TRENDS DURING 650 THOUSAND YEARS OF CAMP MAGMATISM

New precise chronological data (Blackburn et al., 2013) is now available for seven eastern North American CAMP events located between the Fundy, Nova Scotia and Deep River, North Carolina basins including a Culpeper basin, two Newark basin, and two Gettysburg basin events. Existing and new geochemical data (Merle et al., 2014) together with a recently developed geothermometer (Herzberg and Asimow, 2008) can be utilized to determine time and space constrained geochemical trends. Samples of North Mountain Basalt from the Fundy Basin are 650 thousand years older than samples of Butner diabase from the Deep River Basin to the south with intermediate dates for the five included sample groups. Four trends can be discerned: 1. The younger magmas to the south contained a higher continental crustal component than the northern magmas on the basis of a consistent southern increase in La/Nb. 2. The source of the younger magmas underwent a higher degree of melting than the older magmas on the basis of a gradual southern decrease in Ti and REEs. 3. The mantle potential temperature calculated for the younger magmas was higher than the older northern magmas. 4. The younger magmas melted at deeper levels than the older magmas on the basis of decreased silica and increased iron content toward the south. The increased depth with time agrees with interpretations made by Salters et al. (2003) and is consistent with passive models but is inconsistent with plume models pertaining to the origin of CAMP. The north to south deepening of melting can be extended as far south as Georgia/Alabama although the southern increase in the degree of partial melting is reversed in the Carolina and decreases toward Georgia/Alabama on the basis of data published by Ragland et al. (2003).