In dependent origination, ignorance (avijja) is the cause for sankhara:
Quoted from MN 9: http://www.accesstoinsight.org/tipitaka ... .ntbb.html" onclick="window.open(this.href);return false;62. "And what are formations, what is the origin of formations, what is the cessation of formations, what is the way leading to the cessation of formations? There are these three kinds of formations: the bodily formation, the verbal formation, the mental formation. With the arising of ignorance there is the arising of formations. With the cessation of ignorance there is the cessation of formations. The way leading to the cessation of formations is just this Noble Eightfold Path; that is, right view... right concentration.
But in describing the aggregates (khandhas), contact (phassa) is given as the cause of sankhara.
Quoted from MN 109: http://onlinedhamma.net/nanda/AccessToI ... .than.html" onclick="window.open(this.href);return false;"Monk, the four great existents (earth, water, fire, & wind) are the cause, the four great existents the condition, for the delineation of the aggregate of form. Contact is the cause, contact the condition, for the delineation of the aggregate of feeling. Contact is the cause, contact the condition, for the delineation of the aggregate of perception. Contact is the cause, contact the condition, for the delineation of the aggregate of fabrications. Name-&-form is the cause, name-&-form the condition, for the delineation of the aggregate of consciousness."
I'm a little confused on the distinction here.
From what I understand, in the three life model of dependent origination, sankhara is referring to the kammic formations of the previous life, which condition the arising of consciousness (vinnana) in the new life. But I also know that some do not use the three life model of dependent origination. So how do you understand sankhara in terms of d.o.?
Also, in d.o., contact comes later in the sequence, after sankhara and therefore dependent upon sankhara, not the other way around as described in the explanation of the aggregates above.
I guess I'm just confused -- if the causes are different and the meanings are different, why use the same word in both spots?