13 3 V o l113, N o13 1 9 9 7 8 A CTA PETROLO G ICA S IN ICA A ug., 1997 Ξ M etam orph ism of A l-r ich Gne isses in Ta ihang M oun ta in Archean M etam orph ic Com plex L iu Shuw en and L iang H aihua ( 100871) (D ep artm ent of Geology, P ek ing U niversity B ej ing, 100871), Gt ( ) + St ( ) + P l ( ) + M s ( ) + B i ( ) + R u ( ) + Q z ( ) K2fs ( ); Gt+ Ged ( ) + B i+ P l+ Ilm ( ) + Co ( ) + Sill1 ( ) + Q z+ K2fs M s; H c+ K2fs+ Sill2 ( ) 680 018 GPa, 730 750 017GPa P 2T,, P 2T ( ITD ) P T t Abstract A l2rich gneisses in T aihang mountain A rchean m etamo rph ic comp lex are m ainly dis2 tributed in the low er part ofw anzi stratified rock series and the gneisses usually associate together w ith vari2 ous m arbles o r occurrence by stratified bodies in granitic gneisseṡ D epending on textural and m etamo rph ic reaction relationsh ip s of rock s, w e divide the evo lution of their m etamo rph ism into th ree stageṡ M ineral as2 sem blage in the early stage is garnet + stauro lite + p lagioclase + m uscove+ bio tite + quartz + rutile K2 feldspar; m ineral assem b lage in the m iddle stage is garnet + gedrite + sillim an ite1 (hair2sill) + b io tite + co rundum quartz + p lagioclase + ilm enite+ K2feldspar; m ineral assem blage in the later stage is hercynite + sillim anite2 (needle2sill) + K2feldspaṙ T h rough garnet2 bio tite thermom etry and internally consistent ther2 modynam ic calculation, w e get that garnet, stouro lite and rutile assem blage fo rm ed at 680 and 018 GPa, co rundum 2 and gedrite2p resent m ineral assem blage at a little P 2T space of 730 750 and about 017 GPa; T he temperature of sillim anite2 and hercynite2p resent m ineral assem blage are a little h igher than that of sec2 Ξ 1997201215, 1997205227. ( 49202025 49672153 ). : 1958 转 载
304 1997 ond association, yet p ressures are less than one of second assem blage. T he evo lution of above m ineral assem 2 blages and P 2T conditions constructs a clockw ise ITD 2type P 2T tpath. : P T t Key W ords: A rchean; A l2rich gneisses; m etamo rph ism; P T t trajecto ry; T aihang mountain : P588134 Classif ic. code: P588134, (, 1989), 2,,,,,, ( ) (, 1989),, (, 1982), 1 2800 2600M a (, 1989), ( 1), ( ), ( ),,, (, 1997),,, 2 2
13 3 : 305 1 : 11 ; 21 ; 31 ; 41 ; 51 ; 61 ; 71 ; 81 ; 91 ; 101 ; 111 ; 121 F ig11 Geo logical sketch of A rchean m etamo rph ic rock series in Fup ing area,,, 2,,,,, 2 2 1 10cm 2 S,, Ρ ( 2A )
306 1997,, ( ),, ( 2B ),, SiO 2 SiO 2 2,,, ( 2C),,,,, ( 2D ),,,,,,,,, 2 A. ; B ; C. ; D 1 ( ) : Gt ; Ilm ; Q z ; P l ; B i ; K2fs ; Sill ; Ged ; H c ; St ; M s ; Co ; F ig12 T extures in A l2rich gneisses
