  This is a study of abundances of the elements He, C, N, O, Ne, Mg, Si, S, Ar,
Ca, and Fe in solar energetic particles (SEPs) in the 2 - 15 MeV amu-1 region
measured on the Wind spacecraft during 54 large SEP events occurring between
November 1994 and June 2012. The origin of most of the temporal and spatial
variations in abundances of the heavier elements lies in rigidity-dependent
scattering during transport of the particles away from the site of acceleration
at shock waves driven out from the Sun by coronal mass ejections (CMEs).
Variation in the abundance of Fe is correlated with the Fe spectral index, as
expected from scattering theory but not previously noted. Clustering of Fe
abundances during the "reservoir" period, late in SEP events, is also newly
reported. Transport-induced enhancements in one region are balanced by
depletions in another, thus, averaging over these variations produces SEP
abundances that are energy independent, confirms previous SEP abundances in
this energy region, and provides a credible measure of element abundances in
the solar corona. These SEP-determined coronal abundances differ from those in
the solar photosphere by a well-known function that depends upon the first
ionization potential (FIP) or ionization time of the element.
