الفهرس 
General geology and samplingOnly 14 pages are availabe for public view
 |  | from | 149 |  |  |
| | | from | 149 | | |
Abstract
The two s t u d i e d c h r o m i t e o c c u r r e n c e s ( S i f e i n a n d Dung a s h ) a r e from t h e P r e c a m b r i a n b a s e m e n t c o m p l e x . Single-pha s e d homogeneous c h r o m i t e ( f e r r i m a g n e t i c p h a s e ), w i t h a C u r i e t e m p e r a t u r e b e t w e e n 1 0 0 - 120i~s~ t h e p r i n c i p a l ma g n - e t i c m i n e r a l i n S i f e i n o c c u r r e n c e . The c o m p l i c a t e d b e h a v i o u r o f some Dungash s i t e s p o s s i b l y r e f l e c t s p r o c e s s e s w h i c h o c c u r d u r i n g p a r t i a l m o b i l i z a t i o n , i n w h i c h r e c r y s t a l l i z a t i o n a n d m i g r a t i o n o f a t o m s may h a v e t a k e n p l a c e r e s u l t i n g inmuch o f t h e a l t e r a t i o n and e x s o l u t i o n t e x t u r e s , w i t h a c u r i e t e m p e r a - t u r e b e t w e e n 1 8 0 - 200’~. M a g n e t i c f a b r i c m e a s u r e m e n t s s h o w e d u n r e l i a b l e r e s u l t s f o r t h e m a j o r i t y o f Dungash c h r o m i t e w h i c h was a t t r i b u t e d t o t h e v e r y low v a l u e s o f m a g n e t i c s u s c e p t i b i l i t y w h i c h s e e m e d c l o s e t o t h e i n s t r u m e n t n o i s e l e v e l . The S i f e i n c h r o m i t e , on t h e o t h e r h a n d , showed f e a t u r e s o f a f a b r i c t h a t c o u l d b e d e s - c r i b e d as a weak s e c o n d a r y f a b r i c w i t h some r e m a i n i n g f e a t u r e s o f a p r e - e x i s t i n g p r i m a r y f a b r i c . The f a b r i c , g e n e r a l l y , had no d e f i n i t e p a t t e r n w h e r e t h e d i f f e r e n t AMS a x e s were moderatly s c a t t e r e d . The AMS p a r a m e t e r s f o r t h e s e c h r o m i t e s i n d i c a t e l o w d e g r e e o f d e f o r m a t i o n a s t h e y g a v e l o w d e g r e e s o f anisotr o p y . A l s o a l l t h e e l l i p s o i d s r e s u l t e d f r o m t h e s e m e a s u r e m e n t s h o w e d d o m i n a n t f o l i a t i o n o v e r l i n e a t i o n .