Nodosariid

Nodosariid is a term used in the field of geology to describe a type of sedimentary structure characterized by the presence of small, nodular concretions within a sedimentary rock. These concretions, often composed of minerals such as pyrite, siderite, or calcite, are typically spherical or oval in shape and can vary in size from a few millimeters to several centimeters in diameter. Nodosariid structures are often found in marine sediments, particularly in environments with high organic matter content, and are believed to form through diagenetic processes involving the precipitation of minerals around organic matter or other nuclei.

The term "nodosariid" is derived from the Latin word "nodus," meaning "knot," and the Greek word "sarx," meaning "flesh," reflecting the nodular appearance of these structures. Nodosariid concretions can provide valuable information to geologists about the depositional environment, diagenetic history, and potential hydrocarbon reservoirs of the rock in which they are found. They are commonly studied in the context of sedimentary petrology and stratigraphy.