Santa Maria is the oldest island in the Azores, formerly belonging to the Eurasia plate and currently the only one sitting on the Nubia Plate, thus sharing a geodynamic evolution with the Azores Triple Junction. It is therefore important to evaluate the effects of active tectonics on the evolution of Santa Maria, for example on its vertical movements. We present new stratigraphic, geomorphologic, structural and geochronological data from Santa Maria which shed further light on how a volcanic ocean island evolves in a tectonically active setting. Santa Maria island started with a first shield volcano (Old Volcanic Complex) that emerged ca. 6.0 Ma ago and was active until ca. 5.3 Ma. The short time span between the first and second shield volcanoes (ca. 0.3 Ma) and the preservation of only the western flank of this first shield volcano indicate an initial flank collapse at ca. 5 Ma. The collapse scar was covered by an eastwards dipping sedimentary complex (Intermediate Sedimentary Complex), with a likely tsunami deposit at the base. A second shield volcano (Young Volcanic Complex) rapidly grew on these sediments from 4.8 to 3.8 Ma, and the island subsided by more than 100 m. At 3.7 Ma, a second flank collapse occurred, as inferred from the missing summit and eastern flank. Volcanism then resumed (3.6 to 2.8 Ma), giving rise to Strombolian cones lying unconformably on the collapse scar and conformable parasitic cones on the unaffected flank. Submarine lavas occurring at up to 200 m altitude with a youngest age of 3.0 Ma indicate major uplift of the island since, at most, that time. Here we interpret uplift as the result of rift flank uplift on the southern shoulder of the nearby Terceira Rift in the last ca. 1.5 Ma.

中文翻译：

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亚速尔群岛三重交汇点背景下圣玛丽亚岛的演变

圣玛丽亚岛是亚速尔群岛最古老的岛屿，以前属于欧亚大陆板块，现在是唯一一个坐落在努比亚板块上，因此与亚速尔群岛三重交汇点共享地球动力学演化。因此，重要的是评估活动构造对圣玛丽亚演化的影响，例如对其垂直运动的影响。我们展示了来自圣玛丽亚的新地层、地貌、构造和地质年代学数据，这些数据进一步阐明了火山岛如何在构造活跃的环境中演化。圣玛丽亚岛始于大约出现的第一座盾状火山（旧火山群）。6.0 Ma 之前一直活跃到大约。5.3 马。第一个和第二个盾状火山之间的短时间跨度（大约 0. 3 Ma) 和仅保存这第一座盾状火山的西侧表明大约在 5 马。崩塌疤痕被东倾沉积复合体（Intermediate Sedimentary Complex）覆盖，底部可能有海啸沉积。从 4.8 到 3.8 Ma，第二座盾状火山（Young Volcanic Complex）在这些沉积物上迅速生长，岛屿下沉超过 100 m。根据缺失的顶峰和东翼推断，在 3.7 Ma 发生了第二次侧翼坍塌。火山活动然后恢复（3.6 到 2.8 Ma），导致 Strombolian 锥体不整合地躺在塌陷疤痕上，而在未受影响的侧翼出现整合的寄生锥体。海底熔岩出现在高达 200 m 的高度，最年轻的年龄为 3.0 Ma，表明该岛最多从那时起发生了重大隆升。在这里，我们将隆起解释为最后一个 ca. 附近特塞拉裂谷南肩裂谷侧翼隆起的结果。1.5 马。