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L.J. Patrick Muffler

Publications and source records attributed to L.J. Patrick Muffler.

At least 19 recordsLinked to original sources
USGS2024

Cosmogenic 21Ne exposure ages on late Pleistocene moraines in Lassen Volcanic National Park, California, USA

We report new cosmogenic 21 Ne in quartz exposure ages from 18 samples on three distinct moraines deposited in the Lost Creek drainage, approximately 3–7 km down-valley from Lassen Peak in Lassen Volcanic National Park. Although measuring 21 Ne in quartz is generally straightforward, accurate 21 Ne exposure dating of deposits of late Pleistocene is rarely possible due to the significant quantities of non-cosmogenic 21 Ne present in most lithologies. Young quartz-bearing volcanic rocks have been observed to be an exception. We take advantage of moraine boulders sourced from the ∼ 28 ka dacite of Lassen Peak to generate a chronology of alpine deglaciation in Lassen Volcanic National Park. Ages from three distinct moraines are in stratigraphic order at 22.1 ± 3.8, 20.2 ± 2.4, and 15.3 ± 3.8 ka and generally agree with other terminal and some recessional moraine ages across the Cascade Range and Sierra Nevada of the western United States. To date, these are among the youngest surfaces ever dated using cosmogenic 21 Ne and provide a cost-effective proof-of-concept approach to dating moraines where applicable.

California↗
USGS2023

Paleomagnetically defined brief lifespans for two large shield volcanoes in the Cascades Arc

Mafic to intermediate shield volcanoes with multi-cubic-kilometer eruptive volumes are common in the Cascades Volcanic Arc, but little is known about their eruptive histories as either singular or sustained episodes, or the total time required for their construction. Paleomagnetic data were collected from the lava flows of Ash Creek Butte (17 sites) and Crater Mountain (14 sites) in northern California; both volcanoes are large shields with total volumes of ∼11 km 3 each. Tightly clustered paleomagnetic results at both volcanoes, when coupled with analysis of geomagnetic secular variation, suggest that each edifice was built in only a few centuries, possibly in as little time as 50–90 years, indicating sub-century to century scale eruptive durations for two sizeable regional shield volcanoes within the Cascades Arc. These rapidly built shield volcanoes are substantially larger than typically defined monogenetic volcanoes, yet both are wholly formed within a single ‘episode’ at the limits of temporal resolution. Paleomagnetic methods provide a high-resolution tool that can be applied to understanding the tempo of regional volcanism in arcs.

California, Oregon, Washington↗
USGS2022

Effects of structure and volcanic stratigraphy on groundwater and surface water flow: Hat Creek basin, California, USA

Hydrogeologic systems in the southern Cascade Range in California (USA) develop in volcanic rocks where morphology, stratigraphy, extensional structures, and attendant basin geometry play a central role in groundwater flow paths, groundwater/surface-water interactions, and spring discharge locations. High-volume springs (greater than 3 m 3 /s) flow from basin-filling (<800 ka) volcanic rocks in the Hat Creek and Fall River tributaries and contribute approximately half of the average annual flow of the Pit River, the largest tributary to Shasta Lake. A hydrogeologic conceptual framework is constructed for the Hat Creek basin combining new geologic mapping, water-well lithologic logs, a database of active faults, LiDAR mapping of faults and volcanic landforms, streamflow measurements and airborne thermal infrared remote sensing of stream temperature. These data are used to integrate the geologic structure and the volcanic and volcaniclastic stratigraphy to create a three-dimensional interpretation of the hydrogeology in the basin. Two large streamflow gains from focused groundwater discharge near Big Spring and north of Sugarloaf Peak result from geologic barriers that restrict lateral groundwater flow and force water into Hat Creek. The inferred groundwater-flow barriers divide the aquifer system into at least three leaky compartments. The two downstream compartments lose streamflow in the upstream reaches (immediately downstream of the groundwater-flow barriers) and gain in downstream reaches with the greatest inflows immediately upstream of the barriers.

