Stratigraphic and Multi Scanner Core Logging (MSCL) data plus supplementary luminescence dating material obtained from the scientific drilling QDR-RE-IfG and its drill site in the Aare Valley, Bern CH

The Quaternary Drilling at the Rehhag under the supervision of members of the Institut für Geologie (QDR-RE-IfG) was interested in the unconsolidated sediment infill of a bedrock trough in the Northern Alpine Foreland (NAF). Such bedrock troughs, now hidden beneath their sediment infill and/or in lakes, occur in formerly and currently glaciated areas, and are linked to increased glacial erosion. The base of these bedrock troughs is located beneath today's base level, which puts them beyond fluvial erosion, and this is why they are referred to as over-deepenings. Such overdeepenings can be found in the vicinity of the Alps which includes the NAF. After the formation or re-occupation of such overdeepenings by glacier ice these troughs provide accommodation space for the deposition of sediments. Hence, overdeepenings are likely to preserve sediments through glacial-interglacial cycles. As erosive agents, glaciers re-shape landscapes, and excavate and re-use sediments of previous glaciations which makes the preservation of intact sedimentary sequences through multiple glacial cycles unlikely. These repeated cut-and-fill cycles limit the Quaternary sedimentary record and make the investigation of the number and chronology of Quaternary glacial-interglacial cycles difficult. Overdeepenings, however, can preserve fractionated and probably intact sedimentary sequences throughout multiple glaciations. Hence, accessing the sediment infill of overdeepened bedrock troughs through core drillings provides insight into phases of the Quaternary at locations where formerly little information was available. To gain new insight into the Mid- to Late-Pleistocene sedimentary record in the Bern area (Switzerland) the drilling QDR-RE-IfG was conducted in Bern-Bümpliz, where a minor branch of the Aare Valley overdeepening is located in which Quaternary sediments at least 150 ka in age were expected. In Bern-Bümpliz, at the Rehhag, the uppermost 30 m of the sedimentary succession are accessible in an abandoned clay pit. The drilling reached 211.5 m driller's depth, recovering 208.5 m of unconsolidated sediment and, below a sharp contact, 3 m of Miocene Molasse bedrock. The recovery of intact core from unconsolidated sediment is challenging. Nevertheless, 92.3% of the core material was recovered in 1 m-long plastic liners in pristine condition. As the drilling reached the bedrock it is the first scientific drilling that recovered the full sedimentary suite in a part of the Aare Valley overdeepening. Within the sedimentary succession two sequences (A = lower, B = upper) were identified. Each of the sequences is initiated by the deposition of glacial till that is overlain by lacustrine or glacio-lacustrine sediments. First luminescence ages indicate a depositional age between 250 and 340 ka for sequence B. The drill core was transported from the drill site to the Institute of Geological Sciences, University of Bern, where it was analyzed and sampled. The first step in the analysis was scanning the whole core contained in the liners on a Multi Sensor Core Logger (MSCL; Geotek Ltd.) which provided measurements of the core (γ-)density, p-wave velocity and magnetic susceptibility. The liners were then opened under light sensitive conditions, the cores split in half to allow their macroscopic description, and one half was sealed from light and other alterating influences. After the description, the core was documented with a digital line scanner on the MSCL. After the documentation, a vane meter was used to determine the shear strength of the material and samples for pollen analysis, analysis of the carbon content, provenance analysis, and the measurement of cosmogenic nuclides 10Be and 26Al were extracted. This report provides limited information about the drilling operation, describes the available datasets form scanning and sample analysis, and the results of the first data processing as well as the tools used in the data analysis.

在雷哈格（Rehhag）开展的由地质研究所（Institut für Geologie）成员主持的第四纪钻探项目（QDR-RE-IfG），旨在探究阿尔卑斯北部前陆（Northern Alpine Foreland，NAF）内一处基岩槽谷的松散沉积物充填物。这类基岩槽谷如今被沉积物掩埋或隐伏于湖泊之下，分布于历史及现代冰川作用区，与增强的冰川侵蚀作用密切相关。其谷底位于现代基准面之下，不受河流侵蚀作用影响，因此被称为超深槽（over-deepenings）。这类超深槽广泛分布于阿尔卑斯山周边区域，包括阿尔卑斯北部前陆。当冰川冰形成或再次占据超深槽后，槽谷便为沉积物沉积提供了可容空间，因此超深槽有望在冰期-间冰期旋回中保存沉积物记录。冰川作为侵蚀营力会重塑地表景观，挖掘并再利用此前冰期形成的沉积物，这使得完整的沉积序列难以在多次冰期旋回中得以保存。这类反复的侵蚀-充填循环限制了第四纪沉积记录的完整性，也使得第四纪冰期-间冰期旋回的期次与年代学研究颇具挑战。但超深槽却可在多次冰期过程中保存分异且近乎完整的沉积序列。因此，通过岩心钻探获取超深基岩槽谷的沉积物充填物，可为此前信息匮乏区域的第四纪演化阶段研究提供新的视角。为深入解析瑞士伯尔尼地区中更新世晚期至晚更新世的沉积记录，研究团队在伯尔尼-宾普利茨（Bern-Bümpliz）开展了QDR-RE-IfG钻探项目。该区域坐落着阿勒河谷超深槽的一条小型分支，预期可获取至少15万年（ka）年龄的第四纪沉积物。在宾普利茨的雷哈格区域，一处废弃黏土坑可直接出露沉积序列顶部30米的地层。本次钻探的钻进深度达211.5米，共获取208.5米的松散沉积物岩心，在清晰接触界面之下还获取了3米的中新世磨拉石（Miocene Molasse）基岩岩心。从松散沉积物中获取完整岩心颇具挑战，但最终92.3%的岩心以1米长的塑料岩心管保存，且处于原始完好状态。本次钻探穿透松散沉积层抵达基岩，是首个在阿勒河谷超深槽区域完整获取沉积序列的科学钻探项目。研究人员在该沉积序列中识别出两套地层单元（A为下部地层，B为上部地层）。每套地层均以冰碛物沉积为底，之上覆盖湖相或冰湖相沉积物。初步释光测年结果显示，上部地层B的沉积年龄介于25万至34万年之间。钻探岩心从现场被运送至伯尔尼大学地质科学研究所，开展后续分析与取样工作。分析工作的第一步是使用多传感器岩心扫描记录仪（Multi Sensor Core Logger，MSCL；Geotek Ltd.）对封装在岩心管内的完整岩心进行扫描，获取岩心的γ密度、纵波速度与磁化率数据。随后在避光条件下打开岩心管，将岩心剖为两半以开展宏观描述，并将其中一半岩心密封以隔绝光照及其他变质影响。宏观描述完成后，使用MSCL配套的数字线扫描记录仪对岩心进行数字化记录。数字化记录完成后，使用叶片剪力仪测定沉积物的抗剪强度，并采集了用于孢粉分析、碳含量分析、物源分析以及宇宙成因核素10Be和26Al测试的样品。本报告仅简要介绍本次钻探作业概况，梳理扫描与样品分析获取的可用数据集，展示首批数据处理结果及数据分析所用工具。