10.6084/m9.figshare.3453929.v1
Kari M. Cooper
Kari M.
Cooper
Timescales of crustal magma reservoir processes: insights from U-series crystal ages
Geological Society of London
2016
data
crustal magma reservoirs control
accessory phases
Th
crustal magma reservoir processes
accessory phases show
crystals predate magmatic activity
Geology
2016-06-21 11:46:36
Dataset
https://geolsoc.figshare.com/articles/dataset/Timescales_of_crustal_magma_reservoir_processes_insights_from_U-series_crystal_ages/3453929
<p>The dynamic processes operating within crustal magma reservoirs control many aspects of the chemical composition of erupted
magmas, and crystals in volcanic rocks provide a temporally constrained archive of these changing environments. In this review,
I compile <sup>238</sup>U–<sup>230</sup>Th ages of accessory phases and <sup>238</sup>U–<sup>230</sup>Th–<sup>226</sup>Ra ages of bulk mineral separates of major phases. These data document that crystals in individual samples can have ages spanning
most of the history of a volcanic centre. Age populations for accessory phases show protracted pre-eruptive crystal residence
times but few crystals predate magmatic activity at a given centre. These data have been interpreted in the context of residence
times of the host magmas or timescales of the storage of crystals within a largely crystalline portion of the reservoir system.
In contrast, less than half of the bulk separate <sup>238</sup>U–<sup>230</sup>Th–<sup>226</sup>Ra ages for major phases are more than 10 kyr older than the eruption. Many of these apparently conflicting observations of
ages of major and accessory phases can be reconciled within the context of a model where a crystal mush was remobilized during
processes leading to eruption. Overall, the compiled data show that crystals contain rich archives of magmatic processes in
crustal reservoirs, especially when combined with other crystal-scale geochemical data.
</p>