California↗
USGS2021

A multidisciplinary investigation into the eruptive style, processes, and duration of a Cascades back-arc tholeiitic basalt: A case study of the Brushy Butte flow field, northern California, United States

The Cascades back-arc in northern California is dominated by monogenetic tholeiitic basalts that erupted throughout the Pleistocene. Elucidating their eruptive history and processes is important for understanding potential future eruptions here. We focus on the well-exposed monogenetic volcano that emplaced the Brushy Butte flow field, which constructed a ∼150 m tall edifice, has flow lobes up to >10 km long, and in total covers ∼150 km 2 with an eruptive volume of 3.5 km 3 . We use a multidisciplinary approach of field mapping, petrography, geochemistry, paleomagnetism, geochronology, and lidar imagery to unravel the eruptive history and processes that emplaced this flow field. Tholeiitic basalts in northern California have diverse surface morphology and vegetation cover but similar petrographic appearances, which makes them hard to distinguish in the field. Geochemistry and paleomagnetism offer an independent means of distinguishing tholeiitic basalts. Brushy Butte flow field lavas are similar in major-oxide and trace-element abundances but differ from adjacent tholeiitic basalts. This is also apparent in remanent magnetic directions. Additionally, paleomagnetism indicates that the flow field was emplaced during a geologically brief time interval (10–20 years), which 36 Cl cosmogenic dating puts at 35.7 ± 1.7 ka. Lidar imagery shows that these flows erupted from at least 28 vents encompassing multiple scoria cones, spatter cones, and craters. Flows can be grouped into four pulses using stratigraphic position and volume. Pulse 1 is the most voluminous, comprising eight eruptions and ∼2.3 km 3 . Each subsequent pulse started rapidly but decayed quickly, and each successive pulse erupted less lava (i.e., 2.3 km 3 for pulse 1, 0.6 km 3 for pulse 2, 0.3 km 3 for pulse 3, and 0.2 km 3 for pulse 4). Many of these flows host well-established lava channels and levees (with channel breakouts) that lead to lava fans, with some flows hosting lava ponds. Similar flow features from tholeiitic eruptions elsewhere demonstrate that these morphologies generally occur over weeks, months, or longer (e.g., Puʻu ʻŌʻō eruption at K–llauea, Hawaiʻi). This multidisciplinary study shows the range of eruptive styles and durations of a Cascades back-arc eruption and illustrates how potential future tholeiitic eruptive activity in the western United States might progress.

California↗
USGS2020

Simultaneous Middle Pleistocene eruption of three widespread tholeiitic basalts in northern California (USA): Insights into crustal magma transport in an actively extending back arc

Mapping and chronology are central to understanding spatiotemporal volcanic trends in diverse tectonic settings. The Cascades back arc in northern California (USA) hosts abundant lava flows and normal faults, but tholeiitic basalts older than 200 ka are difficult to discriminate by classic mapping methods. Paleomagnetism and chemistry offer independent means of correlating basalts, including the Tennant, Dry Lake, and Hammond Crossing basalt fields. Paleomagnetic analysis of these chemically similar basalts yield notable overlap, with statistical analysis yielding 7 chances in 1,000,000 that their similar mean remanent directions are random. These basalts also have overlapping 40 Ar/ 39 Ar ages of 272.5 ± 30.6 ka (Tennant), 305.8 ± 23.9 ka (Dry Lake), and 300.4 ± 15.2 and 322.6 ± 17.4 ka (Hammond Crossing). Chemical and paleomagnetic analyses indicate that these spatially distributed basalts represent simultaneous (<100 yr uncertainty) eruptions, and thus we use 305.5 ± 9.8 ka (weighted mean) as the eruption age. Their vents align on a N25°W trend over a distance of 39 km. Tennant erupted the largest volume (3.55 ± 0.75 km 3 ) at the highest elevation; both factors decay to the south-southeast at Dry Lake (0.75 ± 0.15 km 3 ) and Hammond Crossing (0.15 ± 0.05 km 3 ). We propose vertical magma ascent beneath the Tennant vent area, where the most evolved, high-SiO 2 magma erupted, with lateral dike propagation in the brittle crust. Propagation was near orthogonal to east-west extension (0.3–0.6 mm/yr) along north-northwest–trending normal faults.

