Dear Ahmad,

That's a nice question!

In general, the foliations in granitoids can form by magmatic flow, ‘submagmatic flow’, high-temperature solid-state deformation and moderate- to low-temperature solid-state deformation (Paterson et al, 1989).

Hi Ahmad, on your photos I cannot see UST textures which are commonly found at the top of fractionating magma chambers at the magmatic-hydrothermal transition. By contrast, the upper photo rather looks like the base of a polyphase sill that has experienced fractional crystallization. The dark fragment in the lower photo looks like a mafic xenolith. Please note that calcic-sodic alteration is typically found at the root zones of hydrothermal porphyry systems. Both observations imply that you are looking at the base of an igneous complex. Cheers Daniel

Dear Ahmad,

it's perhaps happened as a result of high deformation by the weather?

Dear Mr. Rabiee,

before entering in a wild speculation, I would like to raise some questions as to the mineralogical/ chemical composition and the geological setting, let´s be more precise: What is the hanging and footwall rocks like and how is the contact ? If I had no information at all, my first impression would be that of metabasic igneous rock with felsic mobilizates. But this is only a remote-controlled diagnosis Sincerely yours

Harald G. Dill

Dear all

First of all, I would like to thank you for your consideration.

Dear Professor Dill

Based on geological field constraints, the spatial position is most likely close to the roof of the mineralized stock since the overburden volcanic country rocks are seen only at several ten meters away from the outcrop and on the top the stock as well. unfortunately I do not have any evidence from the footwall and at the moment the mineralological differences between dark and light phases, though I understand that would be crucial criteria.

as Dr. Muller has pointed out, the fractional crystallization could be a possible explanation but since I am not sure if it is a thick sill (?), then I need to consider a long-term episodic conditions for magma crystallization which is unlikely for a porphyry stock emplacement level with commonly a high cooling rate.

A felsic mobilization is an interesting suggestion but a little weird due to the presence of nice layering with good boundaries and also the time and temprature that it needs for this mobilization.

I shared the picture with the intrusive xenolith deliberately to show you that how it has perturbed the layering. To assure you that the layered rock can not be crystallized-vitrified well-bedded tuff which it appears to be at the first glance. so it is not a bomb fragment! Nevertheless I still don't know either the fragment was pre-layering or even a cylindrical dyke (!).

Please let me know of your suggestions

Best Regards

Ahmad

I am agreed with the Dr. Dill, that "without knowing the mineralogical/ chemical composition and the geological setting" all are the blind guess.

Dear Mr. Rabiee:

Even after another look at the images and your information disclosed to the audience I still consider the database rather scanty and the spectrum of possible explanations is like one equation with several unknowns. The xenolith has not been impacted into a layered or bedded material. The layering is dragged downward on the left-hand side and dragged upward on the right-hand side. Whatever type of rock may be involved in this process there is a movement of this central block , most likely by some shearing. I would not like to go any further with my interpretation and start poking around in the fog of a lot of unknowns.

Kind regards

H.G.Dill

Only in the simplest of cases can one determine origins from a couple of photos taken in the field - especially in igneous and metamorphic terrains. One needs to examine the "enigmatites" directly in the field and even then may not arrive at more than speculation. There appear to be two inclusions - one light-colored and one dark - with circular cross-sections in the bottom photo that are curious but say something about the temperature regime within the enclosing rocks since the inclusions appear unmelted although to me the light-colored inclusion looks like it possibly has undergone some alteration. This, of course, is speculation on my part.

it is good question indeed

'Layering' and a 'prevalent orientation of mineral grains' (should not be called foliation, which applies to metamorphic rocks and the development of pervasive fabric only) are two very different things. If you want to understand the mechanics of grain settling leading to layreing, you might start with a paper that I co-authored. It's not the easiest read, but we make a detailed discussion of formation of meso- and adcumulates in a very simple system: basalt + olvine. Here is a link: https://rdcu.be/80qB.

Let me explain that cumulates are the product of layreing in magma chambers and potentially sills, though there is a bit more complexity into that, like in-situ crystallization of melt 'trapped' between cumulate grains. Layering due to crystal settling in a magma chamber or a sill and development of prevalent grains orientation could be coupled (or rather be active at different times ion the same magma body) and produce the most complex textures.

Geology is great! If all of us were there standing before the outrop we still wouldn't know, but all of us, that is to say, each of us, would have our own definite opinion.

Dwight Hoxie

Dear Dwight

and I really appreciate all of them because I deeply believe that there is at least a piece of answer in each opinion.

Here I started the challenge from the field evidences! Despite the fact that the field observations are the less expensive obtainable information but those could be invaluable. I am sorry that at the moment I do not have more details such as microscopic studies but I would provide more details as soon as possible.

Thank you all