Abstract

Microtextures of quartz and zircon grains from the Bosque and Paseo del Mar beaches in the Gulf of Mexico were examined using a Scanning Electron Microscopy (SEM), to infer their provenance and palaeoenvironment. A total of 16 microtextures from 200 grains were identified and were grouped into mechanical, chemical, and mechanical/chemical origin. Microtextures of mechanical origin represent parallel striations (ps), cracks due to collision (ck), conchoidal fractures (cf), v-shaped marks (vs), abrasion fatigue (af), meandering ridges (mr), chattermarks (ch), curved (cg) and straight grooves (sg), which are attributed to a high-energy fluvial and sub-aqueous marine environment. Solution pits (sp), crystal overgrowth (cro), and silica globules (sgl) of chemical origin indicated precipitation and dissolution in a silica saturated marine environment. Adhered particles (ap), elongated depressions (dp), and relief are grouped as mechanical/chemical origin, suggested a sub-aqueous nearshore marine environment. Although zircon is considered as a resistant mineral, the frequency of microtextures observed was higher in zircon than in quartz. The results of this study revealed that the Los Tuxtlas volcanic field, Chiapas Massif and Oaxacan Complexes in the SW Gulf of Mexico are the potential source areas, which supplied sediments to the Paseo del Mar and Bosque beach areas.

Highlights

• Microtextures of quartz and zircon grains in the Bosque and Paseo del Mar beaches in the SW Gulf of Mexico were analyzed.

• Frequency of microtextures are higher in zircon than in quartz grains revealed that microtextures are independent of grain hardness.

• The dominance of microtextures of chemical origin in the Paseo del Mar beach suggested a low-energy environment with carbonate rich sediments.

• Chiapas Massif and Oaxacan Complexes are identified as the potential source areas, which supplied sediments to the beach areas.

中文翻译：

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墨西哥湾Paseo del Mar和Bosque海滩石英和锆石晶粒中的微纹理的来源及其古环境意义

摘要

使用扫描电子显微镜（SEM）检查了墨西哥湾博斯克海滩和Paseo del Mar海滩的石英和锆石晶粒的微观结构，以推断其起源和古环境。从200个晶粒中总共鉴定出16个微纹理，并将其分为机械，化学和机械/化学起源。机械起源的微观纹理表示平行条纹（ps），由于碰撞而产生的裂纹（ck），贝壳状裂缝（cf），v形痕迹（vs），磨损疲劳（af），曲折脊（mr），颤动痕迹（ch），弯曲（cg）和直槽（sg），这归因于高能量的河流和水下水环境。化学来源的溶液坑（sp），晶体过度生长（cro）和二氧化硅小球（sgl）表明在二氧化硅饱和的海洋环境中沉淀和溶解。粘附的颗粒（ap），拉长的凹陷（dp）和浮雕被归类为机械/化学来源，表明水下近海水域环境。尽管锆石被认为是一种抗矿物，但在锆石中观察到的微观纹理的频率要比在石英中高。这项研究的结果表明，墨西哥西南海湾的Los Tuxtlas火山场，恰帕斯断层块和Oaxacan复合体是潜在的源区，向Paseo del Mar和Bosque海滩地区提供了沉积物。

强调

• 分析了墨西哥SW海湾的Bosque和Paseo del Mar海滩的石英和锆石晶粒的微观结构。

• 锆石中微纹理的频率高于石英晶粒，这表明微纹理与晶粒硬度无关。

• 在Paseo del Mar海滩中，化学起源的微观纹理占主导地位，这表明低能量环境具有富含碳酸盐的沉积物。

• 恰帕斯州地块和瓦哈卡复合体被确定为潜在的源区，向海滩地区提供了沉积物。