Experimental Study of Feldspar Dissolution by Acetic Acid at Different Burial Temperatures

In order to evaluate the effect of organic acids on the dissolution of feldspar at different burial temperatures，perthite dissolution by acetic acid experiments were run at 650C，2 OMpa;75℃， 3 OMpa;95℃，30Mpa and 1300C，30Mpa.The experimental results are as follows: 1)Postassium，sodium and aluminium were preferentially released，but silicon was last released in feldspar dissolution. 2)Under the conditions of relatively low temperature，the ratio of released cations was far from the chemical composition of dissolved feldspar，but when increasing temperature，it was gradually close to the composition. 3 ) In perthite，albite is more easily to be decomposed than K一feldspar. 4)Temperature effect of silicon is 5.4，8.6 and 9.2 times as large as sodium，aluminium and potassium，respectively. 5)Compared with aluminium，most silicon released at relatively high temperature (more than 95℃).It implies that the precipitation of authigenic SiO₂ minerals which blocked up most of porosity occurred at the burial depth with geotemperature mare than 95 C.