Sedimentary Geology最新文献_第3页

Sedimentary processes of fine-grained sedimentary rocks in lacustrine basins: A case study of the Upper Cretaceous Qingshankou Formation, northern Songliao Basin, China 湖相盆地细粒沉积岩沉积过程——以松辽盆地北部上白垩统青山口组为例

IF 2.9 2区地球科学 Q1 GEOLOGY

Sedimentary Geology

Pub Date : 2025-10-25 DOI: 10.1016/j.sedgeo.2025.106987

NingLiang Sun , Jinyou Zhang , Jianhua Zhong , Jianbo Gao , Pengpeng Sheng , Zhiwei Chen , Zhifeng Cao , Pingshuai Wang

Fine-grained sedimentary rocks (FGSRs) in lacustrine basins are traditionally interpreted as low-energy suspension deposits. However, extensive shale oil exploration has revealed pronounced lithofacies heterogeneity within mudstone successions, necessitating a re-evaluation of their dynamic depositional processes. This study integrates data from eleven cored boreholes, along with petrographic and geochemical analyses, to characterize lithofacies variability, depositional processes, and environmental evolution of the Upper Cretaceous Qingshankou Formation FGSRs in the Songliao Basin. Sedimentological and geochemical proxies indicate that FGSR deposition occurred in brackish-saline waters with moderate stratification and persistent anoxia under warm-humid climatic conditions. A revised depositional framework identifies eight lithofacies and delineates four lacustrine depositional environments that were shaped by intermittent marine incursions: (i) sublittoral proximal deposits, consisting of interlaminated mudstones and siltstones associated with storm-induced tempestites and muddy hyperpycnal flows; (ii) sublittoral distal deposits, dominated by wave-enhanced sediment gravity flows with tripartite microstratigraphy recording turbulent-to-laminar flow transitions; (iii) semi-profundal deposits, comprising hybrid event beds and bottom-current deposits with rhythmically discontinuous silt laminae and mud ripples, the latter formed through bedload transport of clay aggregates under sustained current velocities; (iv) profundal deposits, including laminated varves, organic-rich suspension mudstones, and tuff layers. Their high organic carbon content and minimal bioturbation establish them as important targets for unconventional shale oil exploration. These findings challenge the conventional paradigm of deep-lacustrine quiescence, highlighting the pervasive influence of energetic depositional processes in shaping shale heterogeneity and organic matter preservation. The results have significant implications for the exploration and characterization of lacustrine shale reservoirs on a global scale.

湖盆细粒沉积岩（FGSRs）传统上被解释为低能悬浮沉积。然而，广泛的页岩油勘探揭示了泥岩层序中明显的岩相非均质性，需要对其动态沉积过程进行重新评价。本研究综合了松辽盆地上白垩统青山口组11个取心钻孔资料，结合岩石学和地球化学分析，对松辽盆地上白垩统青山口组的岩相变异性、沉积过程和环境演化进行了研究。沉积学和地球化学指标表明，FGSR沉积发生在温湿气候条件下的中等分层和持续缺氧的微咸海水中。经修订的沉积格架确定了8种岩相，并圈定了4种由间歇性海侵形成的湖泊沉积环境：(1)海下近端沉积，由层间泥岩和粉砂岩组成，与风暴引起的暴风雨和泥质超旋流有关；（ii）以波浪增强沉积物重力流为主的滨海下远端沉积物，其三段式微地层记录了湍流到层流的转变；（iii）半深层沉积，包括混合事件层和底流沉积，具有节律不连续的粉砂纹层和泥纹，后者是在持续水流速度下由粘土集料的层载搬运形成的；（iv）深层沉积，包括层状阀、富有机质悬浮泥岩和凝灰岩层。有机碳含量高，生物扰动小，是非常规页岩油勘探的重要靶区。这些发现挑战了深湖静止的传统范式，强调了高能沉积过程在形成页岩非均质性和有机质保存方面的普遍影响。研究结果对全球范围内湖相页岩储层的勘探和表征具有重要意义。

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引用次数: 0

Dedolomitization-driven karstification and speleogenesis in central Slovenia: Mineralogical and geochemical insights 斯洛文尼亚中部去白云石化驱动的岩溶作用和洞穴成因：矿物学和地球化学见解

