We acquired high-resolution reflection seismic data using a broadband digital-based landstreamer system to characterize a depression related to the Mesoproterozoic (Jothnian) Satakunta sandstone basin in the Köyliö study area, southwest Finland. This ca. 800-m-wide depression is infilled with up to 100-m-thick (late) Quaternary interlobate glaciofluvial complex sediments. The seismic images clearly reveal details of the glaciofluvial complex, sandstone depression topography, and brittle structures related to the formation of the sandstone basin by oblique transtension. Additionally, we identified the setting of a diabase laccolith within the sandstone and the geometry and position of the steep sandstone contact. The esker core does not follow the sandstone-Svecofennian basement rock contact or lean to it. The esker core is at a depth of 50–60 m on the flank of the depression. The seismic data image the esker core and other architectural elements of the esker. We highlight the potential of the digital-based landstreamer in the research of complex Quaternary sediments in major bedrock depressions including the characterization of the underlying bedrock properties. We also discuss the possible tunnel valley origin of the sandstone depression.

中文翻译：

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芬兰西南部 Köyliö 萨塔昆塔砂岩区晚第四纪冰川河流复合体的地球物理特征和冰川地层学

我们使用基于宽带数字的陆地流系统获取高分辨率反射地震数据，以描述与芬兰西南部 Köyliö 研究区的中元古代（约特尼纪）Satakunta 砂岩盆地相关的凹陷。这个约。800 米宽的凹陷被厚达 100 米（晚期）的第四纪间叶冰河复合沉积物填充。地震图像清楚地揭示了与斜向张紧形成砂岩盆地有关的冰川河流杂岩、砂岩凹陷地形和脆性构造的细节。此外，我们还确定了砂岩中辉绿岩岩的设置以及陡峭砂岩接触的几何形状和位置。esker 岩心不跟随砂岩-Svecofennian 基底岩石接触或倾斜于它。esker 岩心位于凹陷侧面 50-60 m 的深度。地震数据对 esker 核心和 esker 的其他架构元素进行成像。我们强调了基于数字的陆流器在主要基岩凹陷中复杂第四纪沉积物研究中的潜力，包括下伏基岩特性的表征。我们还讨论了砂岩凹陷可能的隧道谷起源。