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锡石原位微区U-Pb同位素测年，样品制备简单，具有高空间分辨率、高性价比、高效率等显著优势，是锡多金属矿床直接定年的有效手段。然而，基体效应的影响和标样的缺乏是制约该方法发展的关键。本次研究在He做载气以及加入不同辅助气（N2、水蒸气）条件下使用锆石作为外部标准物质对锡石标准和样品进行元素、同位素分馏校准，并采用Tera-Wasserburg图解法和207Pb法对普通铅进行校正。分析结果显示，氮气和水蒸气的引入，可以不同程度的提升Pb、U信号强度；3个不同的锡石标准和样品在He做载气及不同辅助气（N2、水蒸气）条件下获得的Tera-Wasserburg U-Pb下交点年龄及207Pb法普通铅校正后的206Pb/238U加权平均年龄在误差范围内都与文献报道值一致，并未发现明显基体效应的影响，显示采用锆石标准物质对不同类型锡矿床的锡石样品进行原位LA-ICP-MS U-Pb定年是可行的。

Diabase dyke swarms are widespread in the East Tianshan and Beishan regions. LA-ICP-MS zircon U-Pb ages of these diabase vary from 305 Ma to 278 Ma, showing that these dykes were formed during Late Carboniferous-Early Permian magmatism. All diabase samples are subalkali calc-alkali, characterized by slight LREE and LILEs enrichment, and weak negative Ti, Nb and Ta anomalies. The diabase samples have positive e(Nd)(t) values (>+3), high Sr isotopic compositions (initial 87Sr/86Sr values=0.7030–0.7097), and large variation of Pb isotopic compositions, indicating they were derived from a deplete mantle source. Regional geology and geochemistry evidences indicate that these diabase dyke swarms were generated in a lithosphere extensional setting and had the same magma sources. Initial magmas may be a mixture of depleted asthenosphere mantle and enriched lithospheric mantle during rapid magma ascending.

Late Mesozoic volcanic-subvolcanic rocks and related iron deposits, known as porphyry iron deposits in China, are widespread in the Ningwu ore district (Cretaceous basin) of the middle—lower Yangtze River polymetallic ore belt, East China. Two types of Late Mesozoic magmatic rocks are exposed: one is dioritic rocks closely related to iron mineralization as the hosted rock, and the other one is granodioritic (-granitic) rocks that cut the ore bodies. To understand the age of the iron mineralization and the ore-forming event, detailed zircon U-Pb dating and Hf isotope measurement were performed on granodioritic stocks in the Washan, Gaocun-Nanshan, Dongshan and Heshangqiao iron deposits in the basin. Four emplacement and crystallization (typically for zircons) ages of granodioritic rocks were measured as 126.1±0.5 Ma, 126.8±0.5 Ma, 127.3±0.5 Ma and 126.3±0.4 Ma, respectively in these four deposits, with the LA-MC-ICP-MS zircon U-Pb method. Based on the above results combined with previous dating, it is inferred that the iron deposits in the Ningwu Cretaceous basin occurred in a very short period of 131–127 Ma. In situ zircon Hf compositions of eHf(t) of the granodiorite are mainly from –3 to –8 and their corresponding 176Hf/177Hf ratio are from 0.28245 to 0.28265, indicating similar characteristics of dioritic rocks in the basin. We infer that granodioritic rocks occurring in the Ningwu ore district have an original relationship with dioritic rocks. These new results provide significant evidence for further study of this ore district so as to understand the ore-forming event in the study area.

The Xianghualing Sn-polymetallic orefield in Hunan Province, southern China, is a large-size tin orefield. Although numerous studies have been undertaken on this orefield, its genesis, mineralization age, and tectonic setting are still controversial, mainly because of the lack of reliable geochronological data on tin mineralization. The 40Ar/39 Ar stepwise heating dating method was first employed on muscovite from different deposits in this orefield. The muscovite sample from the Xianghualing Sn-polymetallic deposit defines a plateau age of 154.4±1.1 Ma and an isochron age of 151.9±3.0 Ma; muscovite from the Xianghuapu W-polymetallic deposit yields a plateau age of 161.3±1.1 Ma and an isochron age of 160.0±3.2 Ma; muscovite from the Jianfengling greisen-type Sn-polymetallic deposit gives a plateau age of 158.7±1.2 Ma and an isochron age of 160.3±3.2 Ma. The tungsten-tin mineralization ages in the Xianghualing area are therefore restricted within 150–160 Ma. The tungsten -tin mineralization in Xianghualing occurred at the same time as the regional tin-tungsten mineralization including the Furong tin orefield, Shizhuyuan tungsten-tin polymetallic deposit and Yaogangxian tungsten-polymetallic deposit. Thus, the large-scale tungsten-tin metallogenesis in South China occurring at 160-150 Ma, probably is closely related to asthenospheric upwelling and crust-mantle interaction under a geodynamic setting of crustal extension and lithosphere thinning during the transformation of tectonic regimes during the Mid-Late Jurassic.