Geology of Ore Deposits

, Volume 61, Issue 2, pp 185–197 | Cite as

Bladed Texture and Exploration Implications. A Case Study from the Kuklitsa Deposit, Krumovgrad Goldfield, SE Bulgaria

  • Irina MarinovaEmail author


This study demonstrates that the bladed texture, which is common in epithermal, low-sulfidation (adularia-sericite) precious metal deposits, can serves as exploration vector towards precious metal mineralization. The paper presents two styles of bladed texture in the Kuklitsa gold deposit (Krumovgrad goldfield, SE Bulgaria) observed at both different altitude and lateral position in respect to regional low-angle detachment fault. The first style has formed as a crackle breccia just above the detachment fault where bladed texture consists of 10–20 vol % pseudorhombic adularia, 90-80 vol % quartz, scarce pyrite, and electrum, which is often observed under optical microscope. The second style is present in steep veins which fill listric faults of sharp tectonic contacts. It is developed at a higher level relative to the detachment fault. Bladed texture there consists of 1–2 vol % pseudorhombic adularia, 99-98 vol % quartz, and scarce both electrum and pyrite. Electrum of the two styles of bladed texture comprises only gold and silver but in different proportions with a higher gold content for the first style: fineness of 765, on average, for the first style vs. fineness of 692 for the second one. In this way, it is found that the adularia abundance correlates positively with the electrum one and negatively with the quartz abundance. The author uses the proportions of adularia, quartz and electrum, the fineness of electrum, and the relative distance to the detachment fault to conclude that the first style of bladed texture has been formed at higher temperature relative to the second style. The author infers that the first style is promising for mineralization of higher grade. Methods used comprise field observations and sampling, optical and electron microscopy, powder X-ray diffraction and electron microprobe analysis.


