Mid-Crustal Anatexis and Hybridization Associated With Mafic Plutonism in the Bindal Batholith, Norwegian Caledonides

巴内斯山造山事件通常伴随着花岗岩浆侵位，花岗岩浆的起源目前尚有争议。在许多情况下，花岗岩浆是由地幔衍生的高温岩浆与地壳岩石结合而成的混合体。在其他情况下，花岗岩浆显示了纯粹地壳起源的同位素和元素证据。地壳起源通常需要传递足以导致融化的热量。许多研究人员认为，从地幔岩浆中提取的热量是这种地壳融化的主要来源。在挪威中北部的Velfjord地区，一群地幔衍生的深成岩体几乎被一层花岗岩皮包围，这些花岗岩显然是由当地熔融形成的；热量是由地幔衍生的深成岩体的侵入提供的。由于规模较小，这一环境为研究地壳融化与较热岩浆提供的热量之间的关系提供了一个极好的机会。研究的重点将是确定熔融条件、熔融的热需求、花岗岩熔体的流动性以及地壳熔体与其岩浆“热源”之间的化学相互作用。这一结果将为地壳尺度上发生的熔融提供直接的类比。

9814280BarnesMountain building events are commonly accompanied by emplacement of granitic magmas, the origins of which are currently in debate. In many cases, granitic magmas are hybrids which form when hot magmas derived from the mantle combine with crustal rocks. In other cases, granitic magmas show isotopic and elemental evidence of a purely crustal origin. A crustal origin typically requires transfer of heat sufficient to cause melting. Many investigators call on heat extracted from hot, mantle-derived magmas as the primary source of such crustal melting. In the Velfjord area of north-central Norway, a group of mantle-derived plutons are nearly surrounded by a rind of granitic rocks that were apparently derived by local melting; heat was provided by intrusion of the mantle-derived plutons. Because of the small scale, this setting provides an excellent opportunity to investigate the relationship between crustal melting and heat provided by hotter magmas. Research will focus on determination of the conditions of melting, the thermal requirements for melting, mobility of the granitic melts, and chemical interaction between the crustal melts and their magmatic "heat source". The results will provide a direct analogue to melting that occurs on a crustal scale.