What can a geologist infer from a sedimentary rock with very low porosity?

A sedimentary rock with very low porosity indicates that it has tightly packed particles or cemented grains, which limits the space available for fluids like water or oil to reside. Porosity refers to the volume of voids or spaces in a rock that can hold fluids. When porosity is very low, the capacity of the rock to act as a reservoir is significantly diminished. Therefore, it would not be effective in storing significant amounts of water or oil, making the inference about its limited ability to function as a storage medium quite valid.

In contrast, the other options do not align with the fundamental properties associated with low porosity. For instance, the composition of the sedimentary rock and its organic material content cannot be directly inferred solely from low porosity, as rocks with low porosity can be composed of various materials. Additionally, the age of the rock does not necessarily correlate with its porosity and can vary widely regardless of its inferential storage capacity. Lastly, igneous rocks are characterized by their crystalline structure arising from the cooling and solidification of magma, making it inconsistent to state that low porosity would always indicate an igneous origin.