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Moeraki Boulders, New Zealand A slice of a typical carbonate-rich septarian nodule. Septarian concretions (or septarian nodules) are carbonate-rich concretions containing angular cavities or cracks (septaria; sg. septarium, from the Latin septum "partition, separating element", referring to the cracks or cavities separating polygonal blocks of ...
Nodule is also used for widely scattered concretionary lumps of manganese, cobalt, iron, and nickel found on the floors of the world's oceans. This is especially true of manganese nodules. Manganese and phosphorite nodules form on the seafloor and are syndepositional in origin. Thus, technically speaking, they are concretions instead of nodules ...
Pit 11 is now Braidwood State Fish and Wildlife Area, an Illinois state park. Fossil collecting is allowed at the park with a permit. [10] The site's importance was realized in the mid-nineteenth century: "the nodules of Mazon Creek, where fragments of plants, even of the softest texture, have been preserved in their integrity". [11]
Geodes can form in any cavity, but the term is usually reserved for more or less rounded formations in igneous and sedimentary rocks. They can form in gas bubbles in igneous rocks , such as vesicles in basaltic lava ; or, as in the American Midwest , in rounded cavities in sedimentary formations.
Debates on whether specific forms are pseudo or true fossils can be lengthy and difficult. For example, Eozoön is a complex laminated form of interlayered calcite and serpentine originally found in Precambrian metamorphosed limestones (marbles). It was at first thought to be the remains of a giant fossil protozoan (Dawson, 1865), then by far ...
Virginia's public K-12 schools are neither operated directly by the state government nor by special districts. Instead, most are organized as political subdivisions known as "school divisions" which are similar to school districts in some other states.
Gov. Glenn Youngkin has issued an executive order requiring school systems to notify parents of school-related overdoses after the Loudoun County Sheriff’s Office said there have been seven ...
The nodules form in a manner similar to pearls; there is a central object around which concentric layers are slowly deposited, causing the nodule to grow over time. The composition of the nodules can vary somewhat depending on their location and the conditions of their formation, but they are usually dominated by manganese- and iron oxides.