I am dealing with MMEs hosted by tonalites.Petrographic and geochemical characters supports magma mixing origin for the MMEs. Sr-Nd-Hf isotopic analysis for both host rock and associated MMEs shows mantle source.
For magma maxing mechanism ,we should have crustal and mantle source but,in my case the isotopic data shows same parental source ,which is mantle.
Hi Mubasir,
Who did say that you need mantle- and crustal-derived melts to have mixing? You can have such process between two (or more) melts derived from the same type of sources.
There is a weal6of scientific articles dealing with this.
MME are often associated to imperfect mixing, i.e. magma mingling.
Cheers,
Michele
Hi Michele,
There are many articels about magma mixing origin of MMEs. (Vernon, 1983, 1991; Dorais et al., 1990; Castro et al., 1990; Barbarin and Didier, 1992) mentioned that MMEs commonly interpreted as products of mixing and mingling of mantle- and crust-derived magmas.Magma mixing/mingling is defined as bringing together two initiallydistinct magmas to achieve an equilibrium approach along the spectrumfrom mingling to hybridization (Barbarin, 2005).In the light of these authers' articles ,there should have distict crustal and mantle source magma ,if we deem magma mixing origin for the MMEs.
Conversely,Cognate origin MMEs have same parental magma source (Barbarin, 2005; Donaire et al.,2005).@Michele
Yes Mubasir. You are dealing with articles 30-40 years old. I was only emphasising that the two magma can have the same type of sources.
Magma mingling does not require equilibrium, as you write. You can suggest crustal and mantle end-members only in presence of strong isotopic disequilibrium.
Again: no reason to invoke automatically two distinct sources for MME. Check literature on MME from Elba and Montecristo Islands (Tuscan archipelago, Italy) or from Sarrabus (Sardinia, Italy).
The MME presence is much more complex and cannot be categorised so simply. Give a look on the abundant literature, for example checking the articles of Diego Perugini and Giampiero Poli and their "strange attractors".
Cheers,
Michele
Thank you very much for the explaination and recommendations.I will go through it.
Regards;@Michele
I have also encountered magma mixing of quartz trachyte and basaltic magmas often forming contemporaneous intrusions or flows in the Deccan Volcanic Province. Both the melts are of mantle origin. My observation is that such intrusions/flows form in the later stages of eruption, associated with faulting and invariablly are associated with very high gravity anomalies. The high gravity anomalies indicae an upwarp of the mantle with associated decompression melting. I have attributed the development of the basic melt from the mantle, while the trachytic melt develops by differentiation or decomression melting from the underplating basalt.
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