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10 B* * %& %&, "" ;,K ' *,G 6) U & 8* A 6 A >K B <A*.[ ] '%% U &*, 8* 42 8 A@H #* T" 8 A'"4,,, ƒ= ;62*, 8 }% " " 4 * \"" K9 "3 * (; 6 "3 '% *.[ 6(* ] ',& % "" : * * Y 2 Q <" F ^ % )6 * * ;A 6" 8 A "3 * >(& 8 A, U &* 2 8,, X[K * t '& >2 * AH U*,F * ^,F_ F BH 6) X,K \"" t T9 *, _ [ '% H * ~ * [ k] 'A Y *' G ^ "2 B # %" '9 :;. < ("6 O b* &, G` #* \3.[ ] * 9>;6K b* &, ^ 46 ƒ[ 6(* 8 A T " "" "" >;. #* \3 ; G R ' )4)9H 8 A )"& (% * >" /6 * % '# 8 A>"& 2*,G / * ') j *T, B 8 * H * TO 9 ; 'P 8 A' # (".[ ],& " 9 "" 8 A (*,G, "& : * > ), 8* * 42 8 A@H #* %") G >;. 8* # ", \"" :6) 9 % B T" J% #* \"" U &*.',& 8 A@, #* DE* "3 >"()9 8* AH 8 AB, = X,Q ) 6&* * P ' # * # "3 8 A>"&,G 6 * '% H * 6(* 8 A 6) 8 9 ; 'P <" ^ % X[K * X 2 A B " # X, b* & "" 8* 9>;6K X' K X[K *, 8 "2 \"" ^ % X[K * X' * %. * ^ % 'K.'A Y B T;A,Q \"" T #* K& 'A 8 A 42 # G* Z# 8 A )E,3,"* 8 A 6& '% 6(* 8 A ") G \"" A+,%"* (Stereom pores) + 6* 6 [K * 8 A )E Y 6 "" K 8* 42 B " "" 8*.,& 42 '& U &* '& 6) 8 Š3X[K * A 6,3 "2* b * & ^ % [K * # *.',& " L9 (j, : * * ++ 6). * %" '9 T O '& >2 >,Q \"" 8 A# " '& >2 Z# 8 A )E,3, 4 B # * AH 8 A " * 8 A,4, AH 8 AB, B, c 6 9 % B ;" ao3 + H4SiO4 + H = SiO2 + a + HO3 + 2H2O, or ao3 + H4SiO4 + O2 = SiO2 + a++ + 2HO3 + 2H2O, [ ] X[K * \"",G, "" \ \"" 6) 9 ; 'P 8 A' #.'& (' # * # 6).[ ] " ^,_ (porefilling) 42 8 '%% 3 2*, )4)9H,6)"& ' # #* * ƒ= ;62* ABH. * * (;.',& ^,_ 8 * H 8 AT9 *, X[K *, 8 A,; " 9 < \"" /6 "" 8 A>" 2*, + V :,& E "" 8 A %4* X,(" * #* ' *,9 '& >2 <" ^ % &, "" 8 6,3 *.'%& * Y 8 A )"& ^,_ '), 8 A,; 6 "3 b * & (; L9 +' 9 S #* ') 6 %& 6 "" #.'%& U &* "E ;"& K ^* "" 9 'A <" ^ % X[K * *T * ^,_ ^ 46 "" " * ^ % ' '& X[K * Q = < T"% * " " ^,_.'& \"" * (; 6(* 6", * H D" 9 8 A H *,.'&,

11 ... "3 \"" 8 A >"()9 8 '%% X 6% > *,. k ;& 'G "B* * r"i #,s 3 %& %"~" kœ.+ %"I 8,. [ ] ^, %& " # B # B* * %& " 6m '9 Q. ( kœ ),)m * 'a ^ )6m* [3] Rutner A., Nabavi M. H., Alavi M., "Geology of the OzbakKuh Mountains (Tabas area, East Iran)", Geological Survey of Iran, (96) 33. [4] Stocklin J., Eftekharnezhad J., HushamandZadeh A., 99, "Geology of the Shotori Range (Tabas area, East Iran)", Geological Survey of Iran Report No. 3 (99) 69. [] Maliva R., Siever R., "Mechanisms and controls of silicification of fossils in limestones", Journal of Geology 96 (988) [6] Maliva R.G., "Silicification in the Belt Supergroup (Mesoproterozoic), Glacier National Park, Montana, USA", Sedimentology 48 (2) [7] Pope M., "herty carbonate facies of the Montoya Group, southern New Mexico and western Texas and its regional correlatives a record of Late Ordovician paleoceanography on Palaeogeography, southern Laurentia", Palaeoclimatology, Palaeoecology 2 (24) [8] Tobin K. J., "A survey of Paleozoic microbial fossils in chert", Sedimentary Geology 68 (24) 7 7. [9] Schmitt J. G., Boyd D.., "Pattern of silicification in Permian pelecypods and brachiopods from yoming", Journal of Sedimentary Petrology (98) [] Bullen S. B., Sibley D. F., "Dolomite selectivity and mimic replacement", Geology 2 (984) 668. [] Popp B. N., Anderson J. F., Sandberg