Dear Colleagues.,
I ask about a very strange case that not very common but maybe some body faced it or suggest a reliable interpretation. Is it possible to find diagenetic unmetamorphosed phanerozoic carbonate sandwiched between old assemblage of precambrian volcanics that underwent metamorphism ? and there is no conglomerate or breccia lies at the contact between the basement and the sediments ? noteworthy is the presence of faults is a familiar case in that area.
i attach a simplification sketch cross-section for the case
I would like to hear from you all
Best regards
Ahmed Morad
Dear Ahmed Morad
thank you for the map.
BUt from the map, it is near impossible to answer to your question.
Y is volcaniclastics
X is metamoprphosed andesites.
Therefore X and Y are different things.
Laslty, the way you mapped carbonatic rocks indicates they are on top of both X and Y.
As I said, only outcrop pictures could help to answer.
best
I agree with Federico Lucci Federico Lucci, a photo would be really helpful.
In general, what I observe in the field is that faults in carbonates can form as very thin structures. There´s not necessarily a breccia or a large damage zone involved.
So, it´s worth having a closer look for any markers, i.e. striation, gauge.
In other words: I can not imagine that the carbonate is not metamorphosed if the contact is original.
Meta- means that the parent material has undergone a moderate physical-chemical alteration which changed the primary mineral association but not to the extent that the lithology, proper, has completely wiped out and impedes any classification, e.g., meta-basalt. As far as your sequence is concerned it seems to me very dubious this arrangment and I will not further speculate on that. Younger sediments between older volcanic rocks; If so it would be a carbonatite dyke (?)
HGD
Dear Prof. Dill,
Thanks for your interesting! Both sides are meta-, therefore it maybe contact, I could say it is bedding joint. E.g., amygules: different origin of rocks are together inside the basalt. This is way of thinking. E.g., Mr. Morad said Carbonate sandwiched, which should be analysis by geological techniques for the character: rock or vein (carbonate dyke ?= size of Carbonate band). Even though, we have observed rock or vein of Carbonate in the field. Carbonatite is out of my experience. Thanks
if it is not lithologically-based the contact, e.g., carbonatite dyke, there is only one option left a structural origin (?) if everything in the field worked its way perfectly well (?). Everything beyond that would for me speculation or poking around in the clouds
HGD
- Badges
- Science topic
- Similar topics
- Political Science
- International History and Politics
- Globalization