IF 2.9 2区地球科学 Q1 GEOLOGY

Sedimentary Geology

Pub Date : 2025-10-21 DOI: 10.1016/j.sedgeo.2025.106986

Filip Šarc , Tomasz Powolny , Andrea Martín-Pérez , Adrijan Košir , Beata Gebus-Czupyt , Andrzej Tyc , Justyna Ciesielczuk , Christoph Spötl , Gabriella Koltai , Bojan Otoničar

This study examines the petrography and geochemistry of dolomite wall rock and associated dedolomite in the Mravljetovo brezno v Gošarjevih rupah cave system of central Slovenia and evaluates the influence of dedolomitization on speleogenesis and karstification. Three distinct dedolomitization-related facies were identified: (i) Type 1, featuring dolomite replaced and cemented by calcite; (ii) Type 2, characterized by bladed and cone-shaped calcite associated with clay minerals and iron oxides; and (iii) Type 3, a detrital, stratified deposit resulting from host rock weathering and allogenic sedimentation and diagenesis in phreatic conditions. Geochemical analyses reveal a progressive loss of Mg and Sr, enrichment in Ca, starting from the unaltered dolomite of the wall rocks up to all facies associated with dedolomitization. In addition, enrichment of Si, Al, Fe and other silicate-associated elements were observed in all dedolomite types. Stable isotope (δ¹³C, δ¹⁸O) data suggest organic carbon input and meteoric diagenesis as primary controlling factors. ΣREE+Y patterns, negative Ce anomalies (Ce/Ce* < 1) and the enrichment in some trace elements (e.g. Zr, Zn, Cu, Pb, Ba) indicate an oxidative environment with a strong detrital influence. Structural discontinuities played a crucial role in directing fluids and detrital material along fault zones and bedding planes which facilitated dedolomitization and subsequently cave formation. The findings show that dedolomitization not only altered the original dolostone fabric but also facilitated speleogenesis by enhancing rock heterogeneity and increasing its susceptibility to dissolution, while at the same time playing an important role in karstification and the further development of dolostone landscape.

本文研究了斯洛文尼亚中部Mravljetovo brezno v Gošarjevih rupah洞穴系统中白云岩围岩和伴生白云岩的岩石学和地球化学特征，并评价了脱白云化作用对洞穴形成和岩溶作用的影响。确定了3种不同的脱白云化相：(i) 1型，白云岩被方解石取代并胶结；第2类，其特点是与粘土矿物和氧化铁有关的叶状和锥形方解石；（iii）第3型，由寄主岩石风化和在潜水条件下的异源沉积和成岩作用形成的碎屑层状矿床。地球化学分析表明，从围岩未蚀变白云岩开始，直至脱白云化相关的所有相，镁、锶逐渐损失，Ca富集。此外，所有类型的泥白云岩均富集硅、铝、铁等硅酸盐伴生元素。稳定同位素（δ13C、δ18O）数据表明，有机碳输入和大气成岩作用是主要控制因素。ΣREE+Y模式、负Ce异常（Ce/Ce* < 1）和部分微量元素（如Zr、Zn、Cu、Pb、Ba）的富集表明其为氧化环境，受碎屑影响较大。构造不连续面在引导流体和碎屑物质沿断裂带和层理平面的过程中起着至关重要的作用，促进了脱白云石化和随后的溶洞形成。研究结果表明，脱白云石化不仅改变了原有的白云岩结构，而且通过增强岩石的非均质性和增加其对溶蚀的敏感性，促进了洞穴的形成，同时在岩溶作用和白云岩景观的进一步发展中起着重要作用。

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引用次数: 0

A comparison in hierarchies and architectures between submarine trunk versus tributary canyons and their evolution: A case study from northwestern South China Sea margin 海底干流峡谷与支流峡谷的等级结构比较及其演化——以南海西北海域为例

