Magmatic history of the BAT region of Venus: new constraints from the dyke swarm record

在金星上，所有的玄武岩岩浆活动都是板内的，我建议通过应用为大火成岩省(LIP)这类陆地板内事件而开发的概念，为金星的BAT(Beta Atla Themis)地区的岩浆记录提供新的见解。蝙蝠是金星上最重要的区域，因为它的岩浆特征(羽状火山建筑物)的丰富性，裂谷的规模和相对年轻的年龄。 由于体积巨大(高达数百万立方千米)和持续时间短(通常不到一百万年)，陆地嘴唇和它们的区域岩墙群与来自地幔深处的羽流联系在一起，并与超级大陆的解体有关。我建议将陆地LIP记录中的几个关键概念应用于金星上的板内岩浆作用：1)区域地层标志。考虑到它们的区域范围(半径可达3000公里)和侵位持续时间短，地球和金星上的主要岩墙群都是一个有效的区域地层标志，提供了它们切割和横切的单位的相对年龄。2)单元相关性。在地球上，侵蚀和板块构造将嘴唇碎裂成广泛分离的单元(岩墙、岩床、层状侵入体、残留的洪泛玄武岩以及相关的碳酸盐岩和金伯利岩)，可以用U-Pb年代学进行对比。据预测，在金星上，通过绘制岩墙群及其与其他单元的相互作用的详细地图，可以类似地将单元(火山建筑物、运河、盾牌、岩墙群、平原单元)归类为离散的大范围板内事件(嘴唇规模)。3)热点跟踪。随着岩浆中心的确定和它们的相对年龄的评估，应该有可能确定标有热点踪迹的任何区域趋势。4)嘴唇和裂痕。对比岩墙群和裂谷之间的横切关系，可以洞察裂谷形成的时间和持续时间。鉴于裂谷的规模，这一点尤其重要，长达10,000公里。 其方法是利用遥感数据(来自麦哲伦雷达航天器和目前的多传感器金星快车航天器)，并采用行星科学界使用的图像处理方法以及以Beta-Atla-Themis(BAT)区域为重点的新办法。 该计划有一名博士生和两名理科硕士学生，总体目标是对BAT地区的岩浆史进行全面评估，将岩墙群(地堑-裂隙系统)记录与该地区的裂谷和火山特征(火山建筑物、大型熔岩流场、大日冕、盾形平原和运河)相结合。

On Venus all basaltic magmatism is intraplate and I propose to provide new insights into the magmatic record of the BAT (Beta Atla Themis) region of Venus by applying concepts being developed for the class of terrestrial intraplate events known as Large Igneous Provinces (LIPs). The BAT is the most significant region on Venus in terms of the abundance of its magmatic features (plume-scale volcanic edifices), scale of rifting and relatively young age. With huge volumes (up to millions of cubic kilometres) and short duration (often emplaced in less than a million years), terrestrial LIPs and their regional dyke swarms are linked to plumes arising from the deep mantle, and associated with the breakup of supercontinents. I propose to apply several key concepts from the terrestrial LIP record to intraplate magmatism on Venus: 1) Regional Stratigraphic Marker. Given their regional extent (up to >3000 km in radius) and short duration of emplacement, major dyke swarms on both Earth and Venus are an efficient regional stratigraphic marker, providing relative ages with respect to the units they cut and are crosscut by. 2) Unit Correlation. On Earth, erosion and plate tectonics have fragmented LIPs into widely separated units (dykes, sills, layered intrusions, remnant flood basalts, and associated carbonatites and kimberlites) that can be correlated using U-Pb geochronology. On Venus, it is predicted that units (volcanic edifices, canali, shield fields, dyke swarms, plains units) can similarly be grouped into discrete large-extent intraplate events (of LIP scale)—through detailed mapping of dyke swarms and their interactions with other units. 3) Hotspot tracks. As magmatic centres are identified and their relative ages are assessed it should be possible to identify any regional trends marking hotspot trails. 4) LIPs and rifting. Comparison of crosscutting relationships between dyke swarms and rifts provide insight into the timing and duration of rifting. This is particularly important given scale of rifts, up to 10,000 km long. The methodology is to use remote sensing data (from the Magellan radar spacecraft and the current multi-sensor Venus Express spacecraft) and apply image processing methodologies used by the planetary science community as well as new approaches with a focus on the Beta-Atla-Themis (BAT) region. The plan is to have one PhD and two MSc students, with the overall goal to produce a comprehensive assessment of magmatic history in the BAT region that integrates the dyke swarm (graben-fissure system) record with mapping of rifts and volcanic features in the region (volcanic edifices, large lava flow fields, large corona, shield plains, and canali).