Webnodule, rounded mineral concretion that is distinct from, and may be separated from, the formation in which it occurs. Nodules commonly are elongate with a knobby irregular surface; they usually are oriented parallel to the bedding. Chert and flint often occur as dense and structureless nodules of nearly pure silica in limestone or chalk, where they … WebBanded iron formations (also known as banded ironstone formations or BIFs) are distinctive units of sedimentary rock consisting of alternating layers of iron oxides and iron-poor chert.They can be up to several …
Thyroid nodules - Symptoms and causes - Mayo Clinic
WebAug 24, 2024 · A concretion consists of the same material as the rock around it, plus the cementing mineral, whereas a nodule (like flint nodules in limestone) is composed of different material. Concretions can be shaped like cylinders, sheets, nearly perfect spheres, and everything in between. Most are spherical. In sedimentology and geology, a nodule is a small, irregularly rounded knot, mass, or lump of a mineral or mineral aggregate that typically has a contrasting composition, such as a pyrite nodule in coal, a chert nodule in limestone, or a phosphorite nodule in marine shale, from the enclosing sediment or sedimentary rock. Normally, a nodule has a warty or knobby surface and exists as a discret… cloak\u0027s iz
Geologic units containing Chert - USGS
WebFeb 11, 2024 · A pounding heart. Trouble sleeping. Muscle weakness. Nervousness or irritability. Also see your doctor if you have signs and symptoms that may mean your thyroid gland isn't making enough thyroid … WebAug 9, 2024 · When enough nodules accumulate, a continuous layer of chert is formed that can be seen in the stratigraphy of some sedimentary rocks. This forms a chert chemical … WebSep 30, 2024 · Dermatologists use nodules as a general term to describe any lump underneath the skin that’s at least 1 centimeter in size. It’s not a specific diagnosis. Rather, it’s used to communicate to ... cloak\u0027s iw