U–Pb geochronology of zircon and monazite from Mesoproterozoic granitic gneisses of the northern Blue Ridge, Virginia and Maryland, USA

Laurentia-Baltica-Amazonia relations during Rodinia assembly

“…Based on detailed geochemical and geochronological studies within the Blue Ridge inlier in the southern Appalachians (Aleinikoff et al, 2000;Tollo et al, 2006;Tollo et al, 2004), three magmatic stages of a (AMCG) emplacement occurred at ~1185-1145 Ma, ~1120-1110 Ma and ~1080-1030 Ma.…”

Zircon U-Pb geochronology of the Ottawan Orogeny, Adirondack Highlands, New York: regional and tectonic implications

“…Recently Aleinikoff et al (2000) have reported U-Pb zircon ages for granitic gneisses from the Blue Ridge province of Virginia and Maryland. These bear a striking resemblance to Adirondack AMCG, Hawkeye, and LMG suites discussed in this paper.…”

“…In this regard, these rocks are situated in relatively close proximity to the subsurface termination of the MCR in eastern Ohio. Most significantly, the investigation of Aleinikoff et al (2000) has revealed the presence of large volumes of LMG-equivalent granite, leucogranite, and quartz-plagioclase rock, all dated at 1075-1055 Ma, crosscutting D1 fabrics, and exhibiting syn-to post-orogenic textures of their own. Monazite ages of 1070-1035 Ma indicate that, as in the Adirondacks, intrusion of this younger granitic suite took place while metamorphic temperatures were still high.…”

“…This is also true in the Adirondacks where, as previously discussed, most LMG occurrences are involved in open folding. Aleinikoff et al (2000) point out that the limited U-Pb dating in the New York and New Jersey Highlands makes it difficult to correlate continuously from the Blue Ridge to the Adirondacks. However, the deformed Storm King granite of the Hudson Highlands yields an age of ca 1172 Ma (Aleinikoff, Ratcliffe, personal communication) which corresponds to late Elzevirian and early AMCG events within the Adirondacks (Wasteneys et al, 1999).…”

Evolution of migmatitic granulite complexes: Implications from Lapland Granulite Belt, Part II: Isotopic dating

“…Recently, especially monazite data have proven useful in determining metamorphic and/or deformation phases (Bruguier et al, 1999;Crowley & Parrish, 1999, Foster et al, 2000, thermal history of metamorphic complexes (Aleinikoff et al, 2000;Hawkins & Bowring, 1999) or their geodynamic regime (Vavra & Schaltegger, 1999). One reason for the increased utility of monazite in geochronology of high-grade rocks is that monazite is apparently not reset and annealed as easily as earlier thought and may resist fluids even more efficiently than zircon (Parrish & Whitehouse, 1999;Schaltegger et al, 1999;Vavra & Schaltegger, 1999).…”