Peter J. Fawcett's research while affiliated with University of New Mexico and other places

Publications (98)

Article
Full-text available
Long and continuous lake sedimentary records offer enormous potential for interpreting the paleoenvironmental histories of the past and for understanding how terrestrial environments might adapt in the context of current global warming. However, sedimentary records that contain multiple glacial-interglacial cycles are scarce in continental basins....
Article
Paleosols can represent intervals of nondeposition in sedimentary packages and are used with increasing frequency as proxies for paleoenvironmental conditions during basin filling. However, the complexities of factors both internal and external to pedogenesis require consideration of paleosols in any basin or sedimentary package in a broader contex...
Article
Long, continuous records of terrestrial paleoclimate offer insights into natural climate variability and provide context for geomorphological studies, climate model reconstructions, and predictions of future climate change. STL14 is an 80 m lacustrine sediment core that archives paleoenvironmental changes at Stoneman Lake, Coconino County, Arizona,...
Chapter
The Basin of Mexico is a high elevation (2240 m asl), large (9540 km2), tectonic endorheic basin developed in the central-eastern Trans-Mexican Volcanic Belt. In 2016, the ICDP MexiDrill project recovered a total of 1152 m of sediments from a maximum depth of 520 m in Lake Chalco, in the SW of the Basin of Mexico. The upper 309.15 m (composite sequ...
Article
Full-text available
The primary scientific objective of MexiDrill, the Basin of Mexico Drilling Program, is development of a continuous, high-resolution ∼400 kyr lacustrine record of tropical North American environmental change. The field location, in the densely populated, water-stressed Mexico City region gives this record particular societal relevance. A detailed p...
Conference Paper
The Mexidrill Project recovered four overlapping sediment cores from Lake Chalco in the Basin of Mexico, near Mexico City, to reconstruct this region’s paleoclimatic history. A composite core dated with a mixture of preliminary radiocarbon dates and tephrochronology suggests that Lake Chalco was present for several hundred thousand years at this lo...
Article
Full-text available
This paper presents a short description of the coring operations undertaken to recover the full lacustrine sedimentary sequence from Chalco. Geophysical techniques were used to determine the distribution and thickness of the sediments in order to select the drilling site. Resonance frequencies determined from H/V spectral ratios were used to determ...
Article
Full-text available
Climate variability during Pleistocene glacial/interglacial transitions is well documented in marine and ice-sheet isotopic records, but terrestrial records showing the continental response to these transitions are scarce, especially for earlier in the Pleistocene. Cyclic intervals of warm interglacial and cold glacial conditions preserved in terre...
Conference Paper
In early 2016 the MexiDrill field expedition recovered over 1000 m of sediment drill cores from the Basin of Mexico at the Lake Chalco drilling site on the outskirts of Mexico City. Four holes were drilled, reaching a maximum depth of 520 m. The upper ~300 m of the sequence is composed of lacustrine mud alternating with discrete tephra layers, unde...
Conference Paper
The Valle Grande Paleo-lake in the southeastern portion of Valles Caldera, NM, U.S.A. provides a useful location to study short distance source-to-sink variation in geochemistry and mineralogy. In this study, lithium is the primary focus in order to test its effectiveness at recording past environmental change. This is possible due to the ~75 m of...
Article
Full-text available
Reconstructions of Quaternary climate are often based on the isotopic content of paleo-precipitation preserved in proxy records. While many paleo-precipitation isotope records are available, few studies have synthesized these dispersed records to explore spatial patterns of late-glacial precipitation δ18O. Here we present a synthesis of 86 globally...
Article
Previous analyses of past climate changes have often been based on site-specific isotope records from speleothems, ice cores, sediments and groundwaters. However, in most studies these dispersed records have not been integrated and synthesized in a comprehensive manner to explore the spatial patterns of precipitation isotope changes from the last i...
Conference Paper
Periods of widespread soil development in active sedimentary basins represent times when neither aggradation nor degradation occur, yet not every inferred period of depositional/erosional inactivity is marked by a paleosol in the rock record. To address some of the factors affecting soil development and preservation in a syntectonic succession of f...
Article
Full-text available
Reconstructions of Quaternary climate are often based on the isotopic content of paleo-precipitation preserved in proxy records. While many paleo-precipitation isotope records are available, few studies have synthesized these dispersed records to explore spatial patterns of late-glacial precipitation δ18O. Here we present a synthesis of 86 globally...
