The fossil wood of East Cairo, Egypt: A mineralogical view

Open access


As part of the characterization of the petrified wood of East Cairo at the New Cairo Petrified Forest, representative samples collected from the area were studied by X-ray powder diffraction (XRD) and optical microscopy. The samples, as indicated by XRD analysis, are composed of quartz ± some goethite ± minor moganite ± minor gypsum ± trace calcite. The absence of moganite in some samples has been attributed to the transformation of moganite to quartz or to leaching processes. Under the optical microscope, some of the 10 petrified-wood samples are permineralized with mainly microcrystalline quartz (chalcedony), some with a combination of chalcedony and microgranular quartz, and some with microgranular quartz. The sequence of silicification is likely to have been either opaline precursor to chalcedony and quartz, or directly to chalcedony and quartz. The crystallinity indices (C.I.) of the quartz in the samples studied, measured using a standard X-ray powder diffraction procedure, are consistent with the petrographic findings. The chalcedonic samples have the least C.I. values, and the microgranular quartz samples the highest values.

If the inline PDF is not rendering correctly, you can download the PDF file here.

  • Buurman P. (1972). Mineralization of fossil wood. Scripta Geologia 12 1-43.

  • El-Faramawi M.W.A.K.I. (2008). Studies in the flora of the Cairo Petrified Forest. Ph.D. dissertation Botany Department Faculty of Sciences Ain Shams University Cairo Egypt.

  • El-Saadawi W. Kamal-El-Din M.M. Attia Y. & El-Faramawi M.W. (2011). The wood flora of the Cairo Petrified Forest with five Paleogene new legume records for Egypt. Review of Palaeobotany and Palynology 167 184-195.

  • Fournier R.O. (1985). The behavior of silica in hydrothermal solutions. In B.B. Berger & P.M. Bethke (Eds.).

  • Geology and geochemistry of epithermal systems. Reviews in Economic Geology 2 45-61.

  • Hassan K.M. (2010). Valences and site characteristics of iron in radioactive magmatic veins (Egypt): A Mössbauer and chemical study. Mineralogia 41(1-2) 23-33. DOI: 10.2478/v10002-010-0003-2.

  • Hassan K.M. (2015a). The iron mineralogy of Eocene fossil wood - A Mössbauer study from the Petrified Forest New Cairo Egypt. Accepted The Canadian Mineralogist.

  • Hassan K.M. (2015b). Stable isotopic signatures of the modern land snail Eremina desertorum from a low-latitude (hot) dry desert - A study from the Petrified Forest New Cairo Egypt. Chemie der Erde - Geochemistry 75(1) 65-72.

  • Hassan K. M. & Gunnlaugsson H. P. (2013). Characterization of barren granitic soils from the Nubian Desert (SW Egypt) by 57Fe Mössbauer spectroscopy. Mineralogia 44(1-2) 39-51. DOI: 10.2478/mipo-2013-0004.

  • Hatipoğlu M. & N Türk N. (2009). A combined polarizing microscope XRD SEM and specific gravity study of the petrified woods of volcanic origin from the Camlıdere- 82 Celtikci-Gudul fossil forest in Ankara Turkey. Journal of African Earth Sciences 53 141-157. DOI 10.1016/j.jafrearsci.2009.01.001.

  • Heaney P.J. & Post J.E. (1992). The widespread distribution of a novel silica polymorph in microcrystalline quartz varieties. Science 255 441-443. DOI: 10.1126/science.255.5043.441.

  • Iler R.K. (1979). The colloid chemistry of silica and silicates. New York: Wiley.

  • Jefferson T.H. & McDonald D.I. (1981). Fossil wood from South Georgia. British Antarctic Survey Bulletin 54 57-64.

  • Murata K.J. (1940). Volcanic ash as a source of silica for the silicification of wood. American Journal of Science 238 586-596.

  • Murata K.J. & Norman H. (1976). An index of crystallinity for quartz. American Journal of Science 276 1120-1130.

  • Mustoe G.E. (2008). Mineralogy and geochemistry of late Eocene silicified wood from Florissant Fossil Formation Beds National Monument Colorado. The Geological Society of America Geological Society of America Special Papers 2008 435 127-140. DOI: 10.1130/2008.2435(09).

  • Said R. (1962). The Geology of Egypt. New York: Elsevier Publishing Company.

  • Said R. (1990). The Geology of Egypt. Rotterdam Brookfield: A. A. Balkema Scurfield G. & Segnit E.R. (1984). Petrification of wood by silica minerals. Sedimentary Geology 39 149-167.

  • Stein C.I. (1982). Silica recrystallization of petrified wood. Journal of Sedimentary Petrology 52 1277-1281.

  • Sutherland J. (1994). Some aspects of petrification of Miocene wood from Kaipara Harbour New Zealand. Geoscience Reports of Shizuoka University 20 143-151.

Journal information
Impact Factor

CiteScore 2018: 0.48

SCImago Journal Rank (SJR) 2018: 0.185
Source Normalized Impact per Paper (SNIP) 2018: 0.14

All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 342 122 4
PDF Downloads 138 49 0