Mare domes, small shield volcanoes typically <∼30 km diameter, are part of the spectrum of lunar volcanic features that characterize extrusive basalt deposits. We used new spacecraft data to document these in Mare Tranquillitatis, among the oldest maria and the site commonly interpreted as an ancient degraded non-mascon impact basin. We found 283 known and suspected mare domes, with the majority (n = 229) concentrated on a broad, ∼450 km circular topographic rise in eastern Mare Tranquillitatis. The domes (median diameter 5.6 km, height 68 m, volume 0.7 km³) contain summit pits (74%; median diameter 0.8 km), and exhibit minor compositional variability between domes and surrounding flows, suggesting that domes both supply and are embayed by these flows. Based on their characteristics and associations, we interpret the small shield volcanoes to have been built from individual low-volume (<∼10–100 km³), low volatile content, short duration, cooling-limited eruptions. The ∼450 km broad volcanic rise is ∼920 m high (volume ∼1.6 × 10⁵ km³) and is interpreted to be built from multiple occurrences of small shield eruptions, a shield plains volcanism style. This implies a shallow mantle source region capable of supplying distributed dike-emplacement and eruption events over an area of 1.75 × 10⁵ km² early in mare volcanism history (∼3.7 Ga). The difference between Mare Tranquillitatis and younger mare-filled mascon basins is attributed to the more ancient thermal state and crustal structure of the viscously relaxed Tranquillitatis basin, and a shallower broad magma source region present in earlier lunar thermal history.

中文翻译：

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Mare Tranquillitatis 中的 Mare Dome：识别、表征和对它们起源的影响

马雷穹顶，通常小于 30 公里直径的小型盾状火山，是表征喷出玄武岩沉积物的月球火山特征谱的一部分。我们使用新的航天器数据记录了 Mare Tranquillitatis 中的这些，这是最古老的玛丽亚和通常被解释为古代退化的非马斯康撞击盆地的地点。我们发现了 283 个已知和疑似的母马穹顶，其中大多数 ( n  = 229) 集中在 Mare Tranquillitatis 东部一个广阔的、约 450 公里的圆形地形隆起上。圆顶（中径 5.6 公里，高 68 米，体积 0.7 公里³) 包含顶峰坑 (74%；中值直径 0.8 公里)，并且在圆顶和周围流之间表现出较小的成分变化，表明圆顶既供应又被这些流包围。根据它们的特征和关联，我们将小型盾状火山解释为由单个小体积（<~10-100 km ³）、低挥发分、持续时间短、冷却受限的喷发建造而成。约 450 公里宽的火山隆起高约 920 米（体积约 1.6 × 10 ⁵  km ³），被解释为由多次发生的小盾状火山喷发、盾状平原火山作用形成风格。这意味着浅地幔源区能够在海马火山活动历史早期（~3.7 Ga）的1.75 × 10 ⁵  km ²区域内提供分布式岩脉侵位和喷发事件。Mare Tranquillitatis 和年轻的充满母马的 mascon 盆地之间的差异归因于粘性松弛的 Tranquillitatis 盆地更古老的热状态和地壳结构，以及较早的月球热历史中存在的较浅的宽岩浆源区。