Hi all,

Apologies for the delay in putting the new ds6 dataset up on the web. It 
has turned out to be more work than expected to sort out aspects arising 
from it, and appropriate a-x files are still under development.

For anyone interested, the latest Holland and Powell 2011 dataset (DS61) 
is now (finally) up on the THERMOCALC website. Go to the following page 
and hit the DS6 icon on the left

http://www.metamorph.geo.uni-mainz.de/thermocalc/index.html

Please note that this dataset will only work with the version of 
THERMOCALC that is included in the download.

The new dataset can only be used in a limited capacity at the moment as 
the existing (ds55) era a-x models are inappropriate for use with the 
new dataset. See below for more details.

The transition from tc-ds55.txt to tc-ds61.txt is non-trivial for all 
concerned, including you the user. Much has changed. For those of you 
who are mid-project it is not wise to think of jumping to the new 
dataset unless there is something specifically in the new dataset that 
will dramatically improve your modelling. The dataset, tc-ds55.txt, and 
accompanying axfiles have been widely used and are considered to be 
quite stable, as well as being good at reliably modelling the majority 
of rocks. So keeping on using tc-ds55.txt is your best plan for projects 
already started.

For use with the new dataset, many of the existing activity-composition 
relationship codings in axfiles will need to be modified, mainly because 
the underlying assumptions in dataset generation have changed 
substantially in the intervening 8 years between tc-ds55.txt and 
tc-ds61.txt. The existing ds55-generation axfiles should NOT be used 
with tc-ds61.txt as this will in most cases result in erroneous results 
(e.g. with biotite, amphibole, melt). There are other codings (e.g. 
chlorite, cordierite) that we are taking this opportunity to upgrade 
because the current ones, for various reasons, are obsolete. Our aim, of 
course, is to make these new axfiles as stable and reliable as the old 
ones. Clearly this is a big job - one that we are working hard on - so 
please be patient and await their release on the website. Of course, in 
the mean time you can use tc336 for calculations on end-members with 
tc-ds61.txt (e.g. with modes 0 and 3) to look at the new dataset. (This 
version of THERMOCALC (tc336) is fully backwards compatible).

Cheers,

Richard



-- 
Richard White
Metamorphic Geology
Institute of Geoscience
Becherweg 21
University of Mainz
Mainz D-55099
Germany

Fax:  +49 6131 39 23863
Phone: +49 6131 39 24781

Web: http://www.metamorph.geo.uni-mainz.de/englisch/e_index.html
THERMOCALC web: http://www.metamorph.geo.uni-mainz.de/thermocalc/index.html