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Hi Paula, I am very appreciative of your systematic response. Cool, and I think I will just keep practicing with what is available for me now. Will ask for help if more to come. Thanks~

Hi Paula, Thanks a lot for telling me that.
Also, I am also thinking if somewhere has the 1.9 version tutorial for this exercise: 
Melts camp exercises (https://magmasource.caltech.edu/alphamelts/1/exercises-for-melts.htm).
I tested using 1.9 and it does not completely match.

The last question is that I am trying to find the equilibrate solid residual for a melt composition I have (based on fine-grain diabase). According to other literature and my trace element plots, the source rocks should be in spinel-peridotite facies. Thus, if I have P, T and oxygen fugacity, plus the melt composition, how can I use them to infer the solid residual so that I can further add to the melt to get the source composition? After getting the source composition I can then test if it is stable under spinel-peridotite facies. Or is it much practical to do isentropic melting of mantle rocks until I found the melt composition similar to the melt I have?

Any suggestions will be greatly appreciated!

Qian

Hi Paul,

Thank you so much for your prompt reply. You solved my puzzle~ Cannot believe I did not think of it as I found the temperatures of all my calculations are all too high~ Will do that for sure~ Thanks again~


Qian

Hi all,

I am new for Melts and have met a basic problem after installing the alphamelts_1-9 on Mac.

I first tried to reproduce the example for isobaric fractionation of Morb.melts given by Paula at https://magmasource.caltech.edu/forum/index.php/topic,840.msg1195.html#msg1195.
However, the liquidus temperature calculated by my software at the beginning was too high at 1473.15 K, which is about 250 higher than the one in that tutorial. I noticed previous posts about "liquidus temperature high mg magma", while my sample is just a reference case here and should be the same results as the tutorial.

Here are my terminal command lines: run_alphamelts.command -f frac_xtal_env.txt
Outputs:
ALPHAMELTS_MINP 1
ALPHAMELTS_MINT 500
ALPHAMELTS_MAXP 30000
ALPHAMELTS_VERSION MELTS
ALPHAMELTS_FRACTIONATE_SOLIDS true
ALPHAMELTS_DELTAP 0
ALPHAMELTS_MAXT 2400
ALPHAMELTS_DELTAT -1
ALPHAMELTS_MODE isobaric

The Morb.melts output is:
MELTS filename: Morb.melts
input file open
Successfully read 'title: allan et al. 1989 (see ghiorso 1997)'
Successfully read 'initial composition: sio2 48.68'
Successfully read 'initial composition: tio2 1.01'
Successfully read 'initial composition: al2o3 17.64'
Successfully read 'initial composition: fe2o3 0.89'
Successfully read 'initial composition: cr2o3 0.03'
Successfully read 'initial composition: feo 7.59'
Successfully read 'initial composition: mgo 9.10'
Successfully read 'initial composition: cao 12.45'
Successfully read 'initial composition: na2o 2.65'
Successfully read 'initial composition: k2o 0.03'
Successfully read 'initial composition: p2o5 0.08'
Successfully read 'initial composition: h2o 0.20'
Successfully read 'initial temperature: 1200.00'
Successfully read 'initial pressure: 500.00'
Successfully read 'log fo2 path: none'
Successfully read 'mode: fractionate solids'

I then selected the Single (batch) calculation, and the output for this is:
Your choice: 3
Superliquidus (1) or subsolidus (0) initial guess ? 1
...Adding the solid phase feldspar to the assemblage.
...Adding the solid phase olivine to the assemblage.
Initial alphaMELTS calculation at: P 500.000000, T 1473.150000
liquid: 82.239 g 49.00 1.23 15.85 1.08 0.04 8.49 8.71 12.39 2.83 0.04 0.10 0.24
Activity of H2O = 0.0266901  Melt fraction = 0.819522
olivine: 4.275507 g, composition (Ca0.01Mg0.85Fe''0.15Mn0.00Co0.00Ni0.00)2SiO4
feldspar: 13.835487 g, composition K0.00Na0.21Ca0.79Al1.79Si2.21O8

I tried to remove the software and reinstalled it, while does not help. Any helps will be greatly appreciated.

Qian