(2) Ijolite refers to a series of
plutonic rocks containing nepheline and 30-60% mafic minerals, generally clinopyroxene, and including titanite, apatite and sometimes andradite (Jackson, 1997).
The oldest
plutonic rocks in the Central plutonic belt are foliated granites that generally yield Floian to Darriwilian (Early to Middle Ordovician) U-Pb (zircon) ages (Whalen 1993; Whalen et al.
In addition, it is found that extrusive rocks (e.g., basalt and dacite) have much higher [kappa] compared to
plutonic rocks; hypabyssal and pyroclastic rocks have relatively lower [kappa] (Table 2).
Plutonic rock fragments and schist-slate fragments are present, especially towards the south and the top of the formation (AGE, BLA, SAN, ESP, VUR) (Figs.
Geology, petrology, and geochemistry of the Neoproterozoic volcano
plutonic rock association of the Indian Shield extension in Pakistan.
The intermediate
plutonic rock samples, although having similar total REE to the gabbroic sample (27-33 ppm, from 4 to 18 times the chondritic abundances), have fractionated REE patterns an enrichment of the LREE compared to the HREE ([[La/Yb].sub.N] = 2.69-3.71, Fig.
Two leucogranite salnples have [[delta].sup.2][H.sub.WR] values of-60 and -56[per thousand], whereas values are lower for other
plutonic rock types (-78 to -61[per thousand]).
Plutonic rock geochemical and isotopic evidence for a transition from arc (ca.
Major and trace elements study signify one common primary magma source composition for the
plutonic rocks of the Chilas complex.
(iii) The northern domain consists of subordinate 830 Ma old metavolcanic rocks of tholeitic and alkaline affinities, which are associated with metasediments known as the Poli series and widespread 630-660 Ma old calc-alkaline
plutonic rocks known as orthogneisses, which result from a major crustal accretion episode.