Surface textures of quartz and ilmenite grains provide an insight in assessing current mechanical, chemical and mechanical-chemical processes in dune and beach sands of the Gulf of Mexico Coast (GMC) Mexico. The GMC area produces hybrid sands enriched in monocrystalline quartz and ilmenite-free grains. Quartz grains are observed in all dunes and beach localities of the central GMC close to the Trans-Mexican Volcanic Belt characterized by large conchoidal fractures (>100 μm), angular to subangular outlines, arcuate steps, high relief, and sharp edges associated with fluvial transport. Aeolian quartz features like meandering ridges, upturned plates, bulbous edges and adhering particles on quartz are only present in some GMC sites, whereas marine surface textures like straight and curved grooves are sparse. Chemical surface textures on quartz and ilmenite are a consequence of silica saturated low-energy subaqueous conditions and subaerial exposure, diagenesis and intermediate weathering processes in the dunes and beach sands. Ilmenite grains are common in all studied localities of the GMC, characterized by large conchoidal fractures (>100 μm), angular to subangular outlines, flat cleavage surfaces, arcuate steps and high relief. In some ilmenite grains, upturned plates, meandering ridges, bulbous edges and abrasion fatigue characterize aeolian surface features. Straight and curved grooves only characterize marine surface textures. To assess the prevailing transport mechanisms along the GMC, quartz and ilmenite grains from dunes and beach sands were selected based on surface texture observations. Our findings suggest that quartz and ilmenite grains are primarily transported and deposited along the coast by riverine input, a second-cycle of aeolian transport onshore, and recycling by marine longshore currents and waves.

石英和钛铁矿颗粒的表面纹理为评估墨西哥墨西哥湾沿岸（GMC）沙丘和海滩沙子中的当前机械，化学和机械化学过程提供了见识。GMC地区生产的混合砂富含单晶石英和不含钛铁矿的颗粒。在中墨西哥湾中部靠近跨墨西哥火山带的所有沙丘和海滩地区都观察到了石英颗粒，其特征是大的贝壳状裂缝（> 100μm），角形到亚角形轮廓，弓形台阶，高浮雕以及与河流相关的锋利边缘运输。风蚀性石英特征如曲折的脊，上倾的板块，球根状的边缘和石英上的附着颗粒仅出现在某些GMC地点，而海洋表面纹理（如直形和弯曲的凹槽）则很少。石英和钛铁矿上的化学表面纹理是二氧化硅饱和的低能水下条件以及沙丘和海滩沙中地下暴露，成岩作用和中间风化过程的结果。钛铁矿晶粒在GMC的所有研究区域中都很常见，其特征是大的贝壳状裂缝（> 100μm），角形到亚角形轮廓，平坦的乳沟表面，弧形台阶和高浮雕。在某些钛铁矿颗粒中，上翘的板块，蜿蜒的山脊，球根状边缘和磨损疲劳是风沙表面特征的特征。直的和弯曲的凹槽仅表征海洋表面纹理。为了评估沿GMC的主要运输机制，根据表面纹理观察结果，从沙丘和海滩沙子中选出了石英和钛铁矿颗粒。