13 3 : 307,,,,,,, Gt+ St+ P l+ M s+ B i+ R u+ Q z K2fs; Gt+ Ged+ B i+ P l+ Ilm + Co+ Sill1 ( ) + Q z+ K2fs M s; H c+ K2fs+ Sill2 ( ) 31 311 ( 1), 1 (% ) T able 1 Chem ical compo sitions (% ) of rep resentative m inerals L 124H c L 121St L 121B i L 121Gt L 122B i L 122Gt L 122Ged L 121M s SiO 2 0108 25127 36122 36163 34112 36149 41177 42154 T io 2 5145 0156 1118 0100 2112 0112 0127 0188 A l2o 3 59122 52124 17126 21178 18104 21116 14157 32154 FeO 29159 14138 13177 28187 20129 29159 23138 4121 M no 0109 0129 0105 2100 0111 1175 0130 0102 M go 4176 2172 15149 7100 10120 7139 13171 4121 CaO 0102 0110 0110 2170 0107 3124 0171 0115 N a2o 0159 0115 0160 0136 0131 0119 1176 0179 K2O 0100 0104 9142 0109 10198 0103 0100 12129 100110 97186 94119 99137 96123 99194 96141 93192 Si 0100 3163 2167 2190 2163 2189 6130 2188 T i 0111 0106 0109 0100 0112 0101 0103 0105 A l 1191 8183 1164 2104 1164 1198 2159 2160 Fe 0169 1173 0197 1191 1131 1196 2195 0124 M n 0100 0104 0100 0113 0101 0112 0104 0100 M g 0119 0158 1154 0183 0101 0187 3108 0143 Ca 0100 0102 0102 0123 1117 0128 0112 0101 N a 0103 0104 0113 0106 0101 0103 0152 0110 K 0100 0100 0187 0101 0195 0100 0100 1106 O 4100 23100 11100 12100 11100 12100 23100 11100 :, 2; O ; H c, St, B i ; Gt, Ged, M s
308 1997, (FegFe+ M g) 01748 01751 Ca= 01099 01115, A l= 21383 21635, N a= 0148 0159 (Ca+ N a) B = 0158 0170< 1134,, Si= 6123 6145< 7, M gg(m g+ Fe) = 01511 01512, M gg(m g+ Fe) = 01473 01667, Fo ster (1960), A lm = 016071 016209, Pyr= 012476 012706, Gro = 0107387 010924, Spe= 013643 01471 X A n= 013531 013836, X A b= 016136 016304 Feg(Fe+ M g) 017798 017927, (H c) 312, ( ), ( ) 2, 016GPa 019GPa ( 2). 2 2 T able 2 T hermom etry of garnet2bio tite (GPa) ( ) lnkd1 T FS THS lnkd2 T im T im 1 L 121 L 122 016-415146 665 700-115049 677 656 019 678 712 690 669 016-410976 726 763-113659 728 704 019 740 777 742 718 : L 121 ; L 122 T FS Ferry and Spear (1978) 2, T HS Hodges and Spear (1982) 2, T im T im 1 In2 dares and M artibno le (1985) 2 ; kd1 kd2 2,, 013GPa, 681 737 50, L 12 1 Berm an (1988, 1991) P 2X H 2 O 681, P 2X H 2 O, 9Gro ( ) + 12Q z+ 8R t ( ) + 2St= 8 Ilm + 27A n ( ) + 4H 2O 2A nn ( ) + 3A n+ 3Q z= 2A lm ( ) + Gro+ 2K2fs+ 2H 2O 0182GPa X H 2 O = 016, P 2T 2X H 2 O A FM A K F Ged ( ) St+ B i+ Gt
13 3 : 309,, ( 3a),, A K F ( 3b), ( 3b) (1989),,,, 3 A FM (a) A K F (b) 2 F ig13 A FM (a) and A K F (b) diagram 313 P -T (, 1982), M s+ Q z= Sill+ K2fs+ H 2O 650 ( 4A ) X H 2 O, X H 2 O = 016, 700 700 4A M s+ Q z= Sill+ K2fs+ H 2O M s= Co + K2fs+ H 2O (V elde 1966),,,, 700, Berm an (1988, 1991) A nn ( ) + Co= M s + H c ( 4A ), 600, 017GPa, ( 4A ), 014 017GPa, 700 800 X H 2 O X H 2 O 0 015 100
