scholarly journals Patterns of incision and deformation on the southern flank of the Yellowstone hotspot from terraces and topography

2021 ◽  
Author(s):  
Daphnee Tuzlak ◽  
Joel Pederson ◽  
Aaron Bufe ◽  
Tammy Rittenour
Keyword(s):  
Late Quaternary ◽  
Slip Rate ◽  
Snake River Plain ◽  
Fault System ◽  
Snake River ◽  
Normal Faults ◽  
Localized Deformation ◽  
Fluvial Terraces ◽  
Yellowstone Hotspot ◽  
River Plain

Understanding the dynamics of the greater Yellowstone region requires constraints on deformation spanning million year to decadal timescales, but intermediate-scale (Quaternary) records of erosion and deformation are lacking. The Upper Snake River drainage crosses from the uplifting region that encompasses the Yellowstone Plateau into the subsiding Snake River Plain and provides an opportunity to investigate a transect across the trailing margin of the hotspot. Here, we present a new chronostratigraphy of fluvial terraces along the lower Hoback and Upper Snake Rivers and measure drainage characteristics through Alpine Canyon interpreted in the context of bedrock erodibility. We attempt to evaluate whether incision is driven by uplift of the Yellowstone system, subsidence of the Snake River Plain, or individual faults along the river’s path. The Upper Snake River in our study area is incising at roughly 0.3 m/k.y. (300 m/m.y.), which is similar to estimates from drainages at the leading eastern margin of the Yellowstone system. The pattern of terrace incision, however, is not consistent with widely hypothesized headwater uplift from the hotspot but instead is consistent with downstream baselevel fall as well as localized deformation along normal faults. Both the Astoria and Hoback faults are documented as active in the late Quaternary, and an offset terrace indicates a slip rate of 0.25−0.5 m/k.y. (250−500 m/m.y.) for the Hoback fault. Although tributary channel steepness corresponds with bedrock strength, patterns of χ across divides support baselevel fall to the west. Subsidence of the Snake River Plain may be a source of this baselevel fall, but we suggest that the closer Grand Valley fault system could be more active than previously thought.

In the Wake of the Yellowstone Hotspot

2000 ◽  
Author(s):  
Robert B. Smith ◽  
Lee J. Siegel
Keyword(s):  
National Park ◽  
Lava Flows ◽  
Snake River Plain ◽  
Snake River ◽  
Earthquake Activity ◽  
Basalt Lava ◽  
Mountain Ranges ◽  
Yellowstone Hotspot ◽  
A Chain ◽  
River Plain

Anyone who drives through southern Idaho on Interstates 84 or 15 must endure hours and hundreds of miles of monotonous scenery: the vast, flat landscape of the Snake River Plain. In many areas, sagebrush and solidified basalt lava flows extend toward distant mountain ranges, while in other places, farmers have cultivated large expanses of volcanic soil to grow Idaho’s famous potatoes. Southern Idaho’s topography was not always so dull. Mountain ranges once ran through the region. Thanks to the Yellowstone hotspot, however, the pre-existing scenery was destroyed by several dozen of the largest kind of volcanic eruption on Earth—eruptions that formed gigantic craters, known as calderas, measuring a few tens of miles wide. Some 16.5 million years ago, the hotspot was beneath the area where Oregon, Nevada, and Idaho meet. It produced its first big caldera-forming eruptions there. As the North American plate of Earth’s surface drifted southwest over the hotspot, about 100 giant eruptions punched through the drifting plate, forming a chain of giant calderas stretching almost coo miles from the Oregon—Nevada—Idaho border, northeast across Idaho to Yellowstone National Park in northwest Wyoming. Yellowstone has been perched atop the hotspot for the past 2 million years, and a 45-by-30-mile-wide caldera now forms the heart of the national park. After the ancient landscape of southern and eastern Idaho was obliterated by the eruptions, the swath of calderas in the hotspot’s wake formed the eastern two-thirds of the vast, 50-mile-wide valley now known as the Snake River Plain. The calderas eventually were buried by basalt lava flows and sediments from the Snake River and its tributaries, concealing the incredibly violent volcanic history of the Yellowstone hotspot. Yet we now know that the hotspot created much of the flat expanse of the Snake River Plain. Like a boat speeding through water and creating an arc-shaped wave in its wake, the hotspot also left in its wake a parabola-shaped pattern of high mountains and earthquake activity flanking both sides of the Snake River Plain.

scholarly journals Experimental Melting of Hydrothermally Altered Rocks: Constraints for the Generation of Low-δ18O Rhyolites in the Central Snake River Plain

