Petrogenesis of basanite-phonolite series of an oceanic intraplate volcano: combining experimental data and field observations

响岩是碱性、硅质不饱和岩浆的分化端员，通常出现在大洋和大陆板内火山。尽管它们在全球范围内发生，但很少有人知道碱性岩浆在哪里，如何以及为什么在某些地方分化为响岩熔体，而不是在其他地方。只有少数实验研究的热力学条件和机制的响岩已进行，但它们的普遍适用性是有限的，由于大的组成范围的响岩。为了更好地了解碱性熔体的分化，我们提出了相平衡实验和详细的现场调查相结合的富钛玄武岩响岩系列的拉帕尔马，加那利群岛。拉帕尔马非常适合进行这样的研究，因为地质背景众所周知，而且熔岩和捕虏体覆盖了广泛的成分谱，已经得到了很好的研究。该研究的主要目标是限制拉帕尔马演化岩石形成和可以形成的条件（压力，温度，熔体和流体成分）的范围。由于拟议的项目涉及基本的岩石成因过程，预期的结果将不仅适用于拉帕尔马，而且适用于其他碱性地区和来自其他大地构造环境的岩浆。

Phonolites are differentiated end-members of alkalic, silica-undersaturated magmas that commonly occur at oceanic and continental intraplate volcanoes. Despite their global occurrence, little is known as to where, how, and why alkalic magmas differentiate to phonolitic melts at some places but not at others. Only few experimental investigations of thermodynamic conditions and mechanisms of phonolite formation have been carried out, but their general applicability is limited due to the large compositional range of phonolites. To better understand the differentiation of alkalic melts, we propose a combination of phase equilibria experiments and detailed field investigations of the Ti-rich basanite-phonolite series of La Palma, Canary Islands. La Palma is well suited for such a study because the geological background is well known and because lavas and xenoliths cover a wide compositional spectrum and are already well investigated. The major goal of the study is to constrain the range of conditions (pressure, temperature, melt and fluid composition) under which evolved rocks from La Palma have formed and can form. Because the proposed project deals with fundamental petrogenetic processes, the expected results would be relevant not only for La Palma but also for other alkalic provinces and magmas from other geotectonic settings.