Supplementary Data Files to accompany "New dimensions of Ediacaran magmatism in the southeastern New England Avalon zone, USA." (Thompson, M.D., Crowley, J.L., and Ramezani, J. 2025).

These thirteen files contain the supplementary data that accompany the publication for which the full citation is given below.
<b>Abstract</b>: High precision CA-ID-TIMS U–Pb zircon geochronology establishes 627.68 ± 0.66 Ma (2σ internal uncertainty) diorite at Rowley and associated tonalite near Topsfield, Massachusetts as the earliest arc-related magmatic rocks recognized so far in the southeastern New England Avalon zone. Granite dated at 609.10 ± 0.18 Ma on the southern extremity of this terrane in Newport, Rhode Island corresponds in age to previously dated Dedham Granite that is widespread in the vicinity of Boston, Massachusetts. Slightly younger diorite (605.48 ± 0.21 Ma) in an upfaulted block west of Boston clusters with previous dates from the Milford and Fall River granites. Westwood Granite redated at 595.17 ± 0.50 Ma proves to be co-eval with Lynn–Mattapan volcanic rocks. LA-ICP-MS age spectra from the same samples (except Westwood Granite) also show inherited components. The Ediacaran crystallization ages for the southeastern New England suite overlap LA-ICP-MS ages from numerous samples in Avalonia exposed in Nova Scotia's Cobequid and Antigonish highlands. These ages both reinforce previous comparisons between these terranes and reveal patterns of incremental intrusion like those documented for continental arc-related plutons of the western United States. Mesoproterozoic and older inherited components in both cases reflect West Avalonian origins as a series of volcanic arcs developed on metasedimentary deposits that detached from the Timanide margin of Baltica. By the time ca. <630 Ma Jeffers Group tuffs (Nova Scotia) and Topsfield Granodiorite (Massachusetts) acquired Cryogenian xenocrysts, their respective West Avalonian terranes were drifting towards collision with Ganderia, precluding Baltica provenance for ca. 680–640 Ma zircon. The source of this inheritance remains unresolved.