California↗
USGS2019

Eruption age and duration of the ~9 km3 Burney Mountain dacite dome complex, northern California

At ~9 km3, the six dacite domes of Burney Mountain (db1–db6) constitute the most voluminous Quaternary dome complex in the Cascades volcanic arc. Whole-rock geochemistry, electron microprobe, and petrographic data indicate that the domes are magmatically related, which, when integrated with geomorphology and stratigraphy, indicate early (db1, db2, db3) and late (db4, db5, db6) erupted groups. We present 40Ar/39Ar ages of 271.9±4.6 ka (db1), 280.8±8.2 and 281.7±6.8 ka (db2), and 290.2±6.0 ka (db3) along with a previous age of 280±12 ka (db1). These ages scatter over 20 kyr, whereas remanent magnetic directions are similar between 53.3–59.0° inclination and 352.7–355.9° declination. The latter dataset indicates that the dacite domes were emplaced over a geologically brief time interval; not thousands of years. Crystal-size distribution patterns of plagioclase were used to calculate residence times, which we use to infer the duration over which the eruptions likely occurred. Three slopes represent three populations of plagioclase crystals (fine-grained groundmass, coarse-grained groundmass, phenocrysts). A commonly used growth rate for plagioclase in dacitic magmas (10-10 mm/s) yields 9–10 years of growth for the coarse-grained groundmass (early erupted domes of db1, db2, db3), whereas plagioclase in the fine-grained groundmass (late erupted domes of db4, db5, db6) grew over 4–5 years. All plagioclase phenocrysts have apparent residence times of 26–36 years; however, they contain high An>70 resorbed cores with sieve textures, which have euhedral, lower An<65 overgrowth rims. Similarities in chemistry between groundmass plagioclase and phenocryst overgrowth rims indicate that they grew concurrently, and we therefore propose that both have similar residence times. Thus, the Burney Mountain dacite dome complex was emplaced during a single eruptive episode over the course of years to decades at 281.1±4.8 ka (weighted mean age).

California↗
USGS2019

Pleistocene hydrothermal activity on Brokeoff volcano and in the Maidu volcanic center, Lassen Peak area, northeast California: Evolution of magmatic-hydrothermal systems on stratovolcanoes

Partially eroded stratovolcanoes worldwide, notably Mounts Rainier and Adams in the Cascades and several volcanoes in Japan, record episodic periods of eruption and geothermal activity that produce zones of hydrothermal alteration. The partly eroded core of late Pleistocene Brokeoff volcano on the south side of Lassen Peak exposes the upper 1 km of multiple ancient (ca. 410–300 ka) magmatic-hydrothermal alteration zones in a 3.5 by 5 km area that allows characterization of the three-dimensional hydrothermal evolution of the volcano. Both acid- and neutral-pH hydrothermal solutions produced distinctive alteration mineral assemblages in close proximity. Early hydrothermal activity is characterized by alunite-rich alteration that is temporally and spatially related to shallow intrusions in the center of the volcano. Younger acid alteration and a large area of neutral-pH alteration formed along the volcano’s flanks. The neutral-pH alteration is vertically zoned over 1000 m from shallow zeolite ± adularia through intermediate argillic (smectite-pyrite ± illite) to deep propylitic (chlorite-calcite-albite-illite) alteration. Pleistocene alteration is partly overprinted by surficial, steam-heated alteration related to Lassen’s modern hydrothermal activity. A large (∼3.5 km 2 ), shallow (≤300 m), ca. 1.5 Ma alunite-rich magmatic-hydrothermal alteration zone is exposed on the northeast flank of the nearby Maidu volcanic center.

California↗
USGS2017

Overview for geologic field-trip guides to volcanoes of the Cascades Arc in northern California

The California Cascades field trip is a loop beginning and ending in Portland, Oregon. The route of day 1 goes eastward across the Cascades just south of Mount Hood, travels south along the east side of the Cascades for an overview of the central Oregon volcanoes (including Three Sisters and Newberry Volcano), and ends at Klamath Falls, Oregon. Day 2 and much of day 3 focus on Medicine Lake Volcano. The latter part of day 3 consists of a drive south across the Pit River into the Hat Creek Valley and then clockwise around Lassen Volcanic Center to the town of Chester, California. Day 4 goes from south to north across Lassen Volcanic Center, ending at Burney, California. Day 5 and the first part of day 6 follow a clockwise route around Mount Shasta. The trip returns to Portland on the latter part of day 6, west of the Cascades through the Klamath Mountains and the Willamette Valley. Each of the three sections of this guidebook addresses one of the major volcanic regions: Lassen Volcanic Center (a volcanic field that spans the volcanic arc), Mount Shasta (a fore-arc stratocone), and Medicine Lake Volcano (a rear-arc, shield-shaped edifice). Each section of the guide provides (1) an overview of the extensive field and laboratory studies, (2) an introduction to the literature, and (3) directions to the most important and accessible field localities. The field-trip sections contain far more stops than can possibly be visited in the actual 6-day 2017 IAVCEI excursion from Portland. We have included extra stops in order to provide a field-trip guide that will have lasting utility for those who may have more time or may want to emphasize one particular volcanic area.

