Sandstone - Types of Sandstone

Types of Sandstone

All sandstone are composed of the same general minerals. These minerals make up the framework components of the sandstones. Such components are quartz, feldspars, and lithic fragments. Matrix may also be present in the interstitial spaces between the framework grains. Below is a list of several major groups of sandstones. These groups are divided based on mineralogy and texture. Even though sandstones have very simple compositions which are based on framework grains, geologists have not been able to agree on a specific, right way, to classify sandstones. Sandstone classifications are typically done by point-counting a thin section using a method like the Gazzi-Dickinson Method. The composition of a sandstone can have important information regarding the genesis of the sediment when use with a triangle Quartz, Feldspar, Lithic Fragment (QFL diagrams). Many geologist however do not agree on how to separate the triangle parts into the single components so that the framework grains can be plotted. Therefore, there have been many published ways to classify sandstones, all of which are similar in their general format.

Visual aids are diagrams that allow geologists to interpret different characteristics about a sandstone. The following QFL chart and the sandstone provenance model correspond with each other therefore, when the QFL chart is plotted those points can the be plotted on the sandstone provenance model. The stage of textural maturity chart illustrates the different stages that a sandstone goes through.

• A QFL chart is a representation of the framework grains and matrix that is present in a sandstone. This chart is similar to those used in igneous petrology. When plotted correctly, this model of analysis creates for a meaningful quantitative classification of sandstones.
• A sandstone provenance chart allows geologists to visually interpret the different types of places sandstones can originate from.
• A stage of textural maturity is a chart that shows the different stages of sandstones. This chart shows the difference between immature, submature, mature, and supermature sandstones. As the sandstone becomes more mature grains become more rounded, and there is less clay that makes up the matrix of the rock.