关键词: 晚中生代侵入岩, 同位素地质年龄, 地质和地球化学特征, 构造背景, 安徽铜陵地区

Abstract: The Tongling district of Anhui Province is an important ore concentrating area in the tectonic-magmatic-metallogenic belt of
the middle and lower reaches of Yangtze River in eastern China. The copper-gold polymetallic deposits in this area are closely related
to the Late Mesozoic (Late Yanshanian) magmatism. Previous studies have suggested that the isotopic ages of intrusive rocks are
concentrated in the range of 147-135 Ma. Based on the new zircon U-Pb dating results, this study found that there are a small amount
of intrusions were formed between 132-124 Ma. Therefore, according to these new age data of the intrusive rocks, the magmatism
during the Late Mesozoic in the Tongling district can be divided into two stages, corresponding to Late Jurassic-Early Cretaceous and
Early Cretaceous, respectively. This paper has systematically studied the geological characteristics of the two stage intrusive rocks,
including rock types, occurrences and spatial distribution, and geochemical characteristics of major, trace and rare earth elements. By
comparing these two stage intrusive rocks with the volcanic-intrusive rocks in Ningwu and Luzong basins, it is concluded that the early
and the late stage magmatism were generated under a transitional setting from compression to extension and an extensional setting,
respectively. The late stage intrusive rocks were formed jointly by re-emplacement of magma from the early stage magma chamber and
magma from further partial melting of the deep crust. The significance of the mineralization related to the late stage intrusion can not be
ignored.

Key words: Late Mesozoic intrusive rocks, isotopic ages, geological and geochemical characteristics, tectonic setting, Tongling district of Anhui Province