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Palaeoenvironment and provenance signatures inferred from quartz grain surface features: A case study from Huatabampo and Altata beaches, Gulf of California, Mexico
Journal of South American Earth Sciences ( IF 1.8 ) Pub Date : 2021-06-23 , DOI: 10.1016/j.jsames.2021.103441
J. Madhavaraju , John S. Armstrong-Altrin , R. Arthur James , S.M. Hussain

Microtextures on quartz grains from the Huatabampo (HB) and Altata (AA) beaches, Gulf of California, were analyzed by a scanning electron microscopy (SEM) to infer the depositional history and provenance. In total, 41 microtextures were identified and grouped as mechanical, mechanical/chemical, and chemical mode of origins. Among them, twenty-three microtextures represent mechanical, eight represent mechanical/chemical, and ten represent chemical origin. The microtextures of chemical origin were further classified as dissolutional and precipitational origins. Oriented etch pits, solution pits, solution crevasses, and scaling are classified as of dissolutional origin. Silica globules, silica flower, silica pellicles, crystalline overgrowth, trapped diatoms, and halite crystals are grouped as chemical precipitational origin. The V-shaped marks, straight and curved scratches revealed the combination of fluvial and high energy subaqueous beach environments. The low frequencies of upturned plates, abrasion fatigue, meandering ridges, crescentic percussion marks, bulbous edges and elongated depressions suggest the low abundance of sediments derived by aeolian transport. The microtextures of chemical origin in few grains indicated the diagenetic processes in a silica saturated intertidal zone. The quartz grains from HB and AA beaches reveal varying sizes of conchoidal fractures indicate that they were derived mainly from crystalline source rocks. The association of straight and arcuate steps along with conchoidal fractures further support that the studied quartz grains were liberated from crystalline rocks. The dominance of angular to sub-angular grains indicates short transport and rapid deposition. In addition, straight and arcuate steps are delicate features which might have been destroyed during long transportation. Thus, the presence of straight and arcuate steps features together with angular to sub-angular grains support a nearby source.



中文翻译:

从石英颗粒表面特征推断出的古环境和来源特征:墨西哥加利福尼亚湾瓦塔班波和阿尔塔塔海滩的案例研究

通过扫描电子显微镜 (SEM) 分析了来自加利福尼亚湾华塔班波 (HB) 和阿尔塔塔 (AA) 海滩的石英颗粒的微观纹理,以推断沉积历史和来源。总共确定了 41 种微观纹理,并将其分为机械、机械/化学和化学起源模式。其中,二十三个微观纹理代表机械,八个代表机械/化学,十个代表化学起源。化学起源的微观结构进一步分为溶解起源和沉淀起源。定向蚀刻坑、溶液坑、溶液裂缝和结垢被归类为溶解源。二氧化硅球、二氧化硅花、二氧化硅薄膜、结晶过度生长、捕获的硅藻和岩盐晶体被归类为化学沉淀来源。V字形标志,笔直和弯曲的划痕揭示了河流和高能量水下海滩环境的结合。低频率的上翻板块、磨损疲劳、蜿蜒的山脊、新月形的撞击痕迹、球根状边缘和拉长的洼地表明风积输送产生的沉积物含量低。少数颗粒中化学成因的微观结构表明了二氧化硅饱和潮间带中的成岩过程。HB 和 AA 海滩的石英颗粒显示出大小不一的贝壳状裂缝,表明它们主要来源于结晶性烃源岩。直线和弓形台阶与贝壳状断裂的关联进一步支持所研究的石英颗粒是从结晶岩中释放出来的。角状到亚角状颗粒的优势表明短输运和快速沉积。此外,笔直和弧形的台阶是在长途运输中可能被破坏的精致特征。因此,直线和弓形台阶特征的存在以及角到亚角的晶粒支持附近的源。

更新日期:2021-06-29
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