Kindly check pages 217-234 in the book titled: PRINCIPLES OF ISOTOPE GEOLOGY by Gunter Faure, Publisher: John Wiley and Sons. You will definitely find your answer there. Thanks

Thank you. But I have not access to this reference at now. Is there any other similar text simply has described this?

This is a complete source:

http://earthref.org/GERM/

So interesting site!

Thank you Albert.

If you have acces to Hugh Rollingson "Using Geochemical Data" they have a lot of related material or you can check "Geochemistry by Williams and White" (I think it online somewere".

but as a fast answer MORB (Depleted Mantle) has values up to +5 eNd or 0.51235-0.512245 that can be the same in some Island Arcs without sediment or crustal contaminations and even the same in some SSZ basalts...

Actually I try to check the same for my PhD but the only conclusion that can have is that Subduction related basalts can have in some cases even OIB signatures so you must check endmember as MORB, OIB, Continental Crust or Sediments (nagative eNd values) and then evaluate the participation of these in your rocks, because if you try to define a "common Island Arc Basalt" or "SSZ basalt" you probably go crazy...

Thank you Pablo. I should look up in the geochemistry by Williams and White too. May I ask for your publications if considered this?

Actually Im in the co-autors corrections of a paper about subduction related volcanism of the Upper Jurassic in the Andean Margin, and I consider 3 different isotopic sources (Depleted Mantle-Pz Crust-OIB mantle) to explain the across arc (arc to back-arc) variations. Lamentably this is gona be my first "first autor" publication (im still PhD candidate) but when it ready I uploaded

and...sorry for my poor English jejeje

Hope you luck in your research works. I am PhD candidate too!

Some of my samples show a composition between OIB and MORB and this made me confused to interpret this.

What do you mean by "Pz Crust"?

Could you please plot your data in a 143Nd/144Nd versus 87Sr/86Sr correlation diagram and delineate the fields for your samples according to their geologic settings and post it. I would advise. However, most rocks from Island arcs seemed to be contaminated with Nd and Sr presumably from crustal rocks of sialic composition and therefore display compositions that lie between MORB and Crustal rocks.

Pz Crust mean paleozoic crust, but that was refered to the basement, y use paleozoic because is the main basement of Chilean Margin...you know...0.5 Gyr of subduction can eat almost everithing :S...but if you work in other environments probably you have some archean basement...

You have some Pb isotopes? they are very usefull to determine the participation of OIB sources (HIMU sources).

As Mr Uriah Lar says, the best exercise is to plot your data and the data of the posible end members (Crustal rocks, Sediments, OIB, Lithospheric mantle, MORB) and if they plot in the line of two of them probably they are the surce, if not you need an extra source.

What is the topic of your research?

Ok thanks Pablo. I will have only the Sm - Nd data but I'm not sure it is enough!

Pb and Sr isotopes are needed to conclude!

My rocks (basic rocks from ophiolite) are not older as Paleozoic nor Archean. I guess they can be classified in Meso- and Cenozoic ages.