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

金星 BAT 区域的岩浆历史：岩墙群记录的新限制

• 批准号: RGPIN-2014-04258
• 负责人: Ernst, Richard
• 金额: $ 2.19万
• 依托单位: Carleton University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2015
• 资助国家: 加拿大
• 起止时间: 2015-01-01 至 2016-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=587697
• 关键词: Magmatic; history; BAT; region; Venus

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).

在金星上，所有玄武岩岩浆作用都是板内的，我建议通过应用为称为大型火成岩省（LIP）的陆地板内事件类别开发的概念，为金星 BAT（Beta Atla Themis）区域的岩浆记录提供新的见解。就其丰富的岩浆特征（羽状火山建筑物）、裂谷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）且持续时间短（通常不到一百万年），陆地唇形岩及其区域岩墙群与深部地幔产生的羽流有关，并与超大陆的分裂有关。我建议将陆地 LIP 记录中的几个关键概念应用于金星上的板内岩浆作用：1）区域地层标记。鉴于其区域范围（半径达>3000公里）和侵位持续时间短，地球和金星上的主要堤坝群都是有效的区域地层标记，提供了它们切割和横切的单位的相对年龄。 2）单位相关性。在地球上，侵蚀和板块构造已将 LIP 破碎成广泛分离的单元（堤坝、岩床、层状侵入体、残余溢流玄武岩以及相关的碳酸岩和金伯利岩），这些单元可以使用 U-Pb 地质年代学进行关联。在金星上，通过堤坝群及其与其他单元的相互作用的详细绘图，预测单元（火山建筑物、运河、盾构场、堤坝群、平原单元）可以类似地分组为离散的大范围板内事件（LIP 尺度）。 3) 热点轨道。当岩浆中心被识别并评估它们的相对年龄时，应该可以识别标记热点路径的任何区域趋势。 4）嘴唇和裂痕。 比较堤坝群和裂谷之间的横切关系可以深入了解裂谷的时间和持续时间。考虑到裂谷的规模长达 10,000 公里，这一点尤其重要。 该方法是使用遥感数据（来自麦哲伦雷达航天器和当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重点关注贝塔-阿特拉-忒弥斯（BAT）区域的新方法。 该计划是培养一名博士生和两名硕士生，总体目标是对 BAT 地区的岩浆历史进行全面评估，将堤坝群（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、大型日冕、盾构平原和运河）测绘相结合。