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Columbia Natural Resources Allen 3-04 Core results and interpretations

Columbia Natural Resources Allen 3-04 Core results and interpretations. David C. Harris Kentucky Geological Survey. Line 1B Shear Wave. KY River Fault. Core Location. Depth. 23m. 40m. 58m. 76m. Line length: 240 meters. Stoner Branch Corehole.

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Columbia Natural Resources Allen 3-04 Core results and interpretations

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  1. Columbia Natural Resources Allen 3-04 Core results and interpretations David C. Harris Kentucky Geological Survey

  2. Line 1B Shear Wave KY River Fault Core Location Depth 23m 40m 58m 76m Line length: 240 meters

  3. Stoner Branch Corehole • Provide data on vertical distribution of dolomite • Evaluate dolomite in Black River • CNR drilled continuous HQ and NQ core from 27 to 1005 ft (306m); TD reached Oct. 23 • Penetrated several small faults in shallow section • Penetrated Ky. River Fault Zone in the Black River: 175 ft (53m) of fractured limestone and breccia • TD in Knox on footwall, 280 ft high to downthrown block

  4. Stoner Branch Well Location

  5. CNR 3-04 Allen

  6. <507FT> Subsea Depth SW NE GR CNPOR RHOB GAMMA_NEU 960 0 200 30 -10 2 3 0 200 30 Garrard Siltstone 40 ft faulted out in Garrard/Clays Ferry 860 100 Clays Ferry Formation 760 200 Trenton Ls 660 300 560 400 460 500 Black River Group Pencil Cave Bentonite 360 600 280 ft faulted out in Black River/Wells Creek 260 700 160 800 60 900 -40 1000 Wells Creek Dolomite -140 1100 St. Peter Sandstone -240 Knox Group 1200 -340 1300 ROME OIL & GAS CO COLUMBIA NATURAL RES LLC ALLEN JAMES B ALLEN JAMES B JR 3-04 1

  7. Calloway Creekdolomite49-53 ft

  8. Trenton Limestone335-339 ft

  9. Black River fault breccia847 ft

  10. Dolomite Distribution • Dolostone present from surface to about 220 ft. Gradation contact downward • Saddle dolomite limited to uppermost ~150 ft • Barite present in dolostone at 89 and 95 ft • Lexington (Trenton) has patchy dolomite in fine-grained lithologies • Minor dolomite in fault breccia matrix- no saddle dolomite

  11. Calloway Creek Dolostone Allen 3-04 98 ft

  12. Calloway Creek Dolostone Allen 3-04 51 ft

  13. Allen 3-04 51 ft Calloway Creek dolostone

  14. Allen 3-04 89 ft Barite in Calloway Creek dolostone

  15. Allen 3-04 89 ft. Barite in dolostone

  16. Calcareous dolostone Clays Ferry Allen 3-04 208 ft Calloway Creek Allen 3-04 118 ft

  17. Lexington Ls. (Trenton) Fine-grained dolomite replacement of micrite Allen 3-04 237 ft Allen 3-04 343 ft

  18. Allen 3-04 483 ft Allen 3-04 323 ft Lexington Limestone

  19. Fault Breccias • Calcite, dolomite, sphalerite, barite, pyrite mineralization present • Abundant evidence of multiple fault reactivation • Clasts of Knox and St. Peter Ss transported over 200 ft up fault • Evidence for significant upward fluid flow

  20. 805-814 731-741 675-685

  21. Camp Nelson Ls. Allen 3-04 698 ft Sphalerite along stylolite

  22. Black Riverbreccia withsphalerite698 ft

  23. Camp Nelson Ls. Allen 3-04 718 ft Sphalerite in fracture

  24. Black Riverfault breccia with multiple calcite generations823 ft

  25. St. Peter Sandstone Allen 3-04 915 ft

  26. Allen 3-04 915 ft St. Peter Ss

  27. Allen 3-04 915 ft St. Peter Ss breccia clast

  28. Allen 3-04 679 ft Knox clasts and St. Peter sand

  29. Allen 3-04 673 ft St. Peter Ss breccia clast

  30. Allen 3-04 742 ft St. Peter Ss breccia clast

  31. Key Interpretations • Pervasive dolomitization confined to upper part of section • Alteration of ferroan saddle dolomite not observed, may be limited to surface • Poor porosity development in dolostone- cemented by dolomite: due to proximity to fault? • Barite, sphalerite, pyrite mineralization confirmed in fault zone and in dolostone • St. Peter Sandstone was cemented early, brecciated by faulting, with clasts and sand grains transported upward over 200 ft by fluid flow. Not a likely conduit for fluid flow.

  32. Problem • Dolomitization decreases downward, toward fault despite evidence for hydrothermal fluid movement

  33. Burial History • CAI of <1.5 (Harris et al. 1978) • <90 degrees C • 600-800 meters maximum burial estimated by Andrews (2004) on Cincinnati Arch

  34. Regional Distribution of Dolostone Bodies, Central Kentucky

  35. Models for Dolomite Distribution at Stoner Branch • Important locality since similar vertical segregation of dolomite may occur in producing trends • Trend suggests a geochemical mechanism may be more important than stratigraphic control

  36. Working Hypotheses • Downward fluid movement (reflux) • Pro: dolomite decreases downward • Con: inconsistent with isotope data; lightbulb was definitely altered from bottom-up • Shale dewatering: • Pro: Dolomite confined to shaly Clays Ferry/Calloway Creek interval • Con: why not dolomtized everywhere; problems with model, volume of Mg

  37. Working Hypotheses • Diagenetic difference (Trenton cemented) • Pro: younger rocks dolomitized • Con: evidence than mineralizing brines moved through Trenton, but with limited dolomitization • Conduit control: main fault tight, minor faults active conduits • Pro: difference in cementation/mineralization of major and minor faults • Con: geometry of dolostone body on major fault

  38. Working Hyptheses • Temperature gradient, upward cooling: • Not feasible due to retrograde solubility of carbonate minerals • Fluid degassing / boiling: pressure decrease causes CO2 to come out of solution, decreasing carbonate solubility • Pro: explains upward increase in dolomitization, documented in mineral deposits • Paleo-structure of dolomitized zones may correlate • Con: no data to support yet- fluid inclusions can help

  39. Regional Distribution of Dolostone Bodies, Central Kentucky

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