The identification and distinction of fluvial from lacustrine deposits and the recognition of catchment changes are crucial for the reconstruction of climate changes in terrestrial environments. The investigated drill core succession shows a general evolution from red–brown claystones to white–grey marlstones and microcrystalline limestones, which all have previously been considered as relict deposits of an impact ejecta-dammed lake, falling within the mid-Miocene Climate Transition. However, recent mammal biostratigraphic dating suggests a likely pre-impact age. Indeed, no pebbles from impact ejecta have been detected; only local clasts of Mesozoic formations, in addition to rare Palaeozoic lydites from outside of the study area. Lithofacies analysis demonstrates only the absence of lacustrine criteria, except for one charophyte-bearing mudstone. Instead, the succession is characterized by less diagnostic floodplain fines with palaeosols, palustrine limestones with root voids and intercalated thin sandstone beds. Carbonate isotope signatures of the mottled marlstones, palustrine limestones and mud-supported conglomerates substantiate the interpretation of a fluvial setting. Low, invariant δ¹⁸O_carb reflects a short water residence time and highly variable δ¹³C_carb indicates a variable degree of pedogenesis. Carbonate ⁸⁷Sr/⁸⁶Sr ratios of the entire succession show a unidirectional trend from 0.7103 to 0.7112, indicating a change of the solute provenance from Triassic to Jurassic rocks, identical to the provenance trend from extraclasts. The increase in carbonate along the succession is therefore independent from climate changes but reflects a base-level rise from the level of the siliciclastic Upper Triassic to the carbonate-bearing Lower to Middle Jurassic bedrocks. This study demonstrates that, when information on sedimentary architecture is limited, a combination of facies criteria (i.e. presence or absence of specific sedimentary structures and diagnostic organisms), component provenance, and stable and radiogenic isotopes is required to unequivocally distinguish between lacustrine and fluvial sediments, and to disentangle regional geological effects in the catchment and climate influences.

中文翻译：

---

沉积学和碳酸盐同位素特征，以识别假定的撞击喷射物堰塞湖（德国中新世）中的河流过程和集水区变化

河流与湖泊沉积物的识别和区分以及流域变化的识别对于重建陆地环境中的气候变化至关重要。研究的钻芯序列显示了从红棕色粘土岩到白灰色泥灰岩和微晶石灰岩的一般演变，这些以前都被认为是撞击喷出物堰塞湖的残余沉积物，属于中中新世气候转变。然而，最近的哺乳动物生物地层测年表明一个可能的撞击前年龄。事实上，没有检测到来自撞击喷射物的卵石。除了来自研究区之外的罕见的古生代岩溶岩外，只有中生代地层的局部碎屑。岩相分析表明，除了一处含轮藻的泥岩外，没有湖相标准。相反，该系列的特征是具有古土壤的诊断性泛滥平原细粒较少，具有根部空隙的沼泽灰岩和夹层薄砂岩层。斑驳的泥灰岩、沼泽灰岩和泥土支撑的砾岩的碳酸盐同位素特征证实了对河流环境的解释。低、不变的 δ¹⁸ O _carb反映了较短的水停留时间，而高度可变的 δ ¹³ C _carb表明成土作用程度不同。碳酸盐⁸⁷ Sr/ ⁸⁶整个序列的Sr比值呈现0.7103～0.7112的单向趋势，表明溶质物源由三叠系向侏罗系变化，与外碎屑物源趋势一致。因此，沿序列碳酸盐岩的增加与气候变化无关，但反映了从硅质碎屑岩上三叠统到含碳酸盐岩的下侏罗统基岩的基准面上升。这项研究表明，当有关沉积结构的信息有限时，需要结合相标准（即特定沉积结构和诊断生物的存在与否）、成分来源以及稳定和放射性同位素来明确区分湖泊沉积物和河流沉积物,