IF 2.9 2区地球科学 Q1 GEOLOGY

Sedimentary Geology

Pub Date : 2025-10-21 DOI: 10.1016/j.sedgeo.2025.106985

Dongwei Li , Chenglin Gong , Ronald J. Steel , Yijie Zhu

Submarine canyons are important conduits for transporting sediment across continental margins and their canyon heads contribute to further understanding the shelf-to-canyon sedimentary dynamics. Limited attention has been given to describe the internal depositional architectures and their variations from the tributary to trunk canyons in the canyon head regions. High-resolution 3-D seismic data tied to well logs, cores, and grain-size data from the Central Submarine Canyon head developed during late Miocene in Qiongdongnan Basin are utilized to investigate the variation of the hierarchical framework and depositional architectures between tributary and trunk canyons. The results show that canyon head tributaries contain one type of stratigraphic surfaces (i.e., fourth-order erosion surface) and four types of depositional elements (i.e., thalweg sandy debrites, axial high net-to-gross turbidites, off-axial low net-to-gross turbidites, and bank failures). The trunk canyon, in contrast, are characterized by a more complex hierarchical and depositional style, and are distinguished from tributary canyons by the occurrence of internal levees and the fifth-order erosion surface, composed of multiple seismically resolvable incisions. The evolution of the canyon head suggests that tributary canyons at the canyon head erode downstream and converge into the previously developed trunk canyon under the control of paleo-topography, forming a dendritic structure in plan-view. Results from this paper contributes to a better understanding on hierarchical framework and depositional architectures of the submarine canyon head.

海底峡谷是大陆边缘输沙的重要通道，其峡谷头有助于进一步认识陆架-峡谷的沉积动力学。对峡谷头区支流-干流峡谷内部沉积构型及其变化的研究较少。利用琼东南盆地晚中新世形成的中央海底峡谷头部的测井、岩心和粒度数据，结合高分辨率三维地震数据，研究了支流和干流峡谷之间的等级格架和沉积构型的变化。结果表明，峡谷头支流包含1种地层面（即4级侵蚀面）和4种沉积元素（即重质砂质碎屑、轴向高净比浊积、离轴低净比浊积和河岸断层）。干流峡谷则具有更为复杂的层次性和沉积风格，其与支流峡谷的区别在于其内堤和由多个地震可分辨切口组成的5级侵蚀面。峡谷头的演化表明，在古地形的控制下，峡谷头的支流峡谷向下游侵蚀，汇成先前发育的主干峡谷，在平面上形成树枝状结构。本文的研究结果有助于更好地理解海底峡谷头的等级格架和沉积构型。

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引用次数: 0

Sedimentary rates driven by laboratory lock-exchange turbidity currents flowing over gravel and vegetated beds 由实验室锁交换浊度流在砾石和植被层上流动所驱动的沉积速率

IF 2.9 2区地球科学 Q1 GEOLOGY

Sedimentary Geology

Pub Date : 2025-10-09 DOI: 10.1016/j.sedgeo.2025.106978

T. Serra , M. Soler , M. Mancini , L. Solari , J. Colomer

Turbidity currents are key agents in sediment transport and bed reshaping, influencing geological records, organic carbon fluxes and pollutant transport. While extensively studied over smooth beds, their interaction with rough beds, such as gravel or vegetated substrates, remains poorly understood. Existing studies suggest bed roughness slows flow and alters deposition, but a comprehensive understanding of how grain-size affects current dynamics and sedimentation patterns is lacking. In this study, we addressed key knowledge gaps on the influence of bed roughness and vegetation on turbidity current dynamics and sedimentation by conducting a comprehensive series of lock-exchange flume experiments. Six bed grain-sizes, multiple flow depths, and sediment concentrations were tested and compared with previous experiments on simulated and real vegetation. Results demonstrate that increasing bed roughness significantly reduces turbidity current velocity and enhances near-source sediment deposition. Greater deposits close to the source result in more non-uniform sediment distribution, with less deposition along the gravel bed. Conversely, smooth beds facilitate longer sediment transport and more uniform deposition. Flow regimes were observed to shift from inertial to drag-dominated as a function of bed configuration, with vegetated and coarse-grained beds inducing comparable hydraulic resistance. Sediment deposition patterns were closely linked to bed roughness and influenced clogging processes via unimpeded static percolation. Overall, the findings reveal a strong feedback between substrate morphology and turbidity current behaviour, with important implications for turbidite formation, sedimentary structure development, and hyporheic exchange dynamics.

浊流是泥沙运移和河床重塑的关键因素，影响地质记录、有机碳通量和污染物运移。虽然对光滑地层进行了广泛的研究，但它们与粗糙地层（如砾石或植被基质）的相互作用仍然知之甚少。现有的研究表明，河床粗糙度减缓了水流并改变了沉积，但缺乏对粒度如何影响水流动力学和沉积模式的全面理解。在这项研究中，我们通过进行一系列全面的锁交换水槽实验，解决了河床粗糙度和植被对浊度流动力学和沉积影响的关键知识空白。在模拟植被和真实植被上测试了6种河床粒度、多种水流深度和沉积物浓度，并进行了比较。结果表明，增加河床粗糙度可显著降低浊流流速，促进近源泥沙沉积。靠近源的沉积物越多，沉积物分布就越不均匀，沿砾石层的沉积物就越少。相反，光滑的河床有利于沉积物输送更长的时间和更均匀的沉积。研究人员观察到，随着河床结构的变化，流动状态从惯性转向以阻力为主，植被覆盖的河床和粗粒度河床的水力阻力相当。沉积物沉积模式与河床粗糙度密切相关，并通过无阻碍的静态渗流影响堵塞过程。总的来说，这些发现揭示了底物形态和浊流行为之间的强烈反馈，对浊积岩的形成、沉积结构的发育和潜流交换动力学具有重要意义。