bladed texture electrum adularia adularia-sericite deposits low-sulfidation boiling 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Bonev, N., Tokachka shear zone southwest of Krumovgrad in Eastern Rhodopes, Bulgaria: an extensional detachment, Annuaire l’Universite de Sofia, 1996, vol. 89, Livre 1 Geologie, pp. 97–106.Google Scholar
  2. Bonev, N., Structure and Evolution of the Kessebir Gneiss Dome, Eastern Rhodope, Ph.D. Thesis, Sofia: University of Sofia, 2002.Google Scholar
  3. Bonev, N., Burg, J.-P., and Ivanov, Z., Mezozoic Tertiary Structural Evolution of an Extensional Gneiss Dome the Kessebir-Kardamos Dome, Eastern Rhodope (Bulgaria-Greece), Int. J. Earth Sci., 2006, vol. 95, pp. 318–340.CrossRefGoogle Scholar
  4. Bonev, N., Marchev, P., Ovtcharova, M., Moritz, R., and Ulianov, A., U Pb LA-ICP/MS zircon geochronology of metamorphic basement and Oligocene volcanic rocks from the SE Rhodopes: inferences for the geological history of the Rhodope crystalline basement, Proceed. Annual Conference of the Bulgarian Geolog. Soc., Sofia, 2010a, pp. 115–116.Google Scholar
  5. Bonev, N., Spikings, R., Moritz, R., and Marchev, P., Timing of extensional exhumation of the Eastern Rhodope high-grade basement (Bulgaria): 40Ar/39Ar constraints, Proceed. Annual Conference of the Bulgarian Geolog. Soc., Sofia, 2010b, pp. 117–118.Google Scholar
  6. Bonev, N., Spikings, R., Moritz, R., Marchev, P., and Collings, D., 40Ar/39Ar age constraints on the timing of Tertiary crustal extension and its temporal relation to ore-forming and magmatic processes in the Eastern Rhodope Massif, Bulgaria, Lithos, 2013, pp. 264–278.Google Scholar
  7. Brown, K.L., Gold deposition from geothermal discharges in New Zealand, Econ. Geol., 1986, vol. 81, pp. 979–983.CrossRefGoogle Scholar
  8. Browne, P.R.L., Hydrothermal alteration in active geothermal fields, Annual Reviews Earth and Planet. Sci., 1978, vol. 6, pp. 229–250.CrossRefGoogle Scholar
  9. Chi, G. and Xue, C., An overview of hydrodynamic studies of mineralization, Geosci. Front., 2011, vol. 2, pp. 423–438.CrossRefGoogle Scholar
  10. Deming, D., Introduction to Hydrogeology, Boston: McGraw-Hill, 2002.Google Scholar
  11. Dong, G., Morrison, G., and Jaireth, S., Quartz textures in epithermal veins, Queensland, Classification, Origin, and Implication, Econ. Geol., 1995, vol. 90, pp. 1841–1856.CrossRefGoogle Scholar
  12. Dong, G. and Morrison, G., Adularia in epithermal veins, Queensland: morphology, structural state and origin, Mineral. Deposita, 1995, vol. 30, pp. 11–19.CrossRefGoogle Scholar
  13. Etoh, J., Izawa, E., and Wanatabe, K., Bladed quartz and its relationship to gold mineralization in the Hishikari low-sulfidation epithermal gold deposit, Japan, Econ. Geol., 2002, vol. 97, pp. 1841–1851.CrossRefGoogle Scholar
  14. Faure, K., Matsuhisa, Y., Metsugi, H., Mizota, C., and Hayashi, S., The Hishikari Au Ag Epithermal Deposit, Japan: Oxigen and Hydrogen Isotope Evidence in Determining the Source of Paleohydrothermal Fluids, Econ. Geol., 2002, vol. 97, pp. 481–498.CrossRefGoogle Scholar
  15. Georgiev, V., Metallogenic map of gold deposits in Bulgaria, in Gold Deposits of Bulgaria, Sofia: Zemya’93, 2007 (in Bulgarian with summary in English).Google Scholar
  16. Goranov, A., Kozhoukharov, D., Boyanov, I., and Kozhoukharova, E., Explanatory note to the geological map of Bulgaria at a 1: 100000 scale, Krumovgrad and Sape map sheets, Sofia: Avers, 1995 (in Bulgarian with English abstract).Google Scholar
  17. Goranov, A. and Atanasov, G., Litho-stratigraphy and formation conditions of Maastrichtian-Paleocene deposits in Krumovgrad District, Geol. Balcanica, 1992, vol. 22, pp. 71–82.Google Scholar
  18. Hedenquist, J.W. and Lowenstern, J., The role of magmas in the formation of hydrothermal ore deposits, Nature, 1994, vol. 370, pp. 519–527.CrossRefGoogle Scholar
  19. Hedenquist, J.W., Arribas, R.A., and Gonzalez-Urien, E., Exploration for epithermal gold deposits, Rev. Econ. Geol., 2000, pp. 245–277.Google Scholar
  20. Helgeson, H.C., Complexing and Hydrothermal Ore Deposition, Oxford: Pergamon Press, 1964.Google Scholar
