IAEA TM On Origin of SUD: A global perspective  Origin of gray-green sandstone and newexploration model for Dongsheng sand...
IAEA TM On Origin of SUD: A global perspectiveOutline1 Geological setting2 Unique features of the deposit3 Origin of grey-...
1 Geological SettingLocation:NE of Ordos Basin inNorth ChinaSize: 3x105 km2Signature:Compound basinsince palaeozoic
1 Geological Setting Pre-JurassicBasements:Archean andProterozoic highlymetamorphic rocksand migmaticgranites Paleozoic...
1 Geological Setting Energyresource Basin:Oil & Gas
Coal andCoal gasC-P Coal(Pink)T3 Coal (light Yellow)J1-J2 Coal (Yellow)
1 Geological Setting                 Mesozoic covers & ore bedsSeries     Group/     Sym. (m) Lith.                       ...
1 Geological Setting  Ore Bed: Zhiluo Formation(J2)Ore bed
1 Geological SettingOre hosting sedimentary formation   Sedimentary facies: Braided stream   Lithology: Coarse-grained ...
Ore sedimentation sequences and lithology           Outcrop                              Borehole core                    ...
Braided stream system                        Uranium in                        Braided                        distributary...
1 Geological SettingTectonics                 (J) The Dongsheng tectonic  slope block:  dipping southwards or  SW with 2...
1 Geological Setting   TectonicsThe Zhungeerzhao-Wangjiata Fault:Contributions formineralization:A suitable hydrodynam...
2 Unique features of the deposit(1) Uranium mineralization controlled by the redox   zone between grey and grey-green sand...
2 Unique features of the deposit(2) Coffinite dominant, not pitchblende                       Coffinite crystal
2 Unique features of the deposit (3) Complex ore body shapes                         Shape of ore bodyCross section of ore...
3 Origin of grey-green sandstoneGreenish sandstone originated from oil-gassecondary reduction processes:Secondary reducti...
3 Origin of grey-green sandstoneMineralogical evidence                         Oxidization residual              Limonite...
3 Origin of grey-green sandstoneGeochemistry                              Fe2O3/  Elements   CaO CO2    S               U...
3 Origin of grey-green sandstoneGeochemistry     Contents of hydrocarbon( L/kg) No. Lithology          Methane Ethane Pr...
3 Origin of grey-green sandstoneAbundant oil and gas in greenish sandstones         Oil-Gas Inclusions
4 Metallogenic and exploration model   It can be concluded that the uraniummineralization mechanism of the sandstone typeu...
4 Metallogenic and exploration modelSuperposition metallogenic & exploration model(A) Preliminary enrichment stage       ...
4 Metallogenic and exploration modelSuperposition metallogenic & exploration model (B) Paleo-phreatic oxidation stage    ...
4 Metallogenic and exploration model(1)Phreatic oxidation  process(J3)  Geochemically  Vertical Zonations:  U、V、Mo、Se、  Re
4 Metallogenic and exploration model(C) Paleo-phreatic+ Paleo-interlayeroxidation stages             125~65Ma
4 Metallogenic and exploration model                        U(2) Interlayer  oxidation  process (K1-E1)GeochemicallyHorizo...
4 Metallogenic and exploration model(2)Interlayer      S   oxidation   process  Horizontal  Zonations:     Shape of  U 、 V...
4 Metallogenic and exploration modelUranium found in the redox zone: formedby both paleo-phreatic and interlayeroxidation ...
Superposition metallogenic & exploration model(D) Oil-gas +Thermal modification stages                                   ...
4 Metallogenic and exploration modelHydrothermal events:  Temperatures: 70oC to 170oC, Salinity from 8%  to 20%   148℃、8....
4 Metallogenic and exploration model             Hydrothermal process:             Hydrothermal mineral association:Pyrit...
4 Metallogenic and exploration modelSuperposition Metallogenic ModelSuperposition of metallogenic processes  Phreatic+i...
