2nd Geochemical Investigation of the Aegean Volcanic Arc

本研究项目是根据“爱琴海火山弧的地球化学调查”项目(1993-1994)进行的。这些项目的目的是用火山挥发分地球化学法和火山地貌学方法研究爱琴海火山弧的岩浆活动。由于爱琴海弧以大陆(非洲)板块俯冲为特征，与大多数与大洋板块俯冲有关的火山弧不同，该弧在弧火山比较研究中发挥着重要作用。他们与一名希腊调查员一起对希腊的火山和地热区进行了实地监测。调查地区是Makedonia(希腊北部)的地热区，以及沿火山前缘的尼塞罗斯火山和桑特里尼火山。在Makedonia，对温泉周围的地热进行了监测，并为…收集了温泉气体和水。更多的元素和同位素分析。由于该地区远离火山前缘，研究它们是否含有来自爱琴海弧形岩浆的岩浆挥发物是很重要的。经过对1993年样品的研究，尼塞罗斯火山的火山气显示出少量的Ne同位素异常。如果这一点得到证实，这将是第一次或第二次在弧形样品中发现Ne同位素异常。为了确定Nisyros火山不同陨石坑中的Ne同位素异常，采集了不同火山口的气体样品，测定了稀有气体和二氧化碳中碳的化学成分和同位素比值。同时测定了水样的化学成分和氢、氧同位素组成。根据气体样品的(N_2/Ar)和(He/Ar)系统学分析，爱琴海弧区形成了与世界上其他弧区不同的关系。这可能与不同的俯冲板块有关：爱琴海弧内的大陆板块和其他许多弧区的海洋板块。1995年，一名希腊考察员于9月19日至10月3日访问日本进行合作。较少

This research program follows the 2 years' program "Geochemical Investigation of the Aegean Volcanic Arc" (1993-1994). The purpose of these programs is to investigate magmatic activities in the Aegean volcanic arc by means of both geochemical approach of volcanic volatiles and volcano-geomorpholog-cal approach. Because the Aegean arc is characterized by the continental (African) plate subduction, in contrast to most of volcanic arcs related to oceanic plate subduction, this arc plays an important role for comparative study of arc volcanism.Five Japanese investigators visited Greece during 18 August and 13 September 1995. They carried out field surveillance of volcanic and geothermal areas in Greece with a Greek investigator. The investivated areas are geothermal areas in Makedonia (Northern Greece) and Nisyros and Santrini volcanoes along the volcanic front. In Makedonia, geothermal surveillance around hot spring sites was carried out and hot spring gases and waters were collected for … More elemental and isotope analyzes. As this region is far from the volcanic front, it is important to study whether or not they contain magmatic volatiles derived from Aegean arc magma. After previous studies of 1993 samples, volcanic gas from Nisyros volcano showed a little neon isotope anomaly. If this is confirmed, this is the first or 2nd discovery of neon isotope anomaly in arc samples. In order to confirm neon isotope anomaly, several gas samples from different craters of Nisyros volcano were collected.For gas samples, chemical composition and isotope ratios of rare gases and carbon in CO_2 were determined. While, chemical composition and H and O isotope compositions were determined for water samples. According to (N_2/Ar) vs. (He/Ar) systematics of gas samples, the Aegean arc forms different relationship from other arcs in the world. This may be related to the different subducting slabs ; continental in the Aegean arc and oceanic in many other arcs.In 1995 program, a Greek investigator visited Japan from 19 September to 3 October for collaboration. Less