gravel deposit
31sedimentary rock — Rock formed at or near the Earth s surface by the accumulation and lithification of fragments of preexisting rocks or by precipitation from solution at normal surface temperatures. Sedimentary rocks can be formed only where sediments are… …
32Spawn (biology) — The spawn (eggs) of a clownfish. The black spots are the eyes developing. Spawn refers to the eggs and sperm released or deposited, usually into water, by aquatic animals. As a verb, spawn refers to the process of releasing the eggs and sperm,… …
33Sediment — Cobbles on a beach River Rhône flowing into Lake Geneva …
34Zhoukoudian — Peking Man Site at Zhoukoudian * UNESCO World Heritage Site Country …
35Africa — /af ri keuh/, n. 1. a continent S of Europe and between the Atlantic and Indian oceans. 551,000,000; ab. 11,700,000 sq. mi. (30,303,000 sq. km). adj. 2. African. * * * I Second largest continent on Earth. It is bounded by the Mediterranean Sea,… …
36Placer mining — (pronounced plass er ) refers to the mining of alluvial deposits for minerals. This may be done by open pit (also called open cast mining) or by various forms of tunneling into ancient riverbeds. Excavation may be accomplished using water… …
37River engineering — The Los Angeles River is extensively channelized with concrete embankments. River engineering is the process of planned human intervention in the course, characteristics or flow of a river with the intention of producing some defined benefit.… …
38Mining — This article is about the extraction of geological materials from the Earth. For the municipality in Austria, see Mining, Austria. For the siege tactic, see Mining (military). For name of the Chinese emperor, see Daoguang Emperor. Simplified… …
39Clastic rock — A thin section of a clast (sand grain), derived from a basalt score. Vesicles (air bubbles) can be seen throughout the clast. Plane light above, cross polarized light below. Scale box is 0.25 mm Clastic rocks are composed of fragments, or clasts …
40Pacific Ocean — an ocean bordered by the American continents, Asia, and Australia: largest ocean in the world; divided by the equator into the North Pacific and the South Pacific. 70,000,000 sq. mi. (181,300,000 sq. km); greatest known depth, 35,433 ft. (10,800… …