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引用次数: 0

Architecture and evolution of early Pleistocene shelf margin clinoforms, northwestern South China Sea: Implications for high-frequency sequence architecture 南海西北部早更新世陆架边缘陆形的构造与演化：对高频层序结构的启示

IF 2.9 2区地球科学 Q1 GEOLOGY

Sedimentary Geology

Pub Date : 2025-10-09 DOI: 10.1016/j.sedgeo.2025.106984

Yueyao Chen , Jiawang Ge , Xiaoming Zhao , Ronald Steel , Kun Qi , Xiaolong Tang

The controls on cross-shelf deltaic architecture variability and high-frequency clinoform development along continental margins remain inadequately explored. Recently acquired high-resolution seismic data from the passive continental margin in the northwestern South China Sea offer an opportunity to investigate the intra-sequence architecture and shelf-edge trajectories of the early Pleistocene (2.6 to 1.8 Ma) succession in detail. Five high-frequency sequences, with an average duration of ∼160 kyr in duration (4th-order sequences), exhibit distinct intra-sequence architectures and are related to four shelf-edge trajectory types: descending, slightly ascending, steeply ascending, and backstepping. The observed correlation between shelf-edge trajectories and intra-sequence architectures under high-frequency sea-level fluctuations reflects the dynamic interplay between accommodation and sediment supply, underscoring their potential as predictive tools in depositional process analysis.

The stratal variability of early Pleistocene shelf-margin clinoforms documented in this study is controlled by a combination of factors, including sea-level fluctuations, climate, sediment supply, and tectonics. The reduced dominance of falling-stage systems tracts during the early Pleistocene compared to the late Pleistocene is attributed to the lower amplitude and more symmetrical nature of sea-level changes, which restricted the dominance of falling-stage systems tracts. The well-preserved transgressive and regressive units reflect sufficient sediment supply and paced accommodation creation. Our results emphasize that the local variations in high-frequency sequence architecture were shaped by multiple factors beyond sea-level changes in the early Pleistocene shelf-margin. Local factors such as tectonism and sediment supply can complicate the correlation of seismic sequences, even across relatively short distances.

陆架间三角洲构造变异性和沿大陆边缘高频斜形发育的控制因素仍未得到充分探讨。最近在南海西北部被动大陆边缘获得的高分辨率地震资料为详细研究早更新世（2.6 ~ 1.8 Ma）序列的层序内结构和陆架边缘轨迹提供了机会。5个平均持续时间为~ 160 kyr的高频序列（4阶序列）表现出不同的序列内结构，并与4种陆架边缘轨迹类型相关：下降、轻微上升、急剧上升和后退。观察到的高频率海平面波动下陆架边缘轨迹与层序内结构之间的相关性反映了调节和沉积物供应之间的动态相互作用，强调了它们作为沉积过程分析预测工具的潜力。本研究记录的早更新世陆架边缘斜形地层变异性受海平面波动、气候、沉积物供应和构造等因素的综合控制。与晚更新世相比，早更新世下降阶段体系域的优势程度有所降低，这是由于海平面变化幅度较低且更具对称性，限制了下降阶段体系域的优势程度。保存完好的海侵和退退单元反映了充足的沉积物供应和有节奏的调节作用。我们的研究结果强调，高频层序结构的局部变化是由早更新世陆架边缘海平面变化以外的多种因素造成的。局部因素，如构造作用和沉积物供应，即使在相对较短的距离内，也会使地震序列的相关性复杂化。

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引用次数: 0

Detrital zircon U–Pb ages and provenance of Permian sandstones from Sado Island, central Japan: Implications for Rodinia-derived sources in the eastern Central Asian Orogenic Belt 日本中部佐渡岛二叠系砂岩碎屑锆石U-Pb年龄及物源特征：对中亚造山带东部rodinia源的启示

