiber #25-33...... 47 7. Variation of elements concentrations with depth. Crown Zellerbach #30-33.... 49 8. Variation of elements concentrations with depth. GPE. Federal Com. #1....... 53 viii 9. Sc vs Th. Comparison of GPE. Federal Com. #1 basalts with basalts from other sources . ............................... 54 10. Variation of elements concentrations with depth. Crown Zellerbach #2 . ...•... 57 11. Variation of elements concentrations with depth. Columbia County #31-B •••••. 60 12. Influence of local basaltic volcanics based on Sc concentration.............. 62 \ LIST OF PLATES PLATE I Subsurface stratigraphy of northwestern Oregon. Cross section 1. II Subsurface stratigraphy of northwestern Oregon. Cross section 2. INTRODUCTION Northwestern Oregon has been the focus of intensive gas and petroleum investigation since the discovery of economic quantities of natural gas in the Clark and Wilson sandstone unit of the upper Eocene Cowlitz Formation by Reichhold Energy near Mist Oregon in 1979 (Newton, 1979; Armentrout and Suek, 1985). The Cowlitz Formation consists of two units: the first is a basal fine grained arkosic sandstone containing small flakes of mica, which is named the Clark and Wilson sand and which is the gas reservoir in the Mist Field (Columbia County) ; the second is an overlying unnamed sequence of siltstone and sandstones (Newton,1979; Bruer and others,1984; Armentrout and Suek 1985; Niem and others 1985). The Cowlitz Formation is overlain by the Keasey Formation which consists of tuffaceous mudstone and siltstone with minor volcaniclastic sandstone. The contact relationship between the Cowlitz Formation and the Keasey Formation has been described as unconformable in both surface and subsurface sections based on lithology, the abrupt change from Narizian to Refugian microfauna, and geophysical logs (Newton, 1979; Van Atta, 1971; Armentrout and Suek, 1985; Niem and others, 1985). However, Harry John Meyer from Oregon Natural Gas (personal communication, 1989) 2 observed an interbedding relationship in one core and in the gamma log from a well in the Mist field. Leonard Farr (1989) describes the contact