洋岛玄武岩

通过岩石特征和地球化学分析，确定了盐边群荒田组火山岩组合为洋脊玄武岩、洋岛玄武岩、洋岛安山玄武岩系列，说明这是洋壳残片，即典型的蛇绿岩套。

The analysis of the geochemical and petrologic characteristics features shows that the assemblage of volcanic rocks is the series of middle ocean ridge basalt , ocean island basalt and ocean island andesite basalt , which implies that it is the relic of the ocean crust , i.e. typical ophiolites .

这些大陆玄武岩普遍具有类似洋岛玄武岩（OIB）的微量元素分布特征和相对亏损的Sr-Nd同位素组成。

These continental basalts are generally characterized by OIB-like trace element distribution patterns and depleted Sr-Nd isotope compositions .

PREMA（FOZO）则是洋岛玄武岩和溢流玄武岩公共端员。

PREMA ( FOZO ) is a popular end member of mantle for all ocean island and flood basalts , probably representing the lower mantle .

以其不相容元素比值，相当于Gough岛EMⅠOIB型洋岛玄武岩，其构造环境判别图进一步印证了海西期火山岩形成于洋岛碱性玄武岩环境。

Its contents are similar to those of EM ⅰ OIB from the Gough islands , and show ocean island alkaline basalt characteristics including the discriminant diagrams of tectonic settings for volcanics , which implies that the Hercynian volcanics were formed in tectonic environment of ocean island .

北带玄武岩属碱性玄武岩系列，南带玄武岩属拉斑玄武岩系列；北带玄武岩富集Rb、Th、Ta、Nb，与洋岛碱性玄武岩稀土曲线一致；

The basalt in the north zone belongs to the alkaline basalt series , enriched in Rb , Th , Ta and Nb , showing that its characteristics are consistent with those of oceanic island basalt .

进一步的地球化学研究表明，这套玄武岩为洋岛型玄武岩（OIB）和洋中脊型玄武岩（MORB）的组合。

Based on more geochemical signatures , two types of basalt are recognized , namely , ocean island basalt ( OIB ) and mid ocean ridge basalt ( MORB ) .

据构造环境判别图判别，安山岩类又具洋岛碱性玄武岩的特征。

In the light of tectonic discrimination diagrams , the andesite is characterized by alkaline basalt of ocean-island setting .

N-MORB标准化蛛网图和球粒陨石标准化图解表明，本区洋岛拉斑玄武岩和洋岛碱性玄武岩具有共同的岩浆源区。

In addition , the N-MORB-normalized spider diagram and the Chondrite-normalized REE pattern show that the two kinds of rocks were generated from the same parental magmatic source .

基性熔岩稀土元素分布模式既有洋脊玄武岩的平坦曲线，又有轻稀土富集型的夏威夷等洋岛玄武岩的特征，反映该蛇绿岩带混杂着洋壳残骸和洋岛碎块。

The REE partition pattern of basic lava not only consists of flat curve of mid oceanic ridges basalt but also includes the characteristic of Hawaii oceanic island basalt with LREE abundant type , which reflects this ophiolitic belt mixed ocean crust wrecked with oceanic island fragment .