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Powell Butte is a cinder cone butte [4] and is part of the Plio-Pleistocene Boring Lava Field, [4] a group of volcanic cones that got their name from the low, forested Boring Hills formation. [5] Located in the Portland Basin, the Boring Lava Field consists of monogenetic volcanic cones that appear as hills throughout the area, reaching heights ...
Evidence of the oldest flows can be seen at Lava Point and rocks from the youngest are found at the lower end of Cave Valley. [22] > Some cinder cones were constructed much later in the southwest corner of the park. [22] Some of these lava flows blocked rivers and streams, impounding small lakes and ephemeral ponds in the process.
Amethyst crystals – a purple quartz Apophyllite crystals sitting right beside a cluster of peachy bowtie stilbite Aquamarine variety of beryl with tourmaline on orthoclase Arsenopyrite from Hidalgo del Parral, Chihuahua, Mexico Aurichalcite needles spraying out within a protected pocket lined by bladed calcite crystals Austinite from the Ojuela Mine, Mapimí, Durango, Mexico Ametrine ...
The geological term cinder is synonymous and interchangeable with scoria, though scoria is preferred in scientific literature. [ 2 ] [ 4 ] The word comes from Greek σκωρία, skōria , rust. In earlier terminology, scoria was usually defined with a size range, e.g. 2 to 24 mm (0.079 to 0.945 in) in diameter, but neither color nor ...
The Hawaiian fishpond was primarily a grazing area in which the fishpond-keeper cultivated algae; much in the way cattle ranchers cultivate grass for their cattle. [3] The porous lava walls let in seawater (or sometimes fresh or brackish water, as in the case of the "Menehune" fishpond near Līhuʻe, Kauaʻi), but prevent the fish from escaping.
Its last eruptions took place about 57,000 years ago at the Beacon Rock cinder cone volcano. The individual volcanic vents of the field are considered extinct, but the field itself is not. The Boring Lava Field covers an area of about 1,500 square miles (3,900 km 2) and has a total volume of 2.4 cubic miles (10 km 3). This region sustains ...
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Phosphorite – Sedimentary rock containing large amounts of phosphate minerals – A non-detrital sedimentary rock that contains high amounts of phosphate minerals; Sandstone – Type of sedimentary rock; Shale – Fine-grained, clastic sedimentary rock; Siltstone – Sedimentary rock which has a grain size in the silt range