2019 ◽  
Vol 60 (10) ◽  
pp. 1881-1902 ◽  
Author(s):  
Juliana Troch ◽  
Ben S Ellis ◽  
Chris Harris ◽  
Peter Ulmer ◽  
Anne-Sophie Bouvier ◽  
...  
Keyword(s):  
Hydrothermal Alteration ◽  
Large Scale ◽  
Country Rock ◽  
Isotope Composition ◽  
Snake River Plain ◽  
Snake River ◽  
Crustal Material ◽  
Yellowstone Hotspot ◽  
River Plain ◽  
Source Materials

Abstract Quantifying the relative contributions of crustal versus mantle-derived melt is important for understanding how silicic magmas are generated, stored, and interact with country rock in trans-crustal magmatic systems. Low-δ18O rhyolitic ignimbrites and lavas erupted during Miocene volcanic activity in the central Snake River Plain (14–6 Ma) have been inferred to be the result of large-scale partial or bulk melting of pre-existing hydrothermally altered lithologies of the Idaho batholith and Challis volcanic field. In this study, we assess the melting behaviour of heterogeneously altered source materials via partial melting experiments over a range of run times at conditions of 750–1000°C and 1–2 kbar, and apply our observations to current models for the petrogenesis of low-δ18O rhyolites along the Yellowstone hotspot track. Partial melt produced in the experiments inherits the bulk oxygen isotope composition from hydrothermally altered peraluminous source materials independent of the melt fraction, excluding the possibility for preferential, disequilibrium melting of 18O-depleted mineral phases during incipient melting. We propose a new model to explain the generation of low-δ18O rhyolites in the central Snake River Plain, whereby mantle-derived magmas assimilate ∼30–40% of crustal material that was hydrothermally altered at high temperatures in two stages: (1) a preceding episode of hydrothermal alteration during intrusion of Eocene plutons (‘pre-existing source’); (2) syn-magmatic hydrothermal alteration within a nested caldera complex. During assimilation, dilution of peraluminous crustal lithologies with mantle-derived magma maintains the metaluminous character of rhyolites erupted along the Yellowstone hotspot track. These results link previous models favouring melting of either pre-existing or syn-magmatically altered lithologies for the generation of low-δ18O rhyolites along the Yellowstone hotspot track and provide direct experimental observation of the chemical processes occurring during assimilation processes in magmatic environments.

Thermal structure beneath the Snake River Plain: Implications for the Yellowstone hotspot

2009 ◽  
Vol 188 (1-3) ◽  
pp. 57-67 ◽  
Author(s):  
William P. Leeman ◽  
Derek L. Schutt ◽  
Scott S. Hughes
Keyword(s):  
Thermal Structure ◽  
Snake River Plain ◽  
Snake River ◽  
Yellowstone Hotspot ◽  
River Plain

Contrasting Climatic Histories for the Snake River Plain, Idaho, Resulting from Multiple Thermal Maxima

1986 ◽  
Vol 26 (3) ◽  
pp. 321-339 ◽  
Author(s):  
Owen K. Davis ◽  
John C. Sheppard ◽  
Susan Robertson
Keyword(s):  
Pacific Northwest ◽  
Late Quaternary ◽  
High Elevation ◽  
Snake River Plain ◽  
Early Holocene ◽  
Snake River ◽  
Limiting Factor ◽  
Summer Drought ◽  
The Pacific ◽  
River Plain

Ten sites near the Snake River Plain have consistent differences in their climatic histories. Sites at low elevation reflect the “early Holocene xerothermic” of the Pacific Northwest, whereas most climatic chronologies at high elevation indicate maximum warmth or aridity somewhat later, ca. 6000 yr ago. This elevational contrast in climatic histories is duplicated at three sites from the central Snake River Plain. For sites in such close proximity, the different chronologies cannot be explained by changes in atmospheric circulation during the late Quaternary. Rather, the differences are best explained by the autecology of the plants involved and the changing seasonal climate. The seasonal climatic sequence predicted by multiple thermal maxima explains the high- and low-elevation chronologies. During the early Holocene, maximum insolation and intensified summer drought in July forced low-elevation vegetation upward. However, moisture was not a limiting factor at high elevation, where vegetation moved upward in response to increased length of growing season coincident with maximum September insolation 6000 yr ago.

scholarly journals High-temperature, low-H2O Silicic Magmas of the Yellowstone Hotspot: an Experimental Study of Rhyolite from the Bruneau–Jarbidge Eruptive Center, Central Snake River Plain, USA

2012 ◽  
Vol 53 (9) ◽  
pp. 1837-1866 ◽  
Author(s):  
Renat R. Almeev ◽  
Torsten Bolte ◽  
Barbara P. Nash ◽  
François Holtz ◽  
Martin Erdmann ◽  
...  
Keyword(s):  
Experimental Study ◽  
High Temperature ◽  
Snake River Plain ◽  
Snake River ◽  
Eruptive Center ◽  
Yellowstone Hotspot ◽  
Silicic Magmas ◽  
River Plain
Sign in / Sign up

Export Citation Format

Share Document