76 ' I'FNTTI RSKOLA. M.-N. Kl. 



date, |)i obahiv In mi lli< l;isl staj^e ol consolidation, arc ciiihcfldcfl in the 

 mass and appear ciilirclv nntoiichcfl ]>\ {])<■ chances. 



The crN'slals ol' garnet an- surrounded hy kcls'phitc, composed ol 

 dark i;i-ccn liornhlciidc intci-i;ro\vn willi a few feldspar rods in a sym- 

 plcctic manner. 



V'ei-y strikinj.; is the alteration of rutile into leucoxenedike titanite, here 

 occurrint^ at its first stage, as thin /ones round some of the brown grains. 



In another specimen we linil the amphiholitization a little more de- 

 veloped dig. 11, pi. ID. The symplectite, with preserved structure, ha.s 

 tieen entirely uralitized. At places the symplectic structure has become a 

 little coarser. 



But little i-cmains of the grains of gai-net; the greater part has been 

 altered into gi-een hoi-nhlende with svmplectic plagioclase and frequent 

 octahedra of magnetite. 



About a half of the rutile has been altered into leuco.xene (with 

 aggregate-polarization). Ihose crystals oi rutile enclosed in the unaltei'ed 

 garnet s'how no change whatever. 



At further stages the structure of the hornblende-plagioclase-symplectite 

 begins to alter. The hornblende, faithful to its nature, tends to develope 

 idioblastic prism faces and to grow in length (hg. 12, pi. 111. The rod- 

 shape of the plagioclase hereby becomes destroyed; this mineral then hits 

 up the interstices between the hornblende prisms and soon loses its indi- 

 viduality. The structure becomes more and more like that of a usual 

 granoblastic amphibolite. But the aggregates of dark gieen hornblende with 

 ii'on ore, i. e. the kelyphite, representing the earlier garnet of which a kernel 

 may or may not be pi^eserved, and the parallel or subparallel groups of 

 the hornblende prisms in the ground-mass, the substitute of the earlier 

 diopside-plagioclase-intergrowth, remind us that we have to do with an 

 amphibolitized eclogite. 



Laura Hezner' distinguishes two kinds ot" amphiholitization of eclogites : 

 "Typus I. Die amphibolisierung der Omphazite bleibt an feine Wrfaserung 

 geknüpft . . . Theoretisches Endglied (nui- tleckweise erreicht); porphvr- 

 artiger Amphibolit mit nephritischer Cirundmasse und Einsprengungen aus 

 rundlichen Hornblendeaggregaten . . ."' 



"Typus II. Die Ausfaserung der Omphazite xergröbert sich mit der 

 Entfernung \om Pyroxenkei-n und geht in ktu-nige oder leistige grüne 

 Hornblende über . . . 'I'heoretisches Endglied: Körniger Amphibolit . . ." 



Hezner's type I is identical with what has been just described, although 

 she has not followed its de\elopment in such a detail as I have done. As 

 to type II, I have not observed, in the Norwegian eclogites, that common 

 granular amphibolites ha\-e indeed developed in that way,, although it is not 

 impossible. Granular amphibolite is of common occurrence in association 



• I.oc. cit. 11'. M. P. M. -jj, 1903. p. 505). 



