The main characters of the thermal fluid activity are recognized as follow : many types and stages of veins are widely developed ; vitrinite reflectivity of different areas varies apparently with the depth ; there was a high temperature field during the formation of the thermal fluid , meanwhile , the volcaniclastic rocks were modificated by the thermal fluid activity , for example , sericitization of plagioclase , chloritization of volcanic detritus in andesitic detris tuff ; in the tufaceous mud , the thermal fluid activity accelerates " maturating " of the organic carbon by heating ; and the trace elements show an anomaly in the wall rocks 同时，受热流体活动的影响，热流体对火山碎屑岩具有一定改造作用，如在安山质岩屑凝灰岩中，斜长石绢云母化、火山岩岩屑绿泥石化明显；在凝灰质泥岩中，热流体对围岩中有机碳具有明显的“催熟”加热作用，微量元素则出现异常现象。