P. A., "Textural, elemental and isotopic variation among constituents in Middle Devonian limestones, North America", Journal of Sedimentary Petrology 4 (986), [2] Bathurst R. G.., "arbonate sediments and their diagenesis", Second enlarged edition, Elsevier Scientific Publishing ompany, New York, (97) 68. [3] Hein J. R., Karl S. M., "omparison between Open Ocean and continental margin chert * P "N 9 6 " DE* c *.' * '& %& T" A 4* 6 %") G >;. *,Q A'"I,% < T"% B, '% #* ' H " \%G 6(* 8 A 8*,G A'"I,% (;. ; "" T 7 B*'.'%A X2 A 6(* 8 A %& %") G T9 *, U, 8* 6(* 8 A,; * P "6* * %") G T9 *, 8 '%% X 6% ' *,9 ; T " Kp* V 9 * 6 "3 b * &. * \3 DE*, ^ 46 "2* 2 %" '9 b * & %") G " & V 9 * * BH / " ; ƒ[ d 6&* 6)" 8 A> 9T " * %& " 2 T" B* *' G * 6(* K} 8 "2 U, "" '% * A,3,"* D" 9 %* 8* 8 6)" %9 'A*,& A,3,"* >"P #* * < T"% Q A,3,"* 8* 6& U, A8* B* *' G 6(* T.'& ^*,G, * * 62 ], 2 * (; * * Y 8 '%% X 6%,6 '% * * A'"I,% A,3,"* >"P 3,( (" fq ; #* %") G '% * *. * A ", 9 AB G.' * 6&*,Q "" 8 ' '3 ABH 9< #* 6(* 8 A T 8 A'% * K9 * ")"3 4",,6)"& ' # 4 ("6 O,G '& %") G T9 *, "" b * &, "" 8 ' '3 #*.' * '& >"()9 <( *,K. 2 8,,.+ ^, 8'"I,% 8 A P "..+ l,2 "2 % [ ] * P 8,;K 9 % g b"k 7 '%A B ) 4", ; * ;A ", "\Q *. t k ( k ) ' ) /) * B* * %&

12 B* * %& %&, [2] Blatt H., Middleton G. V., Murray, R. G., "Origin of sedimentary rocks", (2nd edition), PrenticeHall Inc. New Jersey, (98) 782. [2] ang Q., Morse J.., "Pyrite formation under conditions approximating those in anoxic sediments I. Pathways and morphology", Marine hemistry 2 (996) [22] Rickard D., "Kinetics of pyrite formation by the H2S oxidation of iron (II) monosulfide in aqueous solutions between 2 and 2º: the rate equation ", Geochimica et osmochimica Acta 6 (997), 34. [23]Howarth R.., "Pyrite: Its rapid formation in a salt marsh and its importance to ecosystem metabolism", Science 23 (979), 49. [24] Raiswell R., Berner R. A., "Pyrite formation in euxinic and semieuxinic sediments" American Journal of Science 28 (98) [2] Schmitt J. G., "Description and interpretation of silicified skeletal material from the Park ity Formation (Permian) of yoming", M.S. thesis, University of yoming, Laramie, (979) 84.,K 2 8,, sequences", In: A. Iijima and Hein, J. R. and Siever, R. eds. Siliceous deposits in the Pacific region, Elsevier Sci. Pub. o., Amsterdam, (983) 243. [4] Daley R. L., Boyd D.., "The role of skeletal microstructure during Selective Silicification of Brachiopods", Journal of Sedimentary Research 66, (996) 62. [] Adams A.E., Mackenzie.S., Guilford., 984, "Atlas of sedimentary rocks under the microscope", Longman (984) 4. [6] Berner R.A., "Sedimentary pyrite formation", American Journal of Science 268 (97) 23. [7] Lovley D.R., "Dissimilatory Fe (III) and Mn (IV) reduction", Microbiological Reviews (99) [8] Sweeney R.E., Kaplan I.R., "Pyrite framboid formation: laboratory synthesis and marine sediments", Economic Geology 68 (973) [9] Passier H. F., Middelburg J. J., de Lange G. J., Bottcher M.E., "Pyrite contents, microtextures, and sulfur isotopes in relation to formation of the youngest eastern Mediterranean sapropel", Geology 2 (997) 9 22.