Welcome to the Rock Tumbling Hobby Forum where we share a love of rocks and a sense of community as enduring as the stones we polish.
The RTH Forum of www.RockTumbling.com is an Amazon Associate site and we earn money from
qualifying purchases you make after clicking on our links such as this
Rock Tumbling Supplies on Amazon
link for instance, or any of our various product ads and banners. By clicking our links every time you begin your Amazon shopping
experience, you are generating a bit of revenue for the forum which helps us cover our expenses. Thank you for your support!
If you cannot see Amazon ad banners directly below this text, please whitelist this site in your ad blocker(s). The ads below have been hand-selected for relevant content, and your patronage directly benefits this forum community, thanks!
Figure 3. Distribution of ca. 11–9 Ma high-K volcanic rocks in the Sierra Nevada and in the adjacent Walker Lane belt east of the Sierra Nevada range crest (revised from Pluhar et al., 2009); stratigraphy is described in Figure 4.
We propose herein that two distinct paleochannels (Cataract and Stanislaus) merged downstream into one (Cataract). Basal Stanislaus Group paleochannel fill consists of Table Mountain Latite (TML) lava, which erupted from fissures and was ponded to ~400 m thickness in the Sierra Crest graben-vent system (Fig. 2B).
Several TML lavas flowed down the Cataract paleochannel 130 km to Knight’s Ferry, shown at the westernmost edge of this figure, but the lavas that escaped down the paleochannel are <80 m thick (Gorny et al., 2009; Busby et al., 2013a).
The Eureka Valley Tuff includes trachydacite welded ignimbrites (Fig. 4) erupted from the Little Walker caldera (shown here); it is more extensive than the TML lavas because of the much greater mobility of pumice-rich pyroclastic flows (area shaded dark gray).
Along the Sierra Nevada crest (brown dashed line) and east of it, the distribution of high-K rocks was largely controlled by grabens, rather than paleochannels.
Inset: CR—Coast Ranges; GV—Great Valley; KM—Klamath Mountains; SCM—southern Cascade Mountains; SN—Sierra Nevada. Modified from King et al. (2007), Pluhar et al. (2009), and Busby et al. (2013a).
This space is for temporary chat only and all posts drop off automatically and are not saved.
Members with real questions or comments that need an actual response, please post on the main forum - not here! Casual PG-13 posts only, no politics or religion please!
Mel: Potatoes have lots of eyes but no one thinks they're anything special....
Mar 22, 2024 21:14:51 GMT -5
Welcome to the Rock Tumbling Hobby Forum where we share a love of rocks and a sense of community as enduring as the stones we polish.
The RTH Forum of www.RockTumbling.com is an Amazon Associate site and we earn money from
qualifying purchases you make after clicking on our links such as this
Rock Tumbling Supplies on Amazon
link for instance, or any of our various product ads and banners. By clicking our links every time you begin your Amazon shopping
experience, you are generating a bit of revenue for the forum which helps us cover our expenses. Thank you for your support!