IF 2.9 2区地球科学 Q1 GEOLOGY

Sedimentary Geology

Pub Date : 2025-10-08 DOI: 10.1016/j.sedgeo.2025.106983

Keisuke Suzuki , Toshiyuki Kurihara , Hirotaka Ishida , Toshiro Takahashi , Hayato Ueda

To better understand the sedimentation, tectonics, and paleogeographic evolution of Northeast Asia, we present new integrated data including sandstone petrography, whole-rock geochemistry, and detrital zircon U–Pb ages for Permian strata of Sado Island in the Sea of Japan. The sandstones are rich in quartz and feldspar and are classified as feldspathic arenite and wacke. They exhibit high SiO₂, La, Th, and Zr contents, and light rare earth element enrichment with flat heavy rare earth patterns, indicating an island arc provenance with granitic basement exposure. Trace element enrichments (e.g., V, Cr, and Ni) suggest the partial presence of exposed mafic igneous rocks on the arc surface. Detrital zircon U–Pb ages show middle–late Permian (270–256 Ma) peaks, along with late Mesoproterozoic to middle Neoproterozoic (1022–762 Ma) and middle Cambrian to Early Devonian (507–403 Ma) populations. The Mesoproterozoic–Neoproterozoic zircons originated from the Songliao–Xilinhot and Jiamusi–Khanka blocks in the eastern Central Asian Orogenic Belt, associated with peripheral orogenies of the supercontinent Rodinia. The Cambrian zircons (540–510 Ma) with low Th/U ratios (<0.44) likely reflect detritus contributions from granite and amphibolite- to granulite-facies metamorphic rocks associated with the Mashan Complex of the Jiamusi–Khanka Block. Double-sided subduction zones between the North China Craton and the Songliao–Xilinhot and Jiamusi–Khanka blocks may have provided a tectonic linkage between Sado Island, Rodinia-derived source regions, and complex arc–trench systems at the junction of the Paleo-Asian–Mudanjiang and Paleo-Pacific oceans during the middle–late Permian.

为了更好地理解东北亚地区的沉积、构造和古地理演化，我们对日本海佐渡岛二叠系地层进行了砂岩岩石学、全岩地球化学和碎屑锆石U-Pb年龄的综合研究。砂岩富含石英和长石，可分为长石砂质砂岩和长石砂质砂岩。它们具有较高的sio2、La、Th、Zr含量，轻稀土元素富集，重稀土元素呈扁平模式，表明物源为岛弧型花岗岩基底出露。微量元素的富集（如V、Cr和Ni）表明弧表面部分存在暴露的基性火成岩。碎屑锆石U-Pb年龄表现为中晚二叠世（270 ~ 256 Ma）峰值，中元古代晚期至新元古代中期（1022 ~ 762 Ma）和中寒武统至早泥盆世（507 ~ 403 Ma）居群。中元古代—新元古代锆石产于中亚造山带东部松辽—锡林浩特和佳木斯—汉卡地块，与罗丁尼亚超大陆的外围造山活动有关。寒武系锆石（540 ~ 510 Ma） Th/U比值较低（<0.44），可能反映了与嘉木斯—汉卡地块马山杂岩有关的花岗岩和角闪岩—麻粒岩相变质岩的碎屑贡献。华北克拉通与松辽—锡林浩特和佳木斯—汉卡地块之间的双面俯冲带可能在二叠纪中晚期为佐渡岛、罗迪尼亚源区以及古亚洲—牡丹江和古太平洋交界处的复杂弧沟体系之间提供了构造联系。

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引用次数: 0

Multi-episodic bauxitization in a karstic and rifted setting (Early Cretaceous, South-western Iberian Basin, Spain): An interdisciplinary approach 岩溶和裂谷环境中的多期铝土矿化（早白垩世，西班牙伊比利亚盆地西南部）：一个跨学科的方法

IF 2.9 2区地球科学 Q1 GEOLOGY

Sedimentary Geology

Pub Date : 2025-10-06 DOI: 10.1016/j.sedgeo.2025.106981

Elisa Laita , Alejandro Lorenzo , Raúl De La Horra , María Belén Muñoz-García , Alfonso Yuste , Blanca Bauluz , Marian Fregenal-Martínez

