1976年1月1日 · We use field mapping, outcrop scale scanline transects, and petrographic analyses to characterize fault rocks, alteration, and veins in the well-exposed 22.9 Ma Lake City caldera fossil...

Geologic map of the Lake City Caldera area, western San Juan Mountains, southwestern Colorado January 1, 1976 View Plate

Part I. 18O/16O analyses were made on 355 samples in and around the 11 by 14 km Lake City caldera, which formed 23 m.y. ago in response to the eruption of the rhyolitic Sunshine Peak Tuff. All of the major lithologies and hydrothermal alteration facies were analyzed, and a detailed δ18O map was made of the caldera and its surroundings.

The Lake City caldera, located within the older Uncompahgre caldera, formed about 22.5 m.y. ago in response to eruption of the Sunshine Peak Tuff. 16 p. The sequence of mid-Cenozoic volcanic events in the western San Juan Mountains is closely …

Rocks from the 23 Ma Lake City caldera show diverse chemical affinities attesting to a complex magmatic system beneath the caldera. Field and geochemical data from ignimbrites and intrusions constrain magma storage and magma interactions during the formation of the caldera.

Geologic map of the Lake City Caldera area, western San Juan Mountains, southwestern Colorado IMAP 962 By: Peter W. Lipman https://doi.org/10.3133/i962

1973年1月1日 · Intrusions of related rock invaded the eastern and northern margins of the Lake City caldera late in its cycle of development, and a larger pluton resurgently domed the core of the caldera...

The Lake City caldera, formed during the ca. 23 Ma SPT super-eruption, is the youngest of the 25 Tertiary calderas in the Southern Rocky Mountain Volcanic Field (SRMVF; Lipman, 1976;Steven and ...

Twenty-five new Ar/Ar ages from volcanic rocks and veins in the western San Juan Mountains clarify relationships between volcanism and mineralization in this classic area. Five calc-alkaline ash-flow… .....................................................................

Rocks of the 23.1‐m.y.‐old Lake City caldera consist of the compositionally zoned Sunshine Peak Tuff, postcollapse intracaldera lava flows, and resurgent quartz syenite intrusions.