XX.—The Geochemistry of some Caledonian Plutonic Rocks: A Study in the Relationship between the Major and Trace Elements of Igneous Rocks and their Minerals

Abstract

The Caledonian plutonic rocks of Western Scotland form a well-defined group, ranging from ultrabasic to acid types, which have been studied in detail by a number of petrologists. They form intrusions of varying size, usually composite and frequently, at least, having the habit of ring complexes. The rock types include peridotites and pyroxenites, gabbros, hornblendite and appinite, appinitic diorites, pyroxene-mica diorites, hornblende-biotite diorite, various hornblende-biotite grandiorites, biotite adamellite and muscovite-biotite adamellite, while the final stage is represented by numerous veins of aplite and rare pegmatites.

Trace elements in the Singhbhum granite, India

“…In the microcline-granodiorite of Chaibasa, Sr +e shows closer affinity towards Ca +2 although in a general way it also follows K +. But here also there is a relatively greater enrichment of Ca with respect to Sr in the end-members, a situation which is the reverse of what has been observed by NOCKOLDS & MITCHELL (1948).…”

“…In the Saraikela hornblende-granodiorite, which contains Ca § in much larger quantities than K § Sr follows it more or less rigidly. But in the typical granodiorites which contain more K+-bearing minerals than Ca +e, Sr has followed in a general way the K + trend and is antipathic towards Ca § In the perthitic granodiorites of Chaibasa, Sr and K + bear an antipathic relationship, while Sr +2 and Ca +9-, especially in the first two stages, are closely related, although in the final stages Sr decreases while Ca +~ increases --a reversed relationship, as pointed out by NOCKOLDS & MITCHELL (1948), if these rocks are taken to be magmatic. In the microcline-granodiorite of Chaibasa, Sr +e shows closer affinity towards Ca +2 although in a general way it also follows K +.…”

“…EsKota (1922, p. 365) has also shown that while a Sr anorthite exists, there is no strontium mineral analogous to diopside. NOCKOLDS & MITCHELL (1948) and HEIER & TAYLOR (1959) have observed that Sr is cmnouflaged in cations of the Ca+e-bearing minerals, but as the Sr +.' ion (1.18/~) is larger it shows a relative concentration with respect to Ca +."…”

IGR - Book Section

“…Nockolds andAllen (1953, 1954) conducted special investigations on the content of dispersed elements in several series of alkalic rocks from Scotland, the Hawaiian and Polynesian Islands and the western regions of the United States. Most of their investigations were conducted on basic varieties of the alkalic class.…”

Metamorphism in the Riggins region, western Idaho

“…are largely those suggested by Goldschmidt ( 1954). Credit should also be given to the text of Rankama and Sahama (1950) and to the detailed studies of minor elements in several European provinces by Nockolds and Mitchell (1948) and Hiigi (1956).…”