Bauxitic deposits serve as valuable sedimentary archives, offering insights into paleoclimatic, paleogeographic, and geodynamic processes over time. A multidisciplinary analysis of bauxitic deposits in the Cuenca Domain (Iberian Ranges, central Spain) aims to reconstruct their genesis in the framework of the geological evolution of this region during the Late Jurassic-Early Cretaceous rift episode. The bauxitic deposits preserve paleosol profiles that show multi-episodic processes of sedimentation, reworking, erosion, pedogenesis, and bauxitization, reflecting a landscape's dynamics that was strongly influenced by episodic tectonic activity. The presence of book-type kaolinite aggregates, ferruginous pisoids and ooids, and soil horizons provide evidence of in situ bauxitization. On the other hand, the presence of fractured pisoids and ooids, brecciated textures, and bauxitic C horizons also points to some degree of reworking. Authigenic boehmite suggests optimal conditions for bauxitization, whereas ferruginous crusts and peds at the top of the deposits point to a later ferruginization phase. A subsequent kaolinitization episode, probably driven by the infiltration of silica-rich fluids, is also recorded. By integrating stratigraphic, sedimentological, and mineralogical data, a succession of genetic stages in bauxite development has been identified, shaped by the tectonic evolution of the area. The proposed stratigraphic and pedogenetic model enhances the regional significance of the findings and enables a refined chronology of its tectonic evolution. The results highlight the potential of bauxitic materials, not only as paleoclimatic indicators but also as robust tools for reconstructing paleogeographic and tectonic conditions in complex settings where the sedimentary record is apparently homogeneous and extremely incomplete.

铝矾土矿床作为宝贵的沉积档案，提供了对古气候、古地理和地球动力学过程的见解。对西班牙中部伊比利亚山脉昆卡地区的铝土矿床进行了多学科分析，目的是在该地区晚侏罗世-早白垩世裂谷期地质演化的框架内重建其成因。铝土矿保存的古土壤剖面显示了沉积、改造、侵蚀、成土和铝土矿化的多期过程，反映了受期次构造活动强烈影响的景观动态。书型高岭石集合体、含铁的类铁和类铁以及土壤层的存在提供了原位铝矾土化的证据。另一方面，断裂的类球状体和类球状体、角化结构和铝土矿C层的存在也表明了某种程度的改造。自生薄水铝石表明铝土化的最佳条件，而矿床顶部的含铁结壳和沉积物则表明较晚的铁化阶段。随后的高岭土化事件，可能是由富硅流体的渗透驱动的，也有记录。通过综合地层学、沉积学和矿物学资料，确定了铝土矿发育的一系列成因阶段，这些阶段是由该地区的构造演化形成的。提出的地层和成土模式增强了这些发现的区域意义，并使构造演化的年代学更加精细。研究结果表明，铝矾土材料不仅可以作为古气候指标，而且可以作为在沉积记录明显均匀且极不完整的复杂环境中重建古地理和构造条件的有力工具。

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引用次数: 0

Comparative grain size analysis of fine-grained sediments: A case study of the Opalinus Clay, northern Switzerland 细粒沉积物的粒度比较分析：以瑞士北部蛋白石粘土为例

IF 2.9 2区地球科学 Q1 GEOLOGY

Sedimentary Geology

Pub Date : 2025-10-02 DOI: 10.1016/j.sedgeo.2025.106982

Géraldine Nicole Zimmerli , Alicia Fantasia , Stephan Wohlwend , Gaudenz Deplazes , Anneleen Foubert

Grain size variability in fine-grained sediments is a critical factor influencing the physical, geomechanical, geochemical, and hydrological properties of sedimentary rocks. Even small changes in grain size can significantly alter rock behavior. Despite many decades of research on fine-grained sediments in different depositional settings, studies focusing on the comparative and quantitative calibrated analysis of grain size variations in fine-grained Mesozoic sediments are scarce. This study provides the first integrative, quantitative, comparative, and comprehensive analysis of grain size variability in the detrital fraction of the Opalinus Clay from northern Switzerland (Stadel-2 core), which serves as the designated host rock for radioactive waste disposal. The analyses include 2D image analysis, X-ray micro-computed tomography, laser particle size analysis, and sieving/decantation analysis, alongside mineralogical (X-ray diffraction, XRD) and geochemical (X-ray fluorescence, XRF) analyses. Strong correlations between grain size and elemental ratios (Si/Al, Ti/Al, Zr/Al, Zr/Rb) suggest that these ratios can serve as effective proxies for grain size variations in the Opalinus Clay, primarily controlled by the presence of quartz and phyllosilicates. Results evidence the dominance of silt-sized particles in the Opalinus Clay. Distinct trends of grain size coarsening and fining are observed based on XRF-derived grain size proxies, providing the base for further studies on sediment transport processes, including sediment provenance, flow strength, and current dynamics associated with the Opalinus Clay. Results highlight the importance of calibrating grain size variations in fine-grained sediments before their application in the understanding of rock properties and sedimentary processes.