4 Metallogenic and exploration modelNew exploration indicationThe Dongsheng deposit has unique features andunderwent comp...
谢 谢Thank you
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03 li ziying iaea2012.5.29

  1. 1. IAEA TM On Origin of SUD: A global perspective Origin of gray-green sandstone and newexploration model for Dongsheng sandstone uranium deposit in oil-gas and coal productive Ordos basin, China Dr. Ziying LI Beijing Research Institute of Uranium Geology 2012.5.29-6.1 2007.11.1-10, Trivandrum
  2. 2. IAEA TM On Origin of SUD: A global perspectiveOutline1 Geological setting2 Unique features of the deposit3 Origin of grey-green sandstone4 Metallogenic and exploration model
  3. 3. 1 Geological SettingLocation:NE of Ordos Basin inNorth ChinaSize: 3x105 km2Signature:Compound basinsince palaeozoic
  4. 4. 1 Geological Setting Pre-JurassicBasements:Archean andProterozoic highlymetamorphic rocksand migmaticgranites Paleozoic lightlymetamorphic rocks
  5. 5. 1 Geological Setting Energyresource Basin:Oil & Gas
  6. 6. Coal andCoal gasC-P Coal(Pink)T3 Coal (light Yellow)J1-J2 Coal (Yellow)
  7. 7. 1 Geological Setting Mesozoic covers & ore bedsSeries Group/ Sym. (m) Lith. Dep. Fm.Quat. Q >41 Quaternary sands and soilsLower Zhidan K1 1780 Red and gray sandstone andCretaceous Group mudstone;Alluvial, fluvial and eolian origins.Upper Fenfanghe J3f 971 conglomerate Poorly developed, Brown-redJurassic Fm. Anding J2a 300 Fine-grained red or brownish red siltstone Fm. and mudstoneMiddle Zhiluo Fm. J2z 300 Gray, greenish sandstone, siltstone and UJurassic mudstone Yanan Fm. J2y 450 Arkosic sandstones, siltstone and mudstone C, U interbedsLower Fuxian J1f 127 Siltstone and arkosic sandstoneJurassic Fm.Upper Yanchang T3y >3000 Gravel-bearing sandstone with siltstone and Oil, CTriassic Fm. mudstone interbeds
  8. 8. 1 Geological Setting Ore Bed: Zhiluo Formation(J2)Ore bed
  9. 9. 1 Geological SettingOre hosting sedimentary formation Sedimentary facies: Braided stream Lithology: Coarse-grained arkosic sandstones Thickness: 20 to 40 meters Uranium contents: 3 to 5 ppm Cementation: Loosely cemented. Ratio of sandstone to mudstone: 2:1 Extension: stable, connected to each other Reducing materials: 0.5 to 1.5%.
  10. 10. Ore sedimentation sequences and lithology Outcrop Borehole core Borehole core
  11. 11. Braided stream system Uranium in Braided distributary Channels
  12. 12. 1 Geological SettingTectonics (J) The Dongsheng tectonic slope block: dipping southwards or SW with 2o-5o. Recharge-runoff- discharge hydrodynamic (K) system Dongsheng block provided the basic conditions for uranium mineralization.
  13. 13. 1 Geological Setting  TectonicsThe Zhungeerzhao-Wangjiata Fault:Contributions formineralization:A suitable hydrodynamicdischarge regimeGenerate a reducingenvironment
  14. 14. 2 Unique features of the deposit(1) Uranium mineralization controlled by the redox zone between grey and grey-green sandstones Greenish Sandstone Paleo-phreatic oxid. Interlayer oxid. Ore body Gray Sandstone
  15. 15. 2 Unique features of the deposit(2) Coffinite dominant, not pitchblende Coffinite crystal
  16. 16. 2 Unique features of the deposit (3) Complex ore body shapes Shape of ore bodyCross section of orebody shape
  17. 17. 3 Origin of grey-green sandstoneGreenish sandstone originated from oil-gassecondary reduction processes:Secondary reduction processes: Took placeafter the formation of uranium depositGreen or gray-green sandstones: Paleo-oxidation zone chloritization andepidotization.
