On the Bay of Biscay continental shelf, there are several mid-shelf mud patches including La Grande Vasière to the north, the West Gironde Mud Patch (WGMP) off the Gironde estuary and the Basque Mud Patch close to the Spanish border. In general, these deposits are several meters thick and cover coarser substrate. Questions remain about their storage capability for fine particles and carbon. This work investigates the sedimentation of the WGMP in order to develop a first estimate of organic carbon (OC) burial. Interface sediment cores were collected at nine stations along two cross-shelf transects in October–November 2016. X-radiograph imaging and grain-size analyses were used to characterize sedimentary structures. ²¹⁰Pb_xs depth profiles were established to calculate sediment (SAR) and mass (MAR) accumulation rates. Sedimentary structures indicate episodic sandy inputs overlying older deposits at proximal sites, and relatively continuous sedimentation at seaward locations. On the outer-central portion of the northern transect, a maximum SAR (0.47 cm yr⁻¹) was observed, suggesting a depocenter. On the southern transect, excluding two stations where sedimentary inputs appear massive but sporadic, the SARs are lower (<0.3 cm yr⁻¹). Quantitative estimates of OC burial rates increase seaward with a maximum of 45 gC m⁻² yr⁻¹. To evaluate carbon loading independent of grain-size variability, OC values were normalized to surface area of sediments (SA). Interestingly, a qualitative comparison of OC burial efficiencies using the OC/SA ratio highlights three groups of sites (low, medium and relatively high OC burial efficiency) which are likely related both to different sedimentary environments and variable deposition conditions linked to local environmental conditions and depth. This work highlights the likely control of hydrodynamic intensity and sedimentary inputs on the amount of OC stored in the WGMP sediments.

在比斯开湾的大陆架湾上，有几个中层的泥地，包括北部的La GrandeVasière，吉伦特河口外的西吉伦特河泥地带（WGMP）和靠近西班牙边境的巴斯克泥地带。通常，这些沉积物厚几米，覆盖较粗糙的基材。关于它们对微粒和碳的储存能力仍然存在疑问。这项工作调查了WGMP的沉积，以便对有机碳（OC）埋葬进行初步估算。2016年10月至11月，在两个交叉架样线的9个站采集了界面沉积物岩心。X射线照相成像和粒度分析用于表征沉积物结构。²¹⁰磅_xs建立深度剖面以计算沉积物（SAR）和质量（MAR）累积速率。沉积结构表明，在近端位置上较老的沉积物上有偶发性的沙质输入，而在朝海位置上则是相对连续的沉积。在北样带的中部外部分，观察到最大比吸收率（0.47 cm yr ^-1），表明沉积中心。在南部样带上，不包括沉积物输入量大但零星的两个站点，SARs较低（<0.3 cm yr ^-1）。OC埋葬率的定量估计值向海增加，最大为45 gC m ^-2 yr ^-1。为了评估与颗粒大小无关的碳负荷，将OC值归一化为沉积物（SA）的表面积。有趣的是，使用OC / SA比对OC埋葬效率进行定性比较时，可以突出显示三组地点（低，中和相对较高的OC埋葬效率），它们可能与不同的沉积环境以及与当地环境条件相关的可变沉积条件有关。深度。这项工作强调了对水动力强度和沉积物输入量可能对WGMP沉积物中储存的OC量的控制。