细粒沉积物的粒度变异性是影响沉积岩物理、地质力学、地球化学和水文性质的关键因素。即使颗粒大小的微小变化也能显著改变岩石的行为。尽管对不同沉积环境下的细粒沉积物进行了数十年的研究，但对中生代细粒沉积物粒度变化进行比较和定量校准分析的研究很少。本研究首次对瑞士北部Opalinus Clay碎屑组分（stadel2岩心）的粒度变化进行了综合、定量、比较和综合分析，该岩心是放射性废物处置的指定寄主岩石。分析包括二维图像分析，x射线微计算机断层扫描，激光粒度分析，筛分/脱析分析，以及矿物学（x射线衍射，XRD）和地球化学（x射线荧光，XRF）分析。晶粒尺寸与元素比值（Si/Al, Ti/Al, Zr/Al, Zr/Rb）之间的强相关性表明，这些比值可以作为欧白石粘土晶粒尺寸变化的有效指标，主要由石英和层状硅酸盐的存在控制。结果表明，在蛋白石粘土中，粉粒大小的颗粒占主导地位。基于xrf衍生的粒度指标，观察到明显的粒度粗化和细化趋势，为进一步研究蛋白石粘土的沉积物输运过程提供了基础，包括沉积物来源、流动强度和与之相关的水流动力学。结果强调了在细粒沉积物中校准粒度变化的重要性，然后将其应用于理解岩石性质和沉积过程。

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引用次数: 0

Sequence stratigraphy of wave-dominated and wave-influenced shoreface deposits: Systems tracts, stratigraphic surfaces and facies contacts 波浪主导和波浪影响的滨面矿床层序地层学：体系域、地层面和相接触

IF 2.9 2区地球科学 Q1 GEOLOGY

Sedimentary Geology

Pub Date : 2025-09-19 DOI: 10.1016/j.sedgeo.2025.106980

Massimo Zecchin , Octavian Catuneanu , Mauro Caffau

Shoreface deposits are usually associated with high-energy sedimentary structures, as well as with erosional surfaces produced by waves and currents that may have sequence stratigraphic or sedimentological significance. Typical sequence stratigraphic surfaces associated with shoreface deposits are the ravinement surface (RS), the maximum flooding surface (MFS), the basal surface of forced regression (BSFR), the regressive surface of marine erosion (RSME), the subaerial unconformity (SU) and the correlative conformity (CC). However, some of these surfaces, such as the MFS, the BSFR and the CC can be cryptic and difficult to pinpoint in outcrops and cores. Facies contacts in the shoreface are represented by the local flooding surface (LFS), the downlap surface (DLS), the surf diastem (SD) and bedset boundaries (BB), which are usually well recognizable. All downstream-controlled systems tracts may form in shoreface deposits, including the lowstand systems tract (LST), transgressive systems tract (TST), highstand systems tract (HST) and falling-stage systems tract (FSST). Among these systems tracts, TSTs and HSTs are most commonly recognized. A challenge in these settings is the distinction between HSTs, FSSTs and LSTs, due to the more subtle physical expression of the BSFR and the CC in fully shoreface successions. Sequence stratigraphic surfaces and facies contacts can be identified on the basis of several criteria, including sedimentological, ichnological, diagenetic, mineralogic, geophysical, and micropaleontological. Due to their easy recognition with all kinds of data, RSs are commonly chosen as boundaries of stratigraphic sequences composed of shoreface or mixed shoreface-shelf deposits, commonly referred to as transgressive-regressive (T-R) sequences.