  21. Henley, R.W., Truesdell, A.H., Barton, P.B., Jr., and Whitney, J.A., Fluid mineral equilibria in hydrothermal systems, Rev. Econ. Geol., 1984, vol. 1, pp. 115–127.Google Scholar
  22. Henley, R.W., The geothermal framework of epithermal deposits, Rev. Econ. Geol., 1985, vol. 2, pp. 1–24.Google Scholar
  23. Holland, H.D. and Malinin, S.D., The solubility and occurrence of non-ore minerals, Geochemistry of Hydrothermal Ore Deposits, 2nd Ed., New York: J. Willey & Sons, 1979, pp. 461–508.Google Scholar
  24. Izawa, E., Urashima, Y., Ibaraki, K., Suzuki, R., Yokoyama, T., Kawasaki, K., Koga, A., and Taguchi, S., The Hishikari gold deposit: high grade epithermal veins in Quaternary volcanics of southern Kyushu, Japan, J. Geochem. Explor., 1990, vol. 36, pp. 1–56.CrossRefGoogle Scholar
  25. Jelev, D., Khan Krum gold deposit, Ada Tepe prospect, in Gold deposits of Bulgaria, Sofia: Zemya’93, 2007, pp. 104–115Google Scholar
  26. Kunov, A., Stamatova, V., Atanasova, R., and Petrova, P., The Ada Tepe Au Ag-polymetalic occurrence of low-sulfidation (adularia sericite type) in the Krumovgrad district, Minno Delo i Geologia, 2001, vol. 4, pp. 16–20 (in Bulgarian).Google Scholar
  27. Marchev, P., Singer, B., Jelev, D., Hasson, S., Moritz, R., and Bonev, N., The Ada Tepe deposit: a sediment-hosted, detachment fault-controled, low-sulfidation gold deposit in the Eastern Rhodopes, SE Bulgaria, Schweizerische Mineralogische und Petrographische Mitteilungen, 2004, vol. 84, pp. 59–78.Google Scholar
  28. Marchev, P., Kibarov, P., Spikings, R., Ovtcharova, M., Marton, I., and Moritz, R., 40Ar/39Ar and U-Pb geochronology of the Iran Tepe volcanic complex, Eastern Rhodopes, Geologica Balcanica, 2010, vol. 39, pp. 3–12.Google Scholar
  29. Marinova, I., Preliminary data on the electrum mineralization in the Synap occurrence, Krumovgrad goldfield, Eastern Rhodope mountain, SE Bulgaria, in Mineral Diversity. Research and Preservation, Sofia: Earth and Man Foundation, 2012, pp. 161–170.Google Scholar
  30. Marinova, I., Particular distribution of electrum enrichments along sinusoidal-walled veinlets and geological implications: a case study from the Eocene low-sulfidation Khan Krum Deposit, SE Bulgaria, Horizons Earth Sci. Res., 2017, vol. 16, pp. 121–155.Google Scholar
  31. Marinova, I. and Nenova, P., Preliminary data on electrum mineralization in the Skalak occurrence, Krumovgrad Goldfield, Eastern Rhodope Mountain, SE Bulgaria, Proceed. Annual Conference of the Bulgarian Geolog. Soc., Sofia, 2007, pp. 46–47.Google Scholar
  32. Marinova, I. and Nenova, P., Preliminary data on electrum mineralization in Kaklitsa occurrence, Krumovgrad Goldfield, Eastern Rhodope Mountain, SE Bulgaria, Proceed. Annual Conference of the Bulgarian Geolog. Soc., Sofia, 2007, pp. 46–47.Google Scholar
  33. Marinova, I. and Tacheva, E., Boiling assemblages in the Kupel occurrence, Krumovgrad goldfield, SE Bulgaria. Proceed. the 1st International Electronic Conference on Mineral Science, July 16–31, 2018; MDPI AG, doi Scholar
  34. Marinova, I., Ganev, V., and Titorenkova, R., Colloidal origin of colloform-banded textures in the Paleogene low-sulfidation Khan Krum gold deposit, SE Bulgaria, Mineral. Deposita, 2014, vol. 49, pp. 49–74.CrossRefGoogle Scholar
  35. Marton, I., Formation, Preservation and Exhumation of Sedimentary Rock-Hosted Gold Deposits in the Eastern Rhodopes, Bulgaria. Ph.D. Thesis, Terre & Environment, 2009, vol. 84.Google Scholar
  36. Marton, I., Moritz, R., and Spikings, R., Application of low-temperature thermochronology to hydrothermal ore deposits: Formation, preservation and exhumation of epithermal gold systems from the Eastern Rhodopes, Bulgaria, Tectonophysics, 2010, vol. 483, pp. 240–254.CrossRefGoogle Scholar
  37. Marton, I., Jeleva, T., Dintchev, Y., Zhivkov, N., and Gosse, R., Sedimentary rock-hosted gold mineralization at Ada Tepe, Krumovgrad District, Bulgaria: review of prospect-scale geological, structural and geochemical features, Eocene to Miocene Hydrothermal Deposits of Northern Greece and Bulgaria: Relationships Between Tectonic-Magmatic Activity, Alteration, and Gold Mineralization, Littleton: Society of Economic Geologists, Guidebook Series, Field Trip (Balkans II), 2016, vol. 54, pp. 17–42.Google Scholar
