Magma accumulation rates and thermal histories of plutons of the Sierra Nevada batholith, CA

作者：Davis Jesse W^*; Coleman Drew S; Gracely John T; Gaschnig Richard; Stearns Michael

来源：Contributions to Mineralogy and Petrology, 2012, 163(3): 449-465.

DOI：10.1007/s00410-011-0683-7

• Geochronology
• Thermochronology Pluton
• Pluton emplacement
• Sierra Nevada batholith

Zircon U-Pb geochronology results indicate that the John Muir Intrusive Suite of the central Sierra Nevada batholith, California, was assembled over a period of at least 12 Ma between 96 and 84 Ma. Bulk mineral thermochronology (U-Pb zircon and titanite, Ar-40/Ar-39 hornblende and biotite) of rocks from multiple plutons comprising the Muir suite indicates rapid cooling through titanite and hornblende closure following intrusion and subsequent slow cooling through biotite closure. Assembly of intrusive suites in the Sierra Nevada and elsewhere over millions of years favors growth by incremental intrusion. Estimated long-term pluton assembly rates for the John Muir Intrusive Suite are on the order of 0.001 km(3) a(-1) which is inconsistent with the rapid magma fluxes that are necessary to form large-volume magma chambers capable of producing caldera-forming eruptions. If large shallow crustal magma chambers do not typically develop during assembly of large zoned intrusive suites, it is doubtful that the intrusive suites represent cumulates left behind following caldera-forming eruptions.

• 出版日期2012-3