Geochemistry and Provenance of Basaltic Clasts within Volcaniclastic Debris Flows, East Mariana Basin, Deep Sea Drilling Project Site 585
Geochemistry and Provenance of Basaltic Clasts within Volcaniclastic Debris Flows, East Mariana Basin, Deep Sea Drilling Project Site 585
复制标题
东马里亚纳盆地深海钻探项目现场 585 火山碎屑流中玄武岩碎屑的地球化学和物源
DOI：
10.2973/dsdp.proc.89.115.1986
复制
发表时间：
1986
影响因子：
1.3
通讯作者：
P. Floyd
中科院分区：
文献类型：
--
作者：
P. Floyd
从海山火山碎屑流中提取了卵石大小的玄武岩和玻璃碎屑，并对包括稀土在内的各种微量元素进行了分析，以确定它们的成因关系和来源。所有碎屑都起源于沉积改造之前相对较浅的海底熔岩流，并经历了轻微的低品位蚀变。它们被划分为三个岩石群(A、B和C)，以不同的斑晶组合和不相容元素的丰度和比例为特征。A组(585孔碎屑)为透明碎屑岩，呈橄榄石标准，有别于其他碎屑岩，具有过渡玄武岩或碱性玄武岩的元素不相容特征。B组和C组(585A孔碎屑)是石英规范的、可变的斜长石-单斜辉石-橄榄叶状拉斑玄武岩，具有基本相似的高度不相容元素的比例和轻稀土元素的富集型式(计时标准化)。B和C组内的变化是由观察到的斑晶相的低压分馏控制的，而每一组的最原始成分可能与共同来源的可变部分熔融有关。碎屑具有板内化学特征，尽管相对于与海洋热点有关的火山(如夏威夷拉斑玄武岩)，它们的大多数不相容元素都略有贫化。与亏损的大洋中脊玄武岩源区相比，源区富含所有不相容元素。
Pebble-sized basaltic and glassy clasts were extracted from seamount-derived volcaniclastic debris flows and analyzed for various trace elements, including the rare earths, to determine their genetic relationships and provenance. All the clasts were originally derived from relatively shallow submarine lava flows prior to sedimentary reworking, and have undergone minor low-grade alteration. They are classified into three petrographic groups (A, B, and C) characterized by different phenocryst assemblages and variable abundances and ratios of incompatible elements. Group A (clast from Hole 585) is a hyaloclastite fragment which is olivine-normative and distinct from the other clasts, with incompatibleelement ratios characteristic of transitional or alkali basalts. Groups B and C (clasts from Hole 585A) are quartz-normative, variably plagioclase-clinopyroxene-olivine phyric tholeiites, all with essentially similar ratios of highly incompatible elements and patterns of enrichment in light rare earth elements (chrondrite-normalized). Variation within Groups B and C was governed by low-pressure fractionation of the observed phenocryst phases, whereas the most primitive compositions of each group may be related by variable partial melting of a common source. The clasts have intraplate chemical characteristics, although relative to oceanic hot-spot-related volcanics (e.g., Hawaiian tholeiites) they are marginally depleted in most incompatible elements. The source region was enriched in all incompatible elements, compared with a depleted mid-ocean-ridge basalt source.
影响因子：
3.5
作者：
J. Pearce;M. Norry
通讯作者：
J. Pearce;M. Norry