滨面沉积通常与高能沉积构造以及可能具有层序地层学或沉积学意义的波浪和洋流所产生的侵蚀面有关。与滨面沉积相关的典型层序地层面有：冲蚀面（RS）、最大洪泛面（MFS）、强迫退退底面（BSFR）、海蚀退退面（RSME）、陆上不整合面（SU）和相关整合面（CC）。然而，其中一些表面，如MFS、BSFR和CC可能是神秘的，难以在露头和岩心中精确定位。滨面相接触由局部泛洪面（LFS）、下覆面（DLS）、逆冲面（SD）和层状边界（BB）代表，通常很容易识别。滨面沉积可形成各种下游控制体系域，包括低水位体系域（LST）、海侵体系域（TST）、高水位体系域（HST）和降级体系域（FSST）。在这些系统域中，TSTs和HSTs是最常见的。在这些环境中，由于BSFR和CC在全岸面序列中的物理表现更为微妙，因此区分hst、fsst和lst是一个挑战。层序地层面和相接触可根据沉积学、工艺学、成岩学、矿物学、地球物理和微古生物学等几种标准进行识别。由于其易于被各种资料识别，因此通常选择RSs作为由滨面或混合滨陆架沉积组成的层序的边界，通常称为海侵-退（T-R）层序。

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引用次数: 0

Principal component analysis reveals the relationship between carbonate facies, geochemical properties, and diagenetic overprint 主成分分析揭示了碳酸盐岩相、地球化学性质与成岩叠印之间的关系

IF 2.9 2区地球科学 Q1 GEOLOGY

Sedimentary Geology

Pub Date : 2025-09-19 DOI: 10.1016/j.sedgeo.2025.106979

Arman Jafarian , Antun Husinec , Rute Coimbra , Adrian Immenhauser , Umid Kakemem , Clemens V. Ullmann , Meng Wang , Abdus Saboor , Chengshan Wang

Marine carbonate archives in transitional coastal-to-basin settings are susceptible to syn- and post-depositional alteration, a feature that complicates the interpretation of primary environmental signals encoded in the sedimentary archive at the time of deposition. This study utilises Principal Component Analysis (PCA) to elucidate the intricate relationships between facies types, environmental controls, and the sediments' respective diagenetic susceptibilities to geochemical resetting within lower Aptian carbonates of the Kazhdumi Intrashelf Basin (Zagros Basin, Iran). The focus is on proximal mid-ramp to intrashelf-basin carbonates. Integrating facies analysis, petrography, geochemistry, and PCA, the following outcomes result: (i) Proximal facies exhibit higher Mn/Ca and lower Sr/Ca ratios linked to enhanced fluid-rock interactions and terrigenous input. Marine δ¹³C values and elevated Sr/Ca ratios are more pronounced in distal facies. (ii) Bulk isotope values from distal carbonates are characterised by enriched δ¹³C and depleted δ¹⁸O values. This suggests increased marine productivity in cooler waters and intermittently anoxic-suboxic conditions. (iii) In shallower, warmer, and well‑oxygenated proximal mid-ramp waters, reduced organic carbon burial, isotopically light carbon from terrestrial sources and the oxidation of organic matter result in lowered δ¹³C and higher δ¹⁸O values. The study demonstrates that despite complex diagenetic overprint, marine proxy signals remain discernible. Supported by microfacies data, PCA reveals a multi-faceted system that drives geochemical variability within a facies/bathymetric context. This outcome emphasises the critical importance of detailed facies analysis and geochemical profiling in reconstructing palaeoenvironmental conditions.

在过渡海岸-盆地环境下的海相碳酸盐档案容易受到同沉积蚀变和沉积后蚀变的影响，这一特征使沉积档案中编码的原始环境信号的解释变得复杂。本研究利用主成分分析（PCA）来阐明Kazhdumi陆架盆地（Zagros盆地）下Aptian碳酸盐岩中相类型、环境控制和沉积物各自对地球化学重置的成岩敏感性之间的复杂关系。重点是近中斜坡到陆架内盆地的碳酸盐岩。综合相分析、岩石学、地球化学和主成分分析，得出以下结果：(i)近端相表现出较高的Mn/Ca和较低的Sr/Ca比率，这与增强的流体-岩石相互作用和陆源输入有关。海相δ13C值和Sr/Ca比值的升高在远端相中更为明显。（ii）远端碳酸盐岩体同位素值以δ13C富集和δ18O亏缺为特征。这表明，在较冷的水域和间歇性缺氧-缺氧条件下，海洋生产力会增加。（iii）在较浅、较暖、氧合良好的中斜坡近端水体中，有机碳埋藏减少、陆源轻碳同位素化和有机质氧化导致δ13C值降低，δ18O值升高。研究表明，尽管存在复杂的成岩叠印，但海洋代理信号仍然可识别。在微相数据的支持下，PCA揭示了一个多方面的系统，该系统在相/水深背景下驱动地球化学变化。这一结果强调了详细的相分析和地球化学剖面在重建古环境条件中的重要性。

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引用次数: 0