California↗
USGS2017

Robust 24 ± 6 ka 40 Ar/ 39 Ar age of a low-potassium tholeiitic basalt in the Lassen region of NE California

40 Ar/ 39 Ar ages on the Hat Creek Basalt (HCB) and stratigraphically related lava flows show that latest Pleistocene tholeiitic basalt with very low K 2 O can be dated reliably. The HCB underlies &sim; 15 ka glacial gravel and overlies four andesite and basaltic andesite lava flows that yield 40 Ar/ 39 Ar ages of 38 &plusmn; 7 ka (Cinder Butte; 1.65% K 2 O), 46 &plusmn; 7 ka (Sugarloaf Peak; 1.85% K 2 O), 67 &plusmn; 4 ka (Little Potato Butte; 1.42% K 2 O) and 77 &plusmn; 11 ka (Potato Butte; 1.62% K 2 O). Given these firm age brackets, we then dated the HCB directly. One sample (0.19% K 2 O) clearly failed the criteria for plateau-age interpretation, but the inverse isochron age of 26 &plusmn; 6 ka is seductively appealing. A second sample (0.17% K 2 O) yielded concordant plateau, integrated (total fusion), and inverse isochron ages of 26 &plusmn; 18, 30 &plusmn; 20 and 24 &plusmn; 6 ka, all within the time bracket determined by stratigraphic relations; the inverse isochron age of 24 &plusmn; 6 ka is preferred. As with all isotopically determined ages, confidence in the results is significantly enhanced when additional constraints imposed by other isotopic ages within a stratigraphic context are taken into account.

California↗
USGS2016

Structure of the Hat Creek graben region: Implications for the structure of the Hat Creek graben and transfer of right-lateral shear from the Walker Lane north of Lassen Peak, northern California, from gravity and magnetic anomalies

Interpretation of magnetic and new gravity data provides constraints on the geometry of the Hat Creek Fault, the amount of right-lateral offset in the area between Mt. Shasta and Lassen Peak, and confirmation of the influence of pre-existing structure on Quaternary faulting. Neogene volcanic rocks coincide with short-wavelength magnetic anomalies of both normal and reversed polarity, whereas a markedly smoother magnetic field occurs over the Klamath Mountains and its Paleogene cover. Although the magnetic field over the Neogene volcanic rocks is complex, the Hat Creek Fault, which is one of the most prominent normal faults in the region and forms the eastern margin of the Hat Creek Valley, is marked by the eastern edge of a north-trending magnetic and gravity high 20-30 km long. Modeling of these anomalies indicates that the fault is a steeply dipping (~75-85&deg;) structure. The spatial relationship of the fault as modeled by the potential-field data, the youngest strand of the fault, and relocated seismicity suggests that deformation continues to step westward across the valley, consistent with a component of right-lateral slip in an extensional environment. Filtered aeromagnetic data highlight a concealed magnetic body of Mesozoic or older age north of Hat Creek Valley. The body&rsquo;s northwest margin strikes northeast and is linear over a distance of ~40 km. Within the resolution of the aeromagnetic data (1-2 km), we discern no right-lateral offset of this body. Furthermore, Quaternary faults change strike or appear to end, as if to avoid this concealed magnetic body and to pass along its southeast edge, suggesting that pre-existing crustal structure influenced younger faulting, as previously proposed based on gravity data.

California, Nevada↗
USGS2016

A biographical memoir of Donald Edward White

Donald E. White was a leading scientist for the U.S. Geological Survey, where his career was devoted almost entirely to the study of hydrothermal processes in the Earth’s crust, from the dual perspectives of active geothermal systems and of extinct hydrothermal systems now represented only by ore deposits and alteration patterns. White was devoted to analyzing the mechanisms by which ore-forming metals are concentrated, transported, and deposited. His early work on antimony deposits and on mercury transport led to the understanding that these elements, as well as some precious metals, were concentrated in hydrothermal convection systems characterized by dilute chloride waters of predominantly meteoric origin. He concluded, on the other hand, that base metals required more concentrated brines, as was impressively confirmed in the early 1960s by the discovery of the metal-rich fluids of the Salton Sea geothermal system and subsequently by the recognition of sulfide-depositing hydrothermal systems on the sea floor. His studies of active hot-spring systems elucidated the principles of geyser activity and provided the scientific foundation for research programs aimed at the understanding of geothermal systems throughout the world.