Article
Groundwater recharged by meteoric water supports human life by providing 2 billion people with drinking water and by supplying 40% of cropland irrigation. Whilst annual groundwater recharge rates are reported in many studies, fewer studies have explicitly quantified intra-annual (i.e., seasonal) differences in groundwater recharge. Understanding se...
Article
replying to A. M. J. Coenders-Gerrits et al. Nature 506, http://dx.doi.org/10.1038/nature12925 (2014) In their Comment, Coenders-Gerrits et al. suggest that our conclusion that transpiration dominates the terrestrial water cycle is biased by unrepresentative input data and optimistic uncertainty ranges related to runoff, interception and the isotop...
Article
Development of an accurate chronology for glacial deposits in the Sierra Nevada has long been problematic given the lack of suitable organic material for radiocarbon dating. Lichenometry initially appeared promising as ages showed an increase from cirque headwalls to down-canyon moraines. However, while Recess Peak lichen age estimates range from 2...
Article
Renewable fresh water over continents has input from precipitation and losses to the atmosphere through evaporation and transpiration. Global-scale estimates of transpiration from climate models are poorly constrained owing to large uncertainties in stomatal conductance and the lack of catchment-scale measurements required for model calibration, re...
Article
Full-text available
Oxygen isotope values of diatom silica (d18Odiatom) are increasingly used as paleoclimate proxies; however, the magnitude and timing of post-mortem alteration of d18Odiatom values has been unclear. In freshwater diatom silica from a human-made pond in northern New Mexico, post-mortem alteration of d18Odiatom values occurs within one year of sedimen...
Article
Diatom silica δ18O values from a middle-Pleistocene lacustrine core (VC-3) from the Valles Caldera record considerable (>25%) variability in the paleolake water δ18O values during interglacial Marine Isotope Stage 11 (MIS 11) and glacial MIS 12. Large scale variations (>20%) in the δ18O values of diatom silica are interpreted as extreme variations...
Article
Full-text available
The Quaternary is characterized by cyclic intervals of warm interglacial and cold glacial stages. Interglacials have typically been considered climatically more stable than glacials. In the past decade research on interglacials has revealed complex variability and instability both within and among interglacial stages. The climate transition between...
Poster
We present a high-resolution terrestrial climate record from the Valles Caldera, New Mexico which spans some 200,000 years from mid MIS 14 to early MIS 10. The glacial periods represented in the record exhibit millennial-scale Dansgaard-Oeschger like variability, especially in MIS 12, one of the coldest glacials in the Pleistocene. High resolution...
Article
Full-text available
The potential for increased drought frequency and severity linked to anthropogenic climate change in the semi-arid regions of the southwestern United States (US) is a serious concern. Multi-year droughts during the instrumental period and decadal-length droughts of the past two millennia were shorter and climatically different from the future perma...
Article
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Closed basin playas are among the most sensitive hydrologic systems globally and are excellent indicators of current and past climatic variability. This variability can significantly impact hydrologic regimes and biotic communities, and is often expressed in lake-bed deposits and shoreline features. We analyzed two playa basins in western North Ame...
Article
Rock magnetic measurements are applied to almost 80 m of lacustrine sediment (VC-3) to augment independent means of interpreting the environmental conditions of a mid-Pleistocene lake in the Valle Grande of the Valles Caldera, northern New Mexico. An age model for the core is pinned to an Ar/Ar age determination of 552 ± 3 ka for a sanidine bearing...
Presentation
How anthropogenic climate change will affect hydroclimate of the arid regions of SW North America over the next century is a concern. Model projections suggest permanent ``dust bowl-like'' conditions; however, any anthropogenic change will be superimposed on long-term natural climate variability. We use the paleoclimatic record from an 82-m deep la...
Article
Rock magnetic and paleomagnetic data from the 80 meter mid-Pleistocene Valle Grande Lake Core (VC304) recovered from paleo-lake sediments in the Valles Caldera, New Mexico, have been obtained at a sample density of about 20 cm. Paleomagnetic data from most of the core are interpreted as Brunhes normal polarity, consistent with an Ar/Ar date of 552...
Article
Playa lakes in the Chihuahuan Desert, northern Mexico respond to regional climatic signals and display large interannual variability in the timing and duration of flooding. These playas, located on the boundary of the summer North American monsoon system and the winter frontal system, are in a critical location for understanding the variability of...
