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

在金星上，所有玄武岩岩浆活动都是板内活动，我建议通过应用被称为大火成岩省（LIPs）的陆地板内事件的概念，为金星的BAT （Beta Atla Themis）区域的岩浆记录提供新的见解。就岩浆特征（羽状规模的火山大厦）的丰富程度、裂谷的规模和相对年轻的年龄而言，BAT是金星上最重要的区域。由于体积巨大（高达数百万立方公里），持续时间短（通常在不到100万年的时间内就位），陆地上的LIPs及其区域堤群与地幔深处产生的羽流有关，并与超级大陆的分裂有关。我建议将陆地LIP记录中的几个关键概念应用于金星的板内岩浆活动：1)区域地层标志。鉴于它们的区域范围（半径可达3000公里）和就位时间短，地球和金星上的主要岩脉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元的相对年龄。2)单位相关性。在地球上，侵蚀作用和板块构造已经将岩石破碎成广泛分离的单元（岩脉、岩基、层状侵入岩、残余洪水玄武岩以及相关的碳酸盐和金伯利岩），这些单元可以用U-Pb地质年代学进行对比。据预测，在金星上，通过对岩脉群及其与其他单元的相互作用的详细测绘，单元（火山建筑、运河、盾域、岩脉群、平原单元）可以类似地分组为离散的大范围板内事件（LIP规模）。3)热点曲目。随着岩浆中心的确定和它们的相对年龄的评估，应该有可能确定任何标记热点路径的区域趋势。4)唇部和裂谷。比较岩脉群与裂谷的横切关系，有助于了解裂谷作用的时间和持续时间。考虑到长达1万公里的裂缝规模，这一点尤为重要。方法是使用遥感数据（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），并应用行星科学界使用的图像处理方法以及关注β -阿特拉-忒弥斯（BAT）区域的新方法。计划招收一名博士和两名硕士研究生，总体目标是对BAT地区的岩浆历史进行全面评估，将岩脉群（地堑-裂缝系统）记录与该地区的裂谷和火山特征（火山大楼、大型熔岩流场、大型日冕、盾状平原和运河）的测绘结合起来。

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).