  18. 18. 3 Origin of grey-green sandstoneMineralogical evidence Oxidization residual Limonite Pyrite
  19. 19. 3 Origin of grey-green sandstoneGeochemistry Fe2O3/ Elements CaO CO2 S U FeO Greenish S. 3.96 2.83 0.04 0.41 3.4 Grey S. 1.64 1.02 0.75 0.12 14.3
  20. 20. 3 Origin of grey-green sandstoneGeochemistry Contents of hydrocarbon( L/kg) No. Lithology Methane Ethane Propane Gray-green fine- 3 445 61 19 grained sandstone Gray fine-grained 4 255 33 14 sandstone Green medium-fine 3 620 81 23 grained sandstone Gray medium-fine 3 257 36 13 grained sandstone
  21. 21. 3 Origin of grey-green sandstoneAbundant oil and gas in greenish sandstones Oil-Gas Inclusions
  22. 22. 4 Metallogenic and exploration model It can be concluded that the uraniummineralization mechanism of the sandstone typeuranium deposit in the northeastern Ordos Basinis very complicated, which underwent multiplemetallogenic processes, and superpositionmetallogenic & exploration model established: Preliminary enrichment process Paleo-phreatic oxidation process Paleo-interlayer oxidation process Oil-gas secondary reforming process Thermal modification process
  23. 23. 4 Metallogenic and exploration modelSuperposition metallogenic & exploration model(A) Preliminary enrichment stage 170Ma
  24. 24. 4 Metallogenic and exploration modelSuperposition metallogenic & exploration model (B) Paleo-phreatic oxidation stage 160~135Ma
  25. 25. 4 Metallogenic and exploration model(1)Phreatic oxidation process(J3) Geochemically Vertical Zonations: U、V、Mo、Se、 Re
  26. 26. 4 Metallogenic and exploration model(C) Paleo-phreatic+ Paleo-interlayeroxidation stages 125~65Ma
  27. 27. 4 Metallogenic and exploration model U(2) Interlayer oxidation process (K1-E1)GeochemicallyHorizontal Zonations: MoU、V、Mo、Re 、S…
  28. 28. 4 Metallogenic and exploration model(2)Interlayer S oxidation process Horizontal Zonations: Shape of U 、 V 、 Mo 、 ore body Re、S …
  29. 29. 4 Metallogenic and exploration modelUranium found in the redox zone: formedby both paleo-phreatic and interlayeroxidation processes. ilmenite
  30. 30. Superposition metallogenic & exploration model(D) Oil-gas +Thermal modification stages 20~8Ma
  31. 31. 4 Metallogenic and exploration modelHydrothermal events: Temperatures: 70oC to 170oC, Salinity from 8% to 20% 148℃、8.68Wt%NaCl 170℃、 3.39Wt%NaCl
  32. 32. 4 Metallogenic and exploration model Hydrothermal process: Hydrothermal mineral association:PyriteLimonite GalenaSphalerite
  33. 33. 4 Metallogenic and exploration modelSuperposition Metallogenic ModelSuperposition of metallogenic processes Phreatic+interlayer Oxidation Oil-gasreworking Hydrothermal reworkingSuperposition of different U sources Ore beds Provenence area Oil &GasSuperposition of metallogenic fluids U-bearing Water Oil-Gas Thermal Fluid
  34. 34. 4 Metallogenic and exploration modelNew exploration indicationThe Dongsheng deposit has unique features andunderwent complicated metallogenic processes,among them oil-gas reforming process playedvery important roles in uranium mineralization.So correct identification on greenish sandstonesformed under paleo-oxidization and reformedby oil-gas secondary reduction is very importantto explore for uranium deposits, especially inthose basin producing oil-gas…
  35. 35. 谢 谢Thank you

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