  38. Moncada, D. and Bodnar, R.J., Gangue mineral textures and fluid inclusion characteristics of the Santa Margarita Vein in the Guanajuato Mining District, Mexico, Central Europ. J. Geosci, 2012, vol. 4, no. 2, pp. 300–309.Google Scholar
  39. Moncada, D., Baker, D., and Bodnar, R.J., Mineralogical, petrographic and fluid inclusion evidence for the link between boiling and epithermal Ag Au mineralization in the La Luz area, Guanajuato Mining District, Mexico, Ore Geol. Rev., 2017, vol. 89, pp. 143–170.CrossRefGoogle Scholar
  40. Nachev, I., Sedimentology and neomobilism, in Geodynamics of Balkans, Sofia: Tehnika, 1980.Google Scholar
  41. Nachev, I. and Nachev, C., Alpine Plate-Tectonics of Bulgaria, Sofia: Artik, 2001.Google Scholar
  42. Pal’yanova, G., Physicochemical modeling of the coupled behavior of gold and silver in hydrothermal processes: gold fineness, Au/Ag ratios and their possible implications, Chem. Geol., 2008, vol. 255, pp. 399–413.CrossRefGoogle Scholar
  43. Peycheva, I., Ovtcharova, M., Sarov, S., and Kostitsin, Y., Age and metamorphic evolution of metagranites from the Kessebir Reka region, Eastern Rhodopes Rb Sr isotope data. Abstracts of the XVI Congress of Carpatho-Balcan Geolog. Association, 1998, p. 471.Google Scholar
  44. Plotinskaya, O., Kovalenker, V., Seltmann, R., and Stanley, C., Te and Se mineralogy of the high-sulfidation Kochbulak and Kairagach epithermal gold telluride deposits (Kurama Ridge, Middle Tien Shan, Uzbekistan), Mineral. Petrol., 2006, vol. 87, pp. 187–207.CrossRefGoogle Scholar
  45. Shikazono, N. and Shimizu, M., Compositional Variations in Au Ag Series Mineral from Some Gold Deposits in the Korean Peninsula, Mining Geol., 1986, vol. 36, pp. 545–553.Google Scholar
  46. Shimizu, T., Matsueda, H., Ishiyama, D., and Matsubaya, O., Genesis of Epithermal Au Ag Mineralization of the Koryu Mine, Hokkaido, Japan, Econ. Geol., 1998, vol. 93, pp. 303–325.CrossRefGoogle Scholar
  47. Simmons, S.F. and Christenson, B.W., Origins of calcite in a boiling geothermal system, Am. J. Sci., 1994, vol. 294, pp. 361–400.CrossRefGoogle Scholar
  48. Simmons, S. and Browne, P., Hydrothermal minerals and precious metals in the Broadlands-Ohaaki geothermal system: implications for understanding low-sulfidation epithermal environments, Econ. Geol., 2000, vol. 95, pp. 971–999.CrossRefGoogle Scholar
  49. Simmons, S.F., Mauk, J.L., and Simpson, M.P., The mineral products of boiling in the Golden Cross epithermal deposit, New Zealand Minerals & Mining Conference Proceed., 2000, pp. 29–31.Google Scholar
  50. Skinner, B.J., Hydrothermal mineral deposits: what we do and don’t know, Geochemistry of Hydrothermal Ore Deposits, New York: J. Wiley & Sons, 1997, pp. 1–29.Google Scholar
  51. Kazalova-Stankova, T., Morphological types of gold mineralization in Kuklitsa prospect, Khan Krum deposit, Eastern Rhodopes, SE Bulgaria, Geologia i mineralni resursi, 2012, vol. 1–2, pp. 17–22 (in Bulgarian with English abstract).Google Scholar
  52. Staude, S., Bons, P.D., and Markl, G., Hydrothermal vein formation by extension-driven dewatering of the middle crust: an example from SW Germany, Earth and Planet. Sci. Lett., 2009, vol. 286, pp. 387–395.CrossRefGoogle Scholar
  53. Sultanov, A., Practical Guide to Sedimentology, Sofia: Tehnica, 1988.Google Scholar
  54. Tulloch, A.J., Mineralogical observations on carbonate scaling in geothermal wells as Kawerau and Broadlands, 4 th New Zealand Geothermal Proceed., 1982, pp. 131–134.Google Scholar
  55. Weatherley, D.K. and Henley, R.W., Flash vaporization during earthquakes evidenced by gold deposits, Nature Geosci., 2013, vol. 6, pp. 294–298.CrossRefGoogle Scholar
  56. White, N.C. and Hedenquist, J.W., Epithermal gold deposits: styles, characteristics and exploration, SEG Newsletter, 1995, vol. 23.Google Scholar
  57. Yardley, W. and Bodnar, R., Fluids in the Continental Crust, Geochemical Perspectives, 2014, vol. 3, pp. 1–127.CrossRefGoogle Scholar

Copyright information

© Pleiades Publishing, Ltd. 2019

Authors and Affiliations

  1. 1.Institute of Mineralogy and CrystallographyBulgarian Academy of SciencesSofiaBulgaria

Personalised recommendations