Geologic map of southwestern Sequoia National Park, Tulare County, California

Sisson, T. W.; Moore, James G.

doi:10.3133/ofr20131096

Cited by 5 publications

(9 citation statements)

References 11 publications

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“…There exist no quaternary faults or major geologic structures separating these catchments (Figure 7; California Geological Survey, 2023), further suggesting that the catchments have been subject to the same tectonic forcing. Both Dinkey Creek and the EFK are primarily underlain by granitic bedrock, with occasional outcrops of metamorphic bedrock (Bateman & Jones, 1972; Sisson & Moore, 2013), and both rivers feature abundance of waterfalls. Below we describe our methods for extracting river long profiles and identifying waterfalls and argue that, given the similar lithology and external forcing history between these catchments, differences in river profile morphology can potentially be explained by contrasting styles of waterfall erosion between these catchments.…”

Section: Comparison With Rivers In the Sierra Nevada Californiamentioning

confidence: 99%

Impacts of Spontaneous Waterfall Development on Bedrock River Longitudinal Profile Morphology

Rothman,

Scheingross,

McCoy

et al. 2023

JGR Earth Surface

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River profiles are shaped by climatic and tectonic history, lithology, and internal feedbacks between flow hydraulics, sediment transport and erosion. In steep channels, waterfalls may self‐form without changes in external forcing (i.e., autogenic formation) and erode at rates faster or slower than an equivalent channel without waterfalls. We use a 1‐D numerical model to investigate how self‐formed waterfalls alter the morphology of bedrock river longitudinal profiles. We modify the standard stream power model to include a slope threshold above which waterfalls spontaneously form and a rate constant allowing waterfalls to erode faster or slower than other fluvial processes. Using this model, we explore how waterfall formation alters both steady state and transient longitudinal profile forms. Our model predicts that fast waterfalls create km‐scale reaches in a dynamic equilibrium with channel slope held approximately constant at the threshold slope for waterfall formation, while slow waterfalls can create local channel slope maxima at the location of slow waterfall development. Furthermore, slow waterfall profiles integrate past base level histories, leading to multiple possible profile forms, even at steady‐state. Consistency between our model predictions and field observations of waterfall‐rich rivers in the Kings and Kaweah drainages in the southern Sierra Nevada, California, supports the hypothesis that waterfall formation can modulate river profiles in nature. Our findings may help identify how bedrock channels are influenced by waterfall erosion and aid in distinguishing between signatures of external and internal perturbations, thereby strengthening our ability to interpret past climate and tectonic changes from river longitudinal profiles.

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Section: Comparison With Rivers In the Sierra Nevada Californiamentioning

confidence: 99%

Impacts of Spontaneous Waterfall Development on Bedrock River Longitudinal Profile Morphology

Rothman,

Scheingross,

McCoy

et al. 2023

JGR Earth Surface

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“…Mineral abbreviations following Whitney and Evans (2010). Unit abbreviations following Sisson and Moore (2013).…”

Section: Hydrothermal Fluid Flow At Empire Mountainmentioning

confidence: 99%

“…The Empire Mountain skarn and its quartz diorite pluton outcrop in the northernmost extent of the pendant (Figures 1a and 1b). Over the time in which the pluton intruded during early Cretaceous subduction (∼109-105 Ma; Sisson & Moore, 2013), it released its magmatic fluid into the surrounding pendant rocks, formed massive skarn deposits consisting of garnetite and minor clinopyroxenite, and underwent remarkable hydrothermal alteration (D'Errico, 2011). Parts of the intrusion were hydrothermally altered to epidote and actinolite and are associated with the retrograde metamorphism (D'Errico, 2011).…”

Section: Geologic Settingmentioning

confidence: 99%

“…The maximal extent of the pendant is denoted by the Coyote Pass and Castle Creek plutons to the east and to the west, respectively. Both intrusions were emplaced around 98 Ma—approximately 8 Myr after the Empire Mountain pluton—and lack associated skarn deposits (Sisson & Moore, ). This suggests that all of the skarn minerals are associated with the emplacement of the Empire Mountain pluton.…”

Section: The Empire Mountain Skarnmentioning

confidence: 99%

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Reevaluating Fluid Sources During Skarn Formation: An Assessment of the Empire Mountain Skarn, Sierra Nevada, USA

