Abundances of major, minor, and trace elements were determined in the whole rock and mineral separates of the two distinct lithologies present in the Antarctic achondrite Elephant Moraine A (EETA) 79001 via sequential instrumental (INAA) and radiochemical neutron activation analysis (RNAA). Additional chalcophile, siderophile, and volatile trace elements are reported for the shergottities ALHA 77005, Shergotty, and Zagami. The rare earth element (REE) abundances of each of the lithologies of EETA 79001 (A and B) exhibit chondritic normalized patterns similar to ALHA 77005. The close relationship of the Antactic shergottites indicates that ALHA 77005 is a residual source produced by incongruent melting of a source similar in bulk composition to EETA 79001A and that EETA 79001B and the interstitial phases in EETA 79001A are the melts produced by such melting episodes. Incorporating previous isotopic studies and our chemical data we suggest that either fractionation of or contamination by feldspar could account for the different shergottite sources. The large ion lithophile (LIL) trace element abundances of the shergottites require variable but extensive degrees of nonmodal melting of isotopically constrained parent sources. The extreme extent of such melting is hypothesized to be represented by ALHA 77005 as a residual composition. Derivation of a pre-1.3 AE(109 yr) fractionation sequence is suggested in which ol, ol+opx, opx+cpx, and opx+cpx+plag sequentially produce residual liquids capable of accounting or the precursor sources for the SNC metorites. On the basis of chemical, isotopic, and petrologic considerations we conclude that the SNC sources are consistent with their derivation by extensive fractionation of a primitive magma intially produced from a source having chondritic refractory LIL trace element abundances, FE' (Fe/Fe+Mg atomic)≲0.3, and a mineralogy primarily of ol and pyx. Our model-dependent deductions suggest that this magma could be derived without plagioclase or garnet left in the residuum. Petrogenetic and age relationships among SNC meteorites suggest a single complex-provenance on a dynamic planet not unlike the earth. Considering that each of these meteorites possesses chemical, isotopic, and petrologic features consistent with data presently available from Mars, we conclude that a Martian origin is quite probable.