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由消减大陆边缘火山沉积岩与洋中脊和大洋岛的玄武岩对比可知，前者最明显的特征是高场强元素Ｎｂ、Ｔａ相对于大离子亲石元素Ｔｉ和轻稀土来说明显亏损。搞清这个问题的主要障碍是缺乏高场强元素（特别是Ｎｂ和Ｔａ）的高质量的分析数据，因为在大多数消减大陆边缘火山岩中其富集程度均很低。本文发表的是岛弧火山岩以及一些海底沉积物中Ｎｂ、Ｔａ的新分析结果。数据表明，Ｎｂ、Ｔａ亏损的岛弧火山岩的Ｎｂ／Ｔａ值，与大洋中脊火山岩的Ｎｂ／Ｔａ比值接近，基本上相当于球粒陨石值（Ｎｂ／Ｔａ约１７），而含钾质较高的岛弧火山岩具有较高的Ｎｂ／Ｔａ比值（达到３３）。笔者将这种高值视为来自俯冲板片的硅质熔体对岛弧地幔源的改造，而含钾质较少的岛弧岩石源区的富集则由于板片来源流体的加入
The most obvious feature of the former is that the high-field elements Nb and Ta are significantly depleted relative to the large ion lithophile elements Ti and LREE, as evidenced by the reduction of the basalts of the volcanic sedimentary rocks on the margin of the continental margin and the mid-oceanic ridges and oceanic islands. The main obstacle to this problem is the lack of high-quality analytical data for high-field elements (especially Nb and Ta), since most of the depleted continental marginal volcanic rocks are poorly enriched. This paper presents new results of the island arc volcanic rocks and some sea-bed sediments Nb and Ta. The data show that Nb / Ta values of Nb and Ta depleted island arc volcanics are close to those of mid-oceanic ridge volcanics and are basically equivalent to chondrite values (Nb / Ta ca. 17), whereas potassium-containing compounds High island arc volcanic rocks have a higher Nb / Ta ratio (up to 33). The authors consider this high value as a modification of the island arc mantle source from subducted slab siliciferous melt, while the enrichment of island arc source rocks with less potassium content is due to the addition of plate source fluids