Page 58 - Caldera Volcanism Analysis, Modelling and Response

Residence Times of Silicic Magmas Associated with Calderas 33

Magma production rate km 3 y 1 (vol/ residence time) 1.3–6 10 2

Thermal modelling 100–200 ky [B&B03] radioactive clocks (e.g., U–Th–Pb, Rb–Sr). San, sanidine, Bt, ´

Magma residence time a 400 ky to Up Min.80 ky, max.900 ky [B07b] 360 ky 250 ky to Up

[B07b] [B07b] [LB01] [SB01] [SB01] [B07b]

Tuff. age Zrc=28.3370.15 Ma Zrc=28.4170.10 Ma Zrc=27.5270.09 Ma Zrc=28.47670.029 Ma Tit=28.39570.049 Ma Zrc=28.3170.30 Ma

Canyon U--Pb

Fish biotite, Zrc, zircon, Tit, titanite, Felds, feldspars. Data sources: [B&B03], Bachmann and Bergantz (2003), [B07b], Bachmann et al. (2007b); [D03], Daze et al. (2003); [L00b], Lipman (2000b); [LB01], Lanphere and Baadsgaard (2001), [SB01], Schmitz and Bowring (2001). The 40 Ar/ 39 Ar data shown for Bac
the age
for and Bt=27.447 0.16 Ma [LB01]
rates Rb--Sr isochron Felds
process [LB01] location.

and (eruption) [B07b] [B07b] [D03] [B07b] [B07b] [B07b] [B07b] [B07b] Note: Vol, Volume in dense rock equivalent. a this is taken as the difference between the eruption ages and those of other Valley Fun
times Bt=27.5770.18 Ma the for

residence 40 Ar/ 39 Ar age San=27.9370.09 Ma Bt=28.2570.10 Ma Bt=28.1370.24 Ma San=28.0470.09 Ma Plag=28.3170.11 Ma Hbl=28.2370.12 Ma Bt=28.2570.09 Ma and San=28.0770.09 Ma are Tuff

data, San Canyon

age (km 3 ) [B07b] [L00b] [B07b] Fish
Volume, Vol 200 5000 o1 Flow the of

8 Garita system Peak Dacite Canyon Tuff Creek Dacite zircon of
Table La Pagosa Fish Nutras those