Laiwu hydrothermal metasomatic iron deposit is located at contact zone of Ordovician carbon-ate rock (Majiagou Formation摘要莱芜接触交代－热液铁矿赋存于奥陶系马家沟组碳酸盐岩与燕山晚期闪长岩的接触带及其附近。
Apatite fission track ages of three diorite samples is range from (78±) Ma to (9±) Ma, and the lengths of horizontal con裂变径迹年龄为(78±)—(9±)Ma,平均径迹长度为( .±.)—( .±. )μm。