AN: T71E-11TI: The Nature of Paleogene Magmatism Along the ACCRETE CorridorAU: A. K. SinhaEM: searches@vtvm1.cc.vt.eduAU: J. ThomasAF: Dept. of Geological Sciences, Virginia Polytechnic Institute \& State    Univ., Blacksburg, VA 24061, USAAU: M. L. CrawfordAU: W.A. CrawfordAF: Dept. of Geology, Bryn Mawr College, Bryn Mawr, PA    19010AU: J. BeardAF: Virginia Museum of Natural History, 1001 Douglas Ave., Martinsville,    VA 24112AB:     Along the ACCRETE corridor, two major plutons, Quottoon     and Ponder, provide information on the nature of the source     region, as well as the tectonothermal history of the area.     Geochemical and field observations for the Quottoon pluton     (emplaced along the Coast shear zone) suggest that a     significant mappable chemical and structural variation exists     across strike. All major oxides show markedly different     contents between the western (felsic) and eastern (mafic)     regions of the pluton, indicating the high probability that the     Quottoon pluton is a ămagmatic complexä composed of at     least two magmas. Our geochemical interpretation supports     field observations for differences in structural fabric     observed across the complex. Published variations in age     (51 to 60 m.y) and initial isotope ratios most likely reflect     episodes of magmatism where new batches of magma were     localized into a conduit along the Coast shear zone.     Additionally, variations in isotope ratios are markedly     correlated with Mg\#, i.e., the more mafic rocks (eastern     facies) are more contaminated.        In contrast, the Ponder pluton shows a well developed     normal zonation (inward enrichment of $SiO_{2}$) and,     following the models of Hutchison (1982) and Sisson     (1985), we suggest that a single liquid can form the different     igneous facies of the pluton.        Attempts to relate potential differences in source regions for     the two Paleogene plutons is made difficult, as all major     elements show similar evolutionary paths. Preliminary Pb     isotope data across the ACCRETE transect show no isotopic     discontinuities east of the Coast shear zone, suggesting a     similar source region for the two major magmatic     complexes.    SC: TDE: 8110DE: 1040MN: Fall Meeting 1996