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Marc W. Caffee

Publications and source records attributed to Marc W. Caffee.

8 recordsLinked to original sources
USGS2022

Yukon River incision drove organic carbon burial in the Bering Sea during global climate changes at 2.6 and 1 Ma

River erosion affects the carbon cycle and thus climate by exporting terrigenous carbon to seafloor sediment and by nourishing CO 2 -consuming marine life. The Yukon River–Bering Sea system preserves rare source-to-sink records of these processes across profound changes in global climate during the past 5 million years (Ma). Here, we expand the terrestrial erosion record by dating terraces along the Charley River, Alaska, and explore linkages among previously published Yukon River tributary incision chronologies and Bering Sea sedimentation. Cosmogenic 26 Al / 10 Be "> isochron burial ages of Charley River terraces match previously documented central Yukon River tributary incision from 2.6 to 1.6 Ma during Pliocene–Pleistocene glacial expansion, and at 1.1 Ma during the 1.2–0.7 Ma Middle Pleistocene climate transition. Bering Sea sediments preserve 2–4-fold rate increases of Yukon River-derived continental detritus, terrestrial and marine organic carbon, and silicate microfossil deposition at 2.6–2.1 and 1.1–0.8 Ma. These tightly coupled records demonstrate elevated terrigenous nutrient and carbon export and concomitant Bering Sea productivity in response to climate-forced Yukon River incision. Carbon burial related to accelerated terrestrial erosion may contribute to CO 2 drawdown across the Pliocene–Pleistocene and Middle Pleistocene climate transitions observed in many proxy records worldwide.

Alaska, British Columbia, Northwest Territories, Y↗
USGS2020

Geologic map of the Homestake Reservoir 7.5′ quadrangle, Lake, Pitkin, and Eagle Counties, Colorado

The Homestake Reservoir 7.5' quadrangle lies at the northwestern end of the Upper Arkansas Valley, and headwaters of the Arkansas River, and the Roaring Fork, Fryingpan, and Eagle Rivers of the Colorado River system. The quadrangle lies within tectonic provinces of the 1.4 giga-annum (Ga) Picuris orogeny and includes the late Paleozoic Ancestral Rockies, Late Cretaceous-Paleocene Laramide orogeny, Oligocene-to-Miocene and Pliocene? volcanism, and Miocene to the present Rio Grande rift extensional tectonics. In the eastern half of the quadrangle, high-angle, east-dipping, Neogene normal faults displace Proterozoic rocks, and locally Miocene-to-Pliocene? volcanic rocks. Many quartz veins and hydrothermally altered zones are exposed along the eastern flank of the quadrangle, indicative of the multiple tectonic episodes the region has experienced. The main intent of the map is to unravel the structural complexity by partitioning the structures and volcanism within the appropriate geologic interval. This ultimately permits accurate identification of geomorphic features suitable for chronologies related to landscape evolution studies, seismic and other natural hazard identification, ground and surface water modeling, and paleoclimatic studies. Within the western half of the quadrangle, Mesoproterozoic and Paleoproterozoic igneous and metamorphic rocks of 1.4 Ga St. Kevin Granite and 1.8–1.7 Ga Biotite gneiss and schist, respectively, are uplifted along the generally east-dipping, high-angle Sawatch fault system. In the northwest portion of the quadrangle, strands of the Homestake shear zone have been mapped, dated and assigned to the 1.4 Ga Picuris orogeny of northern New Mexico. 10 Be and 26 Al cosmogenic nuclide ages of the youngest glacial deposits indicate a last glacial maximum age of about 22–21 kilo-annum (ka) and complete deglaciation by about 14 kilo-annum, supported by chronologic studies in adjacent drainages. The Turquoise Lake impounding lateral and terminal moraine complex was deposited during late Pleistocene glacial maximum ~22–21 ka. No late Pleistocene tectonic activity is apparent within the quadrangle.

Colorado↗
USGS2019

Climate during the Last Glacial Maximum in the northern Sawatch Range, Colorado, USA

Temperature-index modeling is used to determine the magnitude of temperature depression in the northern Sawatch Range required to maintain steady-state mass balances of six reconstructed glaciers at their extent during the local Last Glacial Maximum (LLGM), dated at ~21 ka. Assuming no significant differences in precipitation compared to modern values, mean annual temperatures in the region were on average 8.8 + 0.5/– 0.8 °C cooler than they are today. Allowing for modest (± 10 cm) increases or decreases in precipitation, required temperature depressions only differ by ±0.2 °C. Temperature depression in the northern Sawatch Range is consistent, although slightly greater, with those determined in other ranges in Colorado using similar approaches. The estimates presented here are, however, substantially less than those suggested by several downscaled simulations of global Last Glacial Maximum (LGM) climate, that might be due to the need for improved calibration of such downscalings, or the models from which they are derived. Our estimates of LGM temperature depression are considerably greater than that previously determined in the study area and those in two other ranges in Colorado derived using different methodologies, the latter being most likely responsible for the discrepancies.

