See Figure DR5 (from the data repository) from Blum and Pecha 2014-this is an excellent, up to date summary map, although there are smaller plutons, igneous suites, and terranes that are missing from this map (they are too small to effectively show on a continental scale map).

ftp://rock.geosociety.org/pub/reposit/2014/2014213.pdf

Zircon fertility is much trickier. Moecher and Samson (http://www.sciencedirect.com/science/article/pii/S0012821X06003396) is a good start, but zircon fertility can change abruptly across small spatial or temporal spans.

Hello Matt,

Thanks for the info. I am glad we came to interact-- I am working with Julian and Andrea this summer in Austin!

I will have a second look at Blum and Pecha...

AS for the second part, I understand that zircon fertility is complex and nearly impossible to quantify for large spatial scales. However we want to try to quantify sediment mixing using DZ, which requires some consideration of fertility. So what is your opinion on this idea: apply some estimates of fertility to large geographic areas based on terrane age, area and tectonic framework using data published by Dickinson (2008). Could this give first-order approximations that would be better than no consideration in a mixing model?  Or do you feel this might be a waste of time/wrong approach?

Thanks

C

Excellent topic! Lets continue this conversation offline. shoot me an email at [email protected] and we can discuss.

Maybe this is what the Moecher paper was in part getting at, but If you have Zr concentrations from representative bulk rock compositions, and you also know something about the area/volume extent of each unit, then that should give you a rough approximation of zircon fertility in an area / catchment. Obviously this requires a reasonable geochemistry database for the region of interest (USGS has a fairly extensive dataset for the US), and I imagine there might also be some issues with this kind of approach being skewed by small volume units that have lots of zircon and vice versa.