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A bedrock mortar (BRM) is an anthropogenic circular depression in a rock outcrop or naturally occurring slab, used by people in the past for grinding of grain, acorns or other food products. [1] There are often a cluster of a considerable number of such holes in proximity indicating that people gathered in groups to conduct food grinding in ...
Platanus occidentalis, also known as American sycamore, American planetree, western plane, [2] occidental plane, buttonwood, and water beech, [3] is a species of Platanus native to the eastern and central United States, the mountains of northeastern Mexico, extreme southern Ontario, [4] [5] and extreme southern Quebec. [6]
Researchers at McGill University found a rock with a very old model age for extraction from the mantle (3.8 to 4.28 billion years ago) in the Nuvvuagittuq greenstone belt on the coast of Hudson Bay, in northern Quebec; [2] the true age of these samples is still under debate, and they may actually be closer to 3.8 billion years old. [3]
As North America separated from Africa a small portion of the African Plate detached and was carried away with the North American Plate. This provided some of the foundation upon which Florida now rests. [6] The emergent portion of the platform was created during the Eocene to Oligocene as the Gulf Trough filled with silts, clays, and sands.
The soft stone is easily carved and is not degraded by heating. The slick surface of soapstone allows the finished object to be easily removed. Welders and fabricators use soapstone as a marker due to its resistance to heat; it remains visible when heat is applied. It has also been used for many years by seamstresses, carpenters, and other ...
[1] Primitive rocks "have never been heated much, although some of their constituents may have been quite hot early in the history of our Solar System. Primitive rocks are common on the surfaces of many asteroids, and the majority of meteorites are primitive rocks." [1]: 145 Widmanstätten pattern in an iron-rich meteorite
Basement rock is the thick foundation of ancient, and oldest, metamorphic and igneous rock that forms the crust of continents, often in the form of granite. [2] Basement rock is contrasted to overlying sedimentary rocks which are laid down on top of the basement rocks after the continent was formed, such as sandstone and limestone.
The geology of Anglesey, the largest (714 km 2) island in Wales is some of the most complex in the country. Anglesey has relatively low relief, the 'grain' of which runs northeast–southwest, i.e. ridge and valley features extend in that direction reflecting not only the trend of the late Precambrian and Palaeozoic age bedrock geology but also the direction in which glacial ice traversed and ...