海砂粒级划分标准和沉积物命名方法探讨*

近年来, 随着海砂资源需求激增和勘查开发快速发展, 解决海砂调查研究领域中海砂命名混乱的问题迫在眉睫。本文在总结多年海砂调查经验和前人研究成果的基础上, 分析对比已有粒级划分标准和沉积物命名方法的特点, 提出一套适用于海砂的粒级划分标准和命名方法。基于伍登-温特沃斯(Udden-Wentworth)等比制φ值粒级标准, 提出将海砂沉积物粒级划分为砾(>2mm)、砂(2~0.063mm)和泥(<0.063mm)3大类, 二级细分为9小类; 基于优势粒级法思想, 将砾、砂和泥作为三个分类端元, 提出“砾-砂-泥三角图解+砂、砾质沉积物细分命名”的海砂沉积物分类方案, 体现了“对砂、砾质沉积物细化其名, 对泥质沉积物简化其名”的思想。该命名方法直观地反映了海砂的粒级组成和含量, 同时较好地兼顾了海砂命名的沉积学涵义和实际应用需求。

Discussion on grain-size grading scale and sediment classification for marine sand and gravel

In recent years, the demand for marine sand and gravel increased sharply. Accordingly, its exploration and exploitation developed rapidly. To avoid naming confusion in the field of marine sand and gravel investigation and research, we analyzed the characteristics of the existing grading scales and sediment classification schemes based on years of marine sand and gravel investigation experience and previous research results, and put forward a set of grading scale and sediment naming method suitable for marine sand and gravel. Based on the Udden-Wentworth geometric series grading scale (phi scale), we proposed a particle size grading scale for marine sand- and gravel-related sediments, which divides the particle size grades into three categories of gravel (>2 mm), sand (2~0.063 mm) and mud (<0.063 mm), and nine subcategories. Based on preponderant grain-size composition, we proposed a “gravel-sand-mud triangular diagram + detailed naming of sandy and gravelly sediment” classification scheme, which embodies the idea of “detailed naming of sandy and gravelly sediments while simplifying naming of muddy sediments.” This can directly reflect the grain-size composition and content of marine sand and gravel.