Quaternary refers to the period of Earth's history from about 2 million years ago to the present; also, the rocks and deposits of that age. Quaternary refers also to a geologic period that occurred roughly 1.6 million years ago to today. During much of this period continental glaciers in the Northern Hemisphere covered large regions of land surface in the high and mid-latitudes. Homo sapiens appear about 200,000 years BP (before present) and become the first species to alter the Earth's environment on a large-scale.

-see also:
"Quaternary" is in the HS Code "2923"
  Quaternary Ammonium Salts And Hydroxides ; Lecithins And Other Phosphoaminolipids
Ref: 86255/2006-09-13


You have no rights to post comments

Related Articles

Fatty Amines and Ammonium slats ■■■■
Fatty Amines and Ammonium slats: Our products mainly involved in :1£¬Quaternary Ammonium Salts: Ester . . . Read More
Fossil fuel at environment-database.eu■■■■
A fossil fuel is a fuel, such as coal, oil, and natural gas, produced by the Decomposition of ancient . . . Read More
Monument ■■■■
Monument: In the industrial or industry context, a "monument" typically refers to a fixed reference point . . . Read More
Gypsum ■■■■
Gypsum refers to a naturally occurring crystalline form of calcium sulfate in which each molecule of . . . Read More
Basalt ■■■■
Basalt is described as a dark igneous rock. Basalt originates from lava that has extruded onto the surface . . . Read More
Reef at maritime-glossary.com■■■■
A reef is a rock, sandbar, or other feature lying beneath the surface of the water (80 meters or less . . . Read More
Coal ■■■■
Coal refers to a combustible black or brownish-black sedimentary rock composed mostly of carbon and hydrocarbons . . . Read More
Cattle ■■■■
Cattle (colloquially cows) are the most common type of large domesticated ungulates. They are a prominent . . . Read More
Ammonia, NH3 ■■■
Ammonia, NH3 in its pure state and under usual environmental conditions, ammonia exists as a colourless, . . . Read More
Sell Cosmetics Products ■■■
Sell Cosmetics Products: We are whole manufacturers importer & Exporter (ISO9001), which is one of the . . . Read More