Colorado↗
USGS2019

Pace and process of active folding and fluvial incision across the Kantishna Hills anticline, central Alaska

Rates of northern Alaska Range thrust system deformation are poorly constrained. Shortening at the system's west end is focused on the Kantishna Hills anticline. Where the McKinley River cuts across the anticline, the landscape records both Late Pleistocene deformation and climatic change. New optically stimulated luminescence and cosmogenic 10 Be depth profile dates of three McKinley River terrace levels (~22, ~18, and ~14–9 ka) match independently determined ages of local glacial maxima, consistent with climate‐driven terrace formation. Terrace ages quantify rates of differential bedrock incision, uplift, and shortening based on fault depth inferred from microseismicity. Differential rock uplift and incision (≤1.4 m/kyr) drive significant channel width narrowing in response to ongoing folding at a shortening rate of ~1.2 m/kyr. Our results constrain northern Alaska Range thrust system deformation rates, and elucidate superimposed landscape responses to Late Pleistocene climate change and active folding with broad geomorphic implications.

Alaska↗
USGS2018

Geologic map of the Leadville North 7.5’ quadrangle, Eagle and Lake Counties, Colorado

The Leadville North 7.5’ quadrangle lies at the northern end of the Upper Arkansas Valley, where the Continental Divide at Tennessee Pass creates a low drainage divide between the Colorado and Arkansas River watersheds. In the eastern half of the quadrangle, the Paleozoic sedimentary section dips generally 20–30 degrees east. At Tennessee Pass and Missouri Hill, the core of the Sawatch anticlinorium is mapped as displaying a tight hanging-wall syncline and foot-wall anticline within the basement-cored structure. High-angle, west-dipping, Neogene normal faults cut the eastern margin of the broad, Sawatch anticlinorium. Minor displacements along high-angle, east- and west-dipping Laramide reverse faults occurred in the core of the north-plunging anticlinorium along the western and eastern flanks of Missouri Hill. Within the western half of the quadrangle, Meso- and Paleoproterozoic metamorphic and igneous rocks are uplifted along the generally east-dipping, high-angle Sawatch fault system and are overlain by at least three generations of glacial deposits in the western part of the quadrangle. 10 Be and 26 Al cosmogenic nuclide ages of the youngest glacial deposits indicate a last glacial maximum age of about 21–22 kilo-annum and complete deglaciation by about 14 kilo-annum, supported by chronologic studies in adjacent drainages. No late Pleistocene tectonic activity is apparent within the quadrangle.

Colorado↗
USGS2017

Cosmogenic nuclide age estimate for Laurentide Ice Sheet recession from the terminal moraine, New Jersey, USA, and constraints on latest Pleistocene ice sheet history

The time at which the Laurentide Ice Sheet reached its maximum extent and subsequently retreated from its terminal moraine in New Jersey has been constrained by bracketing radiocarbon ages on preglacial and postglacial sediments. Here, we present measurements of in situ produced 10 Be and 26 Al in 16 quartz-bearing samples collected from bedrock outcrops and glacial erratics just north of the terminal moraine in north-central New Jersey; as such, our ages represent a minimum limit on the timing of ice recession from the moraine. The data set includes field and laboratory replicates, as well as replication of the entire data set five years after initial measurement. We find that recession of the Laurentide Ice Sheet from the terminal moraine in New Jersey began before 25.2±2.1 ka ( 10 Be, n=16, average, 1 standard deviation). This cosmogenic nuclide exposure age is consistent with existing limiting radiocarbon ages in the study area and cosmogenic nuclide exposure ages from the terminal moraine on Martha’s Vineyard ~300 km to the northeast. The age we propose for Laurentide Ice Sheet retreat from the New Jersey terminal position is broadly consistent with regional and global climate records of the last glacial maximum termination and records of fluvial incision.

New Jersey↗
USGS2016

Terrestrial cosmogenic surface exposure dating of glacial and associated landforms in the Ruby Mountains-East Humboldt Range of central Nevada and along the northeastern flank of the Sierra Nevada

Deposits near Lamoille in the Ruby Mountains-East Humboldt Range of central Nevada and at Woodfords on the eastern edge of the Sierra Nevada each record two distinct glacial advances. We compare independent assessments of terrestrial cosmogenic nuclide (TCN) surface exposure ages for glacial deposits that we have determined to those obtained by others at the two sites. At each site, TCN ages of boulders on moraines of the younger advance are between 15 and 30 ka and may be associated with marine oxygen isotope stage (MIS) 2. At Woodfords, TCN ages of boulders on the moraine of the older advance are younger than ~ 60 ka and possibly formed during MIS 4, whereas boulders on the correlative outwash surface show ages approaching 140 ka (~ MIS 6). The TCN ages of boulders on older glacial moraine at Woodfords thus appear to severely underestimate the true age of the glacial advance responsible for the deposit. The same is possibly true at Lamoille where clasts sampled from the moraine of the oldest advance have ages ranging between 20 and 40 ka with a single outlier age of ~ 80 ka. The underestimations are attributed to the degradation and denudation of older moraine crests. Noting that boulder ages on the older advances at each site overlap significantly with MIS 2. We speculate that erosion of the older moraines has been episodic, with a pulse of denudation accompanying the inception of MIS 2 glaciation.

Nevada↗