Different Localities of Potassium-Rich Silica-Undersaturated Igneous Rocks and Their Silica-Rich Variants - Origin of Potassium-rich Silica-deficient Igneous Rocks - page 87

Chapter 4
Different Localities of Potassium-Rich
Silica-Undersaturated Igneous Rocks
and Their Silica-Rich Variants

Silica-undersaturated potassium-rich igneous rocks and their derivants were earlier
considered to be a rare group of rocks occurring in widely scattered localities all
over the world (Turner and Verhoogen 1960). During the last three decades
however, a large number of localities have been described, where these rocks are
reported. They are therefore, much more abundant and widespread than previously
thought of (Gupta and Fyfe 2003).
As a matter of fact they are found in all the continents. In Asia, they have been
described from Wudalianchi, Erkeshan and Chi-hsing Shan of Manchuria, China
and Yengbejin rift valley of the Tibetan plateau. The notable localities from
Indonesia include, Mount Mouriah, Palialian, T Tülering and Ringgit Beser complex

of Java. In India, they have been described from Bokaro, Jharia and Raniganj
sedimentary basins of the Damodar Valley Coal

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fields, where they occur as innu-
merable dykes and sills of lamprophyres and lamproites.
In Australia the two well-known localities are, West Kimberly Province of north-
west Australia and New South Wales, located towards south east of that continent.
The most well known localities of potassic lavas in Africa include:

1. Ruwenzori and the localities adjoining Western Rift of Central Africa,
2. Birunga volcanic province, and
3. The Kapamba region of Luwangwa Valley, Zambia.

In Europe, they occur in the Murcia and Almaria Province of Spain, East Eifel
province of Germany and many localities of Italy. Some of the important Italian
localities include, Monti Vulsini, Vico, Monti Sabatini, Alban Hills, the Phlegrean
Fields, Roccaman na and the Somma-Vesuvious region. They also occur in the

Massif Central region of France. In the United States of America, they have been
described from Highwood Mountains (Montana), Hopi Butte (Utah), Navajo
(Arizona) and Leucite Hills of Wyoming, Yoshemite National Park, Sierra Nevada
and Deep Spring Valley, located east of Sierra Nevada.
A great deal of information about the occurrence of K-rich silica-undersaturated
rocks of the former USSR can be obtained from Kogarko et al. (1995). Their
description shows that there are at least thirty localities, where K-rich silica-
undersaturated rocks are found. These localities occur in the petrographic provinces