Universal Product Code. The Universal Product Code (UPC) is a barcode symbology that is widely used in the United States, Canada, United Kingdom, Australia, New Zealand, in Europe and other countries for tracking trade items in stores. UPC (technically refers to UPC-A) consists of 12 numeric digits, that are uniquely assigned to each trade item. Along with the related EAN barcode, the UPC is the barcode mainly used for scanning of trade items at the point of sale, per GS1 specifications.
A-C. Abyssal Plain The flat area of the ocean basins between oceanic ridges and trenches or passive margins. Average depth of the abyssal plain is 4km below sea level. Typically the sedimentary rocks forming here are black shales and turbidites.Accretionary Wedge (prism) A zone of deformed sediment made up of thrust slices scraped off a subducting oceanic plate and added onto the over-riding plate.ontinental Crust A collective term for the crust that forming the continents; it has an average thickness of 35 km but can be up to 70 km under mountain ranges. Typically the composition is granitic with a density of 2.7 meaning that it is too buoyant to be subducted at convergent (destructive) plate margins.
When this landmass started to split, gashes in Earth's crust called rifts opened up along pre-existing weaknesses. One of these gashes, called the West Africa Rift System, started to tear apart the future Sahara desert. Two more rifts formed along the future boundaries of South America and Africa.Imagine three rift zones, two lined up essentially north-south and one pointing east-west. These alignments are key to explaining why the continents broke apart the way they did, according to a study published March 6 in the journal Geology.he mantle is the hotter layer of rock beneath Earth's crust. The crust often breaks apart at three-pronged junctions, such as the triple rift that formed between Africa-South America, and it's not uncommon for one rift to fail to develop.