kvartaariset

Kvartaariset is a Finnish term used to describe things related to the concept of quaternary, and it appears in several scientific contexts. The word is the plural form of kvartaarinen, and in practice it is applied to items, periods, or compounds that involve fourfold or four-part characteristics.

In geology and paleontology, kvartaarinen refers to the Quaternary period, the most recent major division of the Neogene. The Quaternary began about 2.58 million years ago and continues to the present. It encompasses the Pleistocene and Holocene epochs and is characterized by repeated climatic fluctuations, including Ice Ages, as well as the emergence and spread of Homo sapiens. The period has shaped modern landscapes, sea levels, and ecosystems and hosts the developments of human civilization.

In chemistry, kvartaariset ammoniumyhdisteet (quaternary ammonium compounds) are a class of salts in which a nitrogen atom bears four organic substituents and carries a positive charge. These compounds are commonly used as surfactants, disinfectants, and antiseptics due to their surface-active properties and antimicrobial activity. Typical examples include cetyltrimethylammonium salts and benzalkonium salts. Kvartaariset yhdisteet are generally soluble in water and stable under normal conditions, making them widespread in cleaning products, personal care items, and clinical settings.

Outside these fields, the term can appear in other disciplines to denote fourfold or four-part characteristics, reflecting the core meaning of four. Overall, kvartaariset signals a quaternary or four-fold aspect in scientific usage.