GENESIS OF NIUJUAN HOT-SPRING TYPE Ag (Au) DEPOSIT IN HEBEI PROVINCE

This deposit is one of important Ag deposits found recently in the north part of He-bei. In this paper basing on the work of predecessors and many geologic observtions of surface, producing area, drilling cores, from the genesis of siliceous breecia, the divide of ore-foroming stages, ore forming physio-chemical conditions, inclusion etc, authors discuss the genesis of this deposit and give a metallogenic model Ore-forming tempheratures of this deposit are relatively high (220 -350℃), metallogenic press are low (less than 260×10⁵Pa), the depth is 0. 42-0. 86km, the forming environment is the subsurface environment, the ore-forming fluid is of characters of low salinity (less than 3. 35wt% NaCl), rich in K⁺, Cl^-, F^-, SO₄^2-, poor in Na⁺, Ca²⁺, so it belongs to a typical hot spring type deposit.