Since the Seventies I have been gathering datasets to supplement and evaluate a variety of plate tectonic models. In
1978 Tim Cross and I published a paper
on the tectonic evolution of the western United States from the Late Cretaceous to the Present. Part of that paper was a generalization
in the form of contours indicating the onset and extinction of magmatism in this period and our largely qualitative interpretation.
The compilation as such was a stack of Hollerith
cards that were fed into a plotter from which we produced the contour maps. Subsequently the US Geological Survey produced
that overlaps significantly with our dataset, so I never worried about making our compilation portable. A year later
(1979) I published a paper which expanded the database into coastal California
and drawn from my USC dissertation; some of the data utilized in that paper were derived from an unpublished dissertation
from the other Los Angeles university and which is not included in the USGS compilation; it's on my to-do list to make that
dataset available eventually.
In 1981 I published a couple of related papers, on the hotspots
of the Nazca and Pacific plates and the interaction of their traces with the sub-Andean subduction zone
beneath South America. In 1984 I updated and extended reconstruction parameters to earlier dates and expanded the compilation
of isotopic ages of igneous rocks from the Andes. In more recent years I have gone to the effort of expanding the database
and producing kml formatted files for viewing in Google Earth. The actual spreadsheet files are now stored in Google Drive
(or its latest incarnation) and linked to from this page and researchgate.net
. (Incidentally, the sub-Andean subduction paper is the most cited of all my published papers; it incorporates several firsts:
Nazca-South America plate reconstructions, hotspot trace interaction with the subduction zone, and comparison of igneous age
dates with reconstructed trace interaction.)
The latest South American radiometric date compilation
can be found here
. There are nearly 20,000 dates from igneous rocks of the Andes and adjacent areas included and over 19.000 dates on non-igneous
rocks. In both cases, there is a kind of inflation of U-Pb dates with the new technology that allows for rapid dating of many
zircons in a single analytical cycle, including dating of different zones of the same crystal. I'm trying to figure out how
to deal with this avalanche of data, as I don't want to simply abstract the results; I welcome alternative suggestions. In
a few cases I am missing reference citations and am attempting to catch-up. Assistance would always be welcome.
intend adding other datasets and their links here, too.