Article↗
USGS2015

Geologic field-trip guide to Lassen Volcanic National Park and vicinity, California

This geologic field-trip guide provides an overview of Quaternary volcanism in and around Lassen Volcanic National Park in northern California. The guide begins with a comprehensive overview of the geologic framework and the stratigraphic terminology of the Lassen region, based primarily on the &ldquo;Geologic map of Lassen Volcanic National Park and vicinity&rdquo; (Clynne and Muffler, 2010). The geologic overview is then followed by detailed road logs describing the volcanic features that can readily be seen in the park and its periphery. Twenty-one designated stops provide detailed explanations of important volcanic features. The guide also includes mileage logs along the highways leading into the park from the major nearby communities. The field-trip guide is intended to be a flexible document that can be adapted to the needs of a visitor approaching the park from any direction.

California↗
USGS2000

Revised age of the Rockland tephra, northern California: Implications for climate and stratigraphic reconstructions in the western United States: Reply

Sarna-Wojcicki suggests that the 40 Ar/ 39 Ar age of 614 ± 8 ka for the Rockland tephra ( Lanphere et al., 1999 ) is too old because of the presence of xenocrystic plagioclase. The Rockland tephra is indeed full of lithic debris that can be seen at any well-exposed outcrop of ash-flow or air-fall deposits. In order to minimize contamination, we selected pumice lumps known to be representative of the Rockland magma. Plagioclase in the pumice lumps forms a homogeneous population of weakly zoned phenocrysts. By contrast, plagioclase from the intermediate to silicic volcanic lithic fragments in the Rockland tephra typically displays complex zoning, variable resorption patterns and strong discontinuities. Such plagioclase would be readily recognizable if present in the Rockland magma. We saw no petrographic evidence that the Rockland magma was contaminated with xenocrystic plagioclase. The pumice lumps were carefully cleaned before mineral separations were made.

California↗
USGS1979

Assessment of geothermal resources of the United States: 1978

The geothermal resource assessment presented in this Circular is a refinement and updating of USGS Circular 726. Nonproprietary information available in June 1978 is used to assess geothermal energy in the ground and, when possible, to evaluate the fraction that might be recovered at the surface. Five categories of geothermal energy are discussed: a. Conduction-dominated regimes b. Igneous-related geothermal systems c. High-temperature (>1500C) and intermediate-temperature (90°-150°C) hydrothermal convection systems d. Low-temperature (<900C) geothermal waters e. Geopressured-geothermal energy (both thermal energy and energy from dissolved methane). Assessment data are presented on three colored maps prepared in cooperation with the National Oceanic and Atmospheric Administration.

Circular↗
USGS1973

Resistivity, self‐potential, and induced‐polarization surveys of a vapor‐dominated geothermal system

The Mud Volcano area in Yellowstone National Park provides an example of a vapor‐dominated geothermal system. A test well drilled to a depth of about 347 ft penetrated the vapor‐dominated reservoir at a depth of less than 300 ft. Subsequently, 16 vertical electrical soundings (VES) of the Schlumberger type were made along a 3.7‐mile traverse to evaluate the electrical resistivity distribution within this geothermal field. Interpretation of the VES curves by computer modeling indicates that the vapor‐dominated layer has a resistivity of about 75–130 ohm‐m and that its lateral extent is about 1 mile. It is characteristically overlain by a low‐resistivity layer of about 2–6.5 ohm‐m, and it is laterally confined by a layer of about 30 ohm‐m. This 30‐ohm‐m layer, which probably represents hot water circulating in low‐porosity rocks, also underlies most of the survey at an average depth of about 1000 ft. Horizontal resistivity profiles, measured with two electrode spacings of an AMN array, qualitatively corroborate the sounding interpretation. The profiling data delineate the southeast boundary of the geothermal field as a distinct transition from low to high apparent resistivities. The northwest boundary is less distinctly defined because of the presence of thick lake deposits of low resistivities. A broad positive self‐potential anomaly is observed over the geothermal field, and it is interpretable in terms of the circulation of the thermal waters. Induced‐polarization anomalies were obtained at the northwest boundary and near the southeast boundary of the vapor‐dominated field. These anomalies probably are caused by relatively high concentrations of pyrite.

Wyoming↗