Constraints on the origin of zonation of the granite complexes in the Fichtelgebirge (Germany and Czech Republic): evidence from a gravity and geochemical study
Constraints on the origin of zonation of the granite complexes in the Fichtelgebirge (Germany and Czech Republic): evidence from a gravity and geochemical study
复制标题
菲希特尔山脉（德国和捷克共和国）花岗岩杂岩带起源的限制：来自重力和地球化学研究的证据
DOI：
10.1007/pl00014669
复制
发表时间：
1997
期刊：
影响因子：
--
通讯作者：
G. Morteani
中科院分区：
文献类型：
--
作者：
L. Hecht;J. Vigneresse;G. Morteani
摘要：花岗岩体的成分分带是一个普遍特征，但分带的空间变化却很少被详细研究。建议如果将成分分区与根区（即深处的花岗岩形状）联系起来考虑，就会出现重要的附加信息。对海西期 Fichtelgebirge 花岗岩进行了地球化学和重力联合研究，该花岗岩由较古老的侵入杂岩 (OIC) 和较年轻的侵入杂岩 (YIC) 组成。 OIC 和 YIC 在岩浆成因、分异模式、深部花岗岩杂岩形状以及与根区相关的分带模式方面彼此不同。 OIC 显示正常的成分分区，而 YIC 则相反（YIC-1）和正常分区（YIC-2）。 OIC和YIC的总体分带格局是单批岩浆多次注入和岩浆侵位过程中原位分异共同作用的结果。除了一般的分带模式外，YIC 各个花岗岩体的局部分带是由侧壁结晶作用引起的，产生了分化程度较低的边缘相（G2）和分化程度较高的核心相（G3 和 G4）。有人认为，菲希特尔山花岗岩复合体的复杂分带模式反映了岩浆输出速率（部分受其流变特性控制）与变形速率（为岩浆侵位提供空间）之间的相互作用。
Abstract Compositional zoning of granitic plutons is a common feature, but the spatial variation of zoning is rarely studied in detail. It is suggested that important additional information can emerge if the compositional zoning is regarded with relation to the root zones, i.e. with the granite shape at depth. A combined geochemical and gravity investigation was performed on the Hercynian Fichtelgebirge granites, which are composed of an older intrusive complex (OIC) and younger intrusive complex (YIC). The OIC and YIC are distinct from each other with respect to magma origin, differentiation pattern, shape of the granite complexes at depth and the zonation pattern in relation to the root zone. The OIC shows normal compositional zoning, whereas the YIC both reverse (YIC-1) and normal zoning (YIC-2). The general zonation pattern of the OIC and the YIC is the result of a combination of multiple injections of single magma batches and in situ differentiation during magma emplacement. In addition to the general zonation pattern, local zonation in individual granite bodies of the YIC was caused by sidewall crystallisation producing a less-differentiated marginal facies (G2) and a more-differentiated core facies (G3 and G4). It is suggested that the complex zonation patterns of the Fichtelgebirge granite complexes reflect interactions between the rate of magma output which is partly governed by their rheological properties and the rate of deformation which provides the room for the magma to be emplaced.