JADEITIC ROCKS WITHIN HIGH-PRESSURE METAMORPHIC ZONE FROM NORTHEASTERN JIANGXI PROVINCE AND THEIR FORMING AND SURVIVING CONDITIONS

There is a close relation in time, space and origin between the NEJXO, NEJXDFZ and HFMZ from NEJXP which are located in and constrained by b oth Yangtze Craton and Cathaysia. These HPMRs principally include (i) Jd-Q-Ab schist, (ii) Jd-Ab schist, (iii) Jd-Ab schist, and (iv) Gl-sch ist. The Jd is nearly pure (Jd91-98). Jd surrounded by Ab is separated from Q and survived due to the reaction between Jd and Q, while Lw en circled by Ab remains as a pseudomorph composed of CZo + An. The miner als associated with Jd are Lw, Gl, Ab, Q, CZo, An, Pa, Il, Ru, Sp, Ap, and Zr. According to the textures, the mineral paragenesis is classif ied into four groups (i) PI-Am-Q, (ii) Jd-Lw-Gl-Q, (iii) CZo-An-Ab-Q, (iv) Ab-Ana-Ser-Ur, corresponding to (i) 1.0-0.93 Ga, 250 degrees C, 2 -3 x 10(8)Pa; (ii) 0.93-0.79 Ga, 300-350 degrees C, 5-12 x 10(8) Pa; ( iii) 0.79-0.223 Ga, 350-400-120 degrees C, 12-5-3 x 10(8) Pa; and (iv) <0.223 Ga, <120-50 degrees C, <3 x 10(8) Pa, in rime, temperature and pressure respectively. A clockwise P-T-I path is isothermal increasing in P (up to 45 km)-isothermal decreasing in P (up to 5 km)-nearly iso bar decreasing in T.