Mohammad Ashouri - Master of Natural Geography, Geomorphology, Faculty of Planning and Environmental Sciences, Tabriz University, East Azarbaijan Province, Iran

The Silk Road was a network of Eurasian trade routes that was active from the ۲nd century BC to the mid-۱۵th century. More than ۶,۴۰۰ kilometers (۴,۰۰۰ miles) long, the Silk Road played a central role in facilitating economic, cultural, political, and religious interactions between East and West. The name "Silk Road" was first coined in the late ۱۹th century. Now some experts use "Silk Roads" instead of "Silk Road". They think that this new term is better at indicating the many routes over land and sea that connect different parts of Asia, Africa and Europe. Hydrothermal synthesis includes the various techniques of crystallizing substances from high-temperature aqueous solutions at high vapor pressures; also termed "hydrothermal method". The term "hydrothermal" is of geologic origin. Geochemists and mineralogists have studied hydrothermal phase equilibria since the beginning of the twentieth century. George W. Morey at the Carnegie Institution and later, Percy W. Bridgman at Harvard University did much of the work to lay the foundations necessary to containment of reactive media in the temperature and pressure range where most of the hydrothermal work is conducted. Geochemical modeling or theoretical geochemistry is the practice of using chemical thermodynamics, chemical kinetics, or both, to analyze the chemical reactions that affect geologic systems, commonly with the aid of a computer. It is used in high-temperature geochemistry to simulate reactions occurring deep in the Earth's interior, in magma, for instance, or to model low-temperature reactions in aqueous solutions near the Earth's surface, the subject of this article. Geochemical modeling is used in a variety of fields, including environmental protection and remediation, the petroleum industry, and economic geology. Models can be constructed, for example, to understand the composition of natural waters; the mobility and breakdown of contaminants in flowing groundwater or surface water; the ion speciation of plant nutrients in soil and of regulated metals in stored solid wastes; the formation and dissolution of rocks and minerals in geologic formations in response to injection of industrial wastes, steam, or carbon dioxide; the dissolution of carbon dioxide in seawater and its effect on ocean acidification; and the generation of acidic waters and leaching of metals from mine wastes.

Hydrothermal, Geochemical Alteration, Patterns, Abrisham Rood