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瑶坑岩体位于浙闽交界的苍南县马站镇北侧 ,侵入于早白垩世石帽山群下组地层中。岩石发育典型的文象结构和晶洞构造 ,含有特征的钠铁闪石碱性铁镁矿物 ,主要矿物组合为石英 +条纹长石 +钠铁闪石 +黑云母 +萤石、锆石。化学成分上 ,该岩体富硅、碱 ,贫钙、镁 ,分异指数和氧化指数高 ,富Rb、Th、Ga,贫Sr、Ba,Ga/Al比值大 ,富轻稀土 ,Nb、Zr、Hf等高场强元素含量高 ,Cr、Co、Ni、V等过渡族元素显著亏损 ,并具强烈的铕负异常。上述特征与典型碱性花岗岩十分相似。根据对岩石地质地球化学特征的综合分析 ,并通过与区内魁歧、桃花岛岩体的广泛对比 ,确定瑶坑岩体为浙闽沿海晚中生代岩浆活动带内产出的又一典型的后造山碱性花岗岩。
Yao crater is located at the northern side of Mazhan Town, Cangnan County, where the Zhejiang-Fujian border was located. It intruded into the lower member of the Early Cretaceous Huamaoshan Group. The typical textural structure and geode structure of rock development include the characteristic iron-feldspar alkaline iron-magnesium minerals. The main mineral assemblages are quartz + stripe feldspar + sodium iron-iron ore + biotite + fluorite and zircon. In terms of chemical composition, the rock mass is rich in silicon, alkali, calcium, magnesium, high in dissimilarity index and oxidation index and rich in Rb, Th, Ga, lean Sr, Ba, Ga / Al, , Hf elements such as high field strength elements, Cr, Co, Ni, V significant loss of transitional elements, and a strong negative anomaly of europium. The above features are very similar to typical alkaline granites. Based on the comprehensive analysis of geologic and geochemical characteristics of rocks, and by extensive comparison with the Qufu and Taohua Island intrusions in the area, it is confirmed that Yaohang pluton is another typical post-Mesozoic magmatism belt produced in the Late Mesozoic along Zhejiang-Fujian coast Alkaline granite.