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The Columbia River Basalt Group (including the Steen and Picture Gorge basalts) extends over portions of four states. The Columbia River Basalt Group (CRBG) is the youngest, smallest and one of the best-preserved continental flood basalt provinces on Earth, covering over 210,000 km 2 (81,000 sq mi) mainly eastern Oregon and Washington, western Idaho, and part of northern Nevada. [1]
The earliest stone tools to date have been found at the site of Lomekwi 3 (LOM3) in Kenya and they have been dated to around 3.3 million years ago. [1] The archaeological record of lithic technology is divided into three major time periods: the Paleolithic (Old Stone Age), Mesolithic (Middle Stone Age), and Neolithic (New Stone Age).
The Ringold Formation represents sand and gravel placed by the Columbia River between 9 and 3 million years ago. These deposits overlay cooled lava erupted as part of the Columbia River Basalt Group, a type of volcanic eruption known as flood basalts erupting from fissures across eastern Washington and Oregon that were unrelated to the Cascade Range. [11]
The stone tools may have been made by Australopithecus afarensis, the species whose best fossil example is Lucy, which inhabited East Africa at the same time as the date of the oldest stone tools, a yet unidentified species, or by Kenyanthropus platyops (a 3.2 to 3.5-million-year-old Pliocene hominin fossil discovered in 1999).
In archaeology, ground stone is a category of stone tool formed by the grinding of a coarse-grained tool stone, either purposely or incidentally. Ground stone tools are usually made of basalt , rhyolite , granite , or other cryptocrystalline and igneous stones whose coarse structure makes them ideal for grinding other materials, including ...
To create this tool, one would have to use a hammerstone to chip away flakes on the stone to create a side of the stone with a very sharp edge, allowing for the cutting and hacking of an object. This is a unique type of lithic reduction, as only a single side of the stone is retouched to produce the cutting surface of the stone. The side that ...
A megastructure found in the Baltic Sea may represent one of the oldest known hunting structures used in the Stone Age — and could change what’s known about how hunter-gatherers lived around ...
The Columbia Plateau is an important geologic and geographic region that lies across parts of the U.S. states of Washington, Oregon, and Idaho. [1] It is a wide flood basalt plateau between the Cascade Range and the Rocky Mountains , cut through by the Columbia River .