Ramos

Hesse

Barnes

et al. 2018

Geochem Geophys Geosyst

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Oxygen isotope analyses of skarn minerals have long been used to fingerprint the variable fluid sources involved in skarn formation. The Empire Mountain skarn of the Sierra Nevada (California, USA) batholith is identified as a low‐δ18O skarn and is thought to form due to surface fluid involvement that was enhanced by fractures that formed during host rock brecciation. Although geochemically well characterized, the Empire Mountain skarn is less understood in terms of its hydrodynamic history. In this study, we develop a two‐dimensional model of oxygen isotope transport during high‐temperature fluid‐rock interactions to assess the mechanisms by which low‐δ18O garnets could form exclusive of brecciation. Highlighting regions nearest to the intrusion that could form garnet, we make three primary observations: (1) the oxygen isotope composition of the fluids, and not temperature, dominantly controls δ18Ogarnet values; (2) >6‰ increases in δ18Ogarnet, from negative to positive values, are observed over the maximum time frame of garnet thermodynamic stability; and (3) incremental emplacement of the intrusion can produce oscillations in δ18Ogarnet values. Without invoking brecciation, we find that low‐δ18O garnets can form without the presence of surface fluids; they instead source 18O‐depleted pore fluids from adjacent units. Further, surface fluids that do not equilibrate with the surrounding rock at depth become low‐δ18O fluid sources during later stages of pluton emplacement. This study underscores that pore fluids at depth, regardless of their equilibrium state, can act as dormant low‐δ18O fluid sources and may be responsible for low‐δ18O‐valued garnets.

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“…1) and is one of the many septa and screens representing the wall rock into which the Sierra Nevada batholith intruded. The Mineral King pendant is constructed from metaigneous volcanic (rhyolite to andesite) and intrusive (gabbro and granite) units, breccia sandstones, marbles, and marine sediment (Busby-Spera, 1983;Saleeby and Busby, 1993;Sisson and Moore, 2013). Many of these units were altered by the intrusion of fl uids and shearing (Bateman, 1992;D'Errico et al, 2012).…”

Section: Settingmentioning

confidence: 99%

Magmatic lulls in the Sierra Nevada captured in zircon from rhyolite of the Mineral King pendant, California

2014

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The Mineral King pendant in the Sierra Nevada batholith (California, USA) contains at least four rhyolite units that record highsilica volcanism during magmatic lulls in the Sierran magmatic arc. U-Th-Pb, trace element (single crystal spot analyses via sensitive high-resolution ion microprobe-reverse geometry, SHRIMP-RG), and bulk oxygen isotope analyses of zircon from these units provide a record of the age and compositional properties of the magmas that is not available from whole-rock analysis because of intense hydrothermal alteration of the pendant. U-Pb spot ages reveal that the Mineral King rhyolites are from two periods, the Early Jurassic (197 Ma) and the Early Cretaceous (134-136 Ma). These two rhyolite packages have zircons with distinct compositional trends for trace elements and δ 18 O; the Early Jurassic rhyolite shows less evidence of crustal infl uences on the rhyolites and the Early Cretaceous rhyolite shows evidence of increasing crustal infl uences and crystal recycling. These rhyolites capture evidence of magmatism during two periods of low magmatic fl ux in the Sierran Arc; however, they still show that magmas were derived from interactions of maturing continental crust, increasing from the Early to Late Jurassic. This fi nding likely refl ects the transition of the North America margin from one of docking island arcs in the Early Jurassic to one of a more mature continental arc in the Early Cretaceous. This also shows the utility in examining zircon spot ages combined with trace element and bulk isotopic composition to unlock the petrogenetic history of altered volcanic rocks.

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Geologic map of southwestern Sequoia National Park, Tulare County, California

Cited by 5 publications

References 11 publications

Impacts of Spontaneous Waterfall Development on Bedrock River Longitudinal Profile Morphology

Impacts of Spontaneous Waterfall Development on Bedrock River Longitudinal Profile Morphology

Reevaluating Fluid Sources During Skarn Formation: An Assessment of the Empire Mountain Skarn, Sierra Nevada, USA

Magmatic lulls in the Sierra Nevada captured in zircon from rhyolite of the Mineral King pendant, California

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