310 1997, ( 4A ), R ichardson (1968), 690, 0135GPa, 0165 0172GPa (N ew ton, 1972),, L ang ( 1991),,,, P 2T 738 0172GPa, 016GPa 750 ( 4B ) ( 4 ), 4 A. ( ) ; B1 ( ) ; 2; A nn ; A lm ; F ig14 Phases relationsh ip s of A l2rich gneisses 4 P T t, 681 0182GPa ( 5 A ) 737, Ged+ St= Gt+ Q z+ H 2O ( 5 ) Ky ( ) = Sill St+ Ged+
13 3 : 311 Q z= A lm + Co rd+ H 2O ( 5 ) St+ Q z= A lm + Sill+ H 2O ( 5 ) ( 5 B ) M s+ Q z= Sill+ K2fs+ H 2O M s= Co + K2fs+ H 2O, A nn + Co = M s+ H c A nn + 3Co = 3H c+ 4K2fs+ 4H 2O ( 5 C ), A nn+ Co= H c+ M s A nn+ 3Co = 3H c+ 4K2fs+ 4H 2O ( 5 D ), P 2T 681 0182GPa ( 5 A ), P 2T 690 800, 0165 018GPa ( 5 B C ), P 2T 650 750, 0165GPa ( 5 D ), P 2T ITD P T t ( 5) 5 PT t 2 4; A P 2T ; B C, ; D P 2T ; P 2T ; F ig15 P T t trajecto ry of A l2rich gneisses PT t, (, 1997), 7 (1) Gt+ St+ P l+ M s+ B i+ R u+ Q z K2fs; Ged+ B i+ P l+ Ilm + Co + Sill1 ( ) + Q z+ K2fs Gt M s; H c+ K2fs+ Sill2 ( ) (2) P 2T 680 018 GPa, P 2T 690 800, 0165 018GPa, P 2T 650 750, 0165GPa (3) P 2T (ITD ) P T t, P T t
312 1997,, 80!. 1989.. :, 13 68,. 1982.. :, 211 238. 1997., ( ), 33 (3) ( ),,,,. 1989.., 19 : 3 152 Berm an R G. 1988. Internally consistent thermodynam ic data fo r the m inerals in the system N a2o 2K2O 2CaO 2M go 2FeO 2 Fe2O 32A l2o 32SiO 22T io 22H 2O 2CO 2. J. Petro l., 29: 445 522 Berm an R G. 1991. Thermobarom etry: using m ulti2equilibrium calculations: a new technique, w ith petro logical app lications. Canad. M ineral., 29: 833 856 Ferry J M and Spear F S. 1978. Experim ental calibriation of the partitioning of Fe and M g betw een bio tite and garneṫ Con2 trib. M ineral., Petrl., 66: 113 117 Hodges K V and Spear F S. 1982. Geo thermom etry, geobarom etry and the A l2sio 5 trip le po int at M ṫ M oo silauke, N ew H amp sh ires. Am. M ineral., 67: 1118 1134 Indares A. and M artibno le J. 1985. Bo itite2garnet geo thermom etry in the granulite facies: influence of T i and A l in bio tite. Am. M ineral., 70: 272 278 L ang H M. 1991. Q uantitative interp retation of w ithin2outcrop variation in m etamo rphic assem blage in stauro lite2kyanite grade m etapelites, Baltimo re, M aryland. Canad. M ineral., 29: 687 692 N ew ton R C. 1972. A n experim ental determ ination of the h igh2p ressure stability lim its of m agnasian co rdierite under w et and dry conditions. J. Geo l., 80: 398 420 R ichardson S W, Bell P M and Gilbert M C. 1968. Kyanite2sillim anite equilibrium betw een 700 1500 Am. J. Sci., 266: 513 541 V elde B. 1966. U pper stability of m uscovite. Am. M ineral., 51: 924 929