This study provides new insights about depositional paleoenvironments through siliciclastic microfacies, carbonate microfacies, and biofacies analysis from sedimentary formations of the lower and middle Cambrian (Stage 4–Wuliuan), exposed in central Sonora, northern Mexico. Results of the petrographic analysis of 48 samples revealed the following lithologies: quartzarenite, oncolytic rudstone, grainstone-packstone, wackestone, mudstone, and to a lesser extent sandy limestone. Two siliciclastic microfacies were identified: (A) quartzarenite with cross-bedded and horizontal stratification deposited in an intertidal and supratidal environment; and (B) massive quartzarenite with Skolithos ichnofacies deposited in subtidal and intertidal environments. Four carbonate microfacies were identified: microfacies 1 is a sandy limestone with trilobite fragments; microfacies 2 is a grainstone with intraclasts, salterellids, hyolithids, trilobites, and echinoderms plates; microfacies 3 is an oncolytic rudstone consisting of microbes and abundant echinoderms plates; and microfacies 4 is a packstone-grainstone with abundant ooids, trilobite fragments, and echinoderm plates. Two biofacies were identified: Agnostid-polymeroid biofacies with predominance of the trilobites Pentagnostus, Bathyuriscus, Oryctocephalites, and Elrathina; and Pagetia biofacies with abundant trilobites of the genera Pentagnostus, Pagetia and Elrathina. It is concluded by the sedimentation model that changes in sea level is the most important parameter in determining the siliciclastic microfacies, carbonate microfacies and biofacies; as well as the depositional environments that vary from the coastline (subtidal to supratidal) to shallow-water open circulation marine platform with low and high energy waters. The Cambrian deposits of northern Mexico are correlated with the deposits of California and Nevada (USA), as well as to the Precordillera (Argentina), where the species in common show a strong affinity.

本研究通过对墨西哥北部索诺拉中部出露的下寒武统和中寒武统（第 4 期-五六）沉积地层的硅质碎屑微相、碳酸盐微相和生物相分析，提供了关于沉积古环境的新见解。48 个样品的岩相分析结果揭示了以下岩性：石英砂砾岩、溶瘤砾岩、颗粒岩-填充岩、泥灰岩、泥岩，以及较小程度的砂质石灰岩。确定了两个硅质碎屑微相：（A）石英砂砾岩，沉积在潮间带和潮上带环境中，具有交叉层状和水平分层；(B) 带有Skolithos的块状石英砂岩沉积在潮下带和潮间带环境中的岩相。共识别出4个碳酸盐微相：微相1为含三叶虫碎片的砂质石灰岩；微相 2 是一种颗粒岩，具有内碎屑、盐藻、水石、三叶虫和棘皮动物板块；microfacies 3 是一种由微生物和丰富的棘皮动物板块组成的溶瘤地心石；微相 4 是一种富含鲕粒、三叶虫碎片和棘皮动物板块的颗粒岩。确定了两个生物相：以三叶虫Pentagnostus、Bathyuriscus、Oryctocephalites和Elrathina为主的 Agnostid-polymeroid生物相；和Pagetia 生物相，具有丰富的三叶虫属Pentagnostus、Pagetia和Elrathina。由沉积模型得出，海平面变化是决定硅质碎屑微相、碳酸盐微相和生物相的最重要参数；以及从海岸线（潮下到潮上）到具有低能和高能水域的浅水开放循环海洋平台的不同沉积环境。墨西哥北部的寒武纪矿床与加利福尼亚州和内华达州（美国）的矿床以及与 Precordillera（阿根廷）的矿床相关，那里的物种共同表现出很强的亲和力。