Article
An 82-m deep lacustrine sediment core from the Valles Caldera, northern New Mexico reveals details of climate change over two glacial cycles in the middle Pleistocene. Core VC-3, taken from the Valle Grande, has a basal 40Ar/39Ar date of 552 kyr from a tephra associated with the eruption of the South Mountain rhyolite which formed the lake. A varie...
Article
Oxygen isotope values of biogenic silica from diatom frustules are a commonly used proxy in freshwater and marine environments, and provide a valuable archive of paleoclimatic information such as temperature and water cycle processes. Advances in analytical techniques have made oxygen isotope measurements of diatom silica more robust; however, to d...
Article
Monsoon precipitation is vital for the arid regions of Southwestern United States, but currently there are insufficient quantitative paleoclimate data for parameterizing climate models. We studied an 82-m lacustrine sediment core from Valles Caldera, Northern New Mexico. The basal age of the core is 552 ±3 kyr determined by dating of a tephra layer...
Article
Full-text available
High-resolution pollen and magnetic susceptibility (MS) data from a sediment core from an alpine bog (3100 m) in the Sangre de Cristo Mountains (New Mexico) record variations in treeline elevation and in sedimentation for the last 14 ka (cal yr BP). Strong correspondence between the paleovegetation and the MS profile suggests that both records can...
Article
Lacustrine deposits dating back to the middle Pleistocene were recovered from Valles Caldera, located in Northern New Mexico. The core (82 m long) contained ~75 meters of lacustrine sediments. The age of the sediments was constrained by Ar-Ar dating of a primary tephra layer from the base of the core, in combination with correlation to the deep-sea...
Article
Full-text available
The advent of high-resolution, precise, back-pack portable terrestrial lidar scanners (TLS) provides a revolutionary new tool for obtaining quantitative, high-resolution (2-mm to 30-mm point spacing) measurements of landscape surface features. Moreover, data collected using these instruments allow observation of geomorphic processes in systems that...
Article
Continuous high-resolution pollen data for the past 225ka from sediments in Bear Lake, Utah–Idaho reflect changes in vegetation and climate that correlate well with variations in summer insolation and global ice-volume during MIS 1 through 7. Spectral analysis of the pollen data identified peaks at 21–22 and 100ka corresponding to periodicities in...
Article
Valles Caldera, located in Northern New Mexico, contains lacustrine deposits dating back to the middle Pleistocene. An 82 m long core containing ~75 meters of lacustrine sediments was recovered from Valles Caldera in 2004. The age of the sediments was constrained by Ar-Ar dating of a primary tephra layer from the base of the core, in combination wi...
Article
Full-text available
A long-lived middle Pleistocene lake formed in the Valle Grande, a large moat valley of the Valles Caldera in northern New Mexico, when a post-caldera eruption (South Mountain rhyolite) dammed the drainage out of the caldera. The deposits of this lake were cored in May 2004 (GLAD5 project, hole VC-3) and 81 m of mostly lacustrine silty mud were rec...
Article
Biogenic opal in the form of diatom frustules is abundant in lacustrine and marine environments throughout the Cenozoic. Oxygen isotope ratios preserved in the SiO2 of diatom frustules provide a valuable archive of paleoclimatic data, such as changes in temperature and precipitation/evaporation. However, oxygen isotope analysis of diatom silica is...
Article
A long-lived middle Pleistocene lake formed in the Valle Grande, a large moat valley of the Valles Caldera in northern New Mexico, when a post-caldera eruption (South Mountain rhyolite) dammed the drainage out of the caldera. The deposits of this lake were cored in May 2004 (GLAD5 project, hole VC-3) and 81 m of mostly lacustrine silty mud was reco...
Article
Lake-level variations preserved as beach ridges in the Laguna El Fresnal and Laguna Santa María subbasins, northern Mexico, record millennially spaced episodes of increased precipitation during the Holocene epoch. We find that the early, middle, and late Holocene were punctuated by periods wet enough to establish large pluvial lakes in currently dr...
Article
An 81-meter lacustrine core recovered from the Valle Grande located within the Valles Caldera, New Mexico is a valuable indicator of regional changes in climatic variations during the mid-Pleistocene. Geochemical variations in the core are being examined as a proxy for lake level and climate change. The caldera's limited watershed is dominated by r...
Article
The Valles Caldera in the Jemez Mountains of northern New Mexico contains a thick sequence of lacustrine and volcaniclastic sediments that date from the inception of the caldera (c.a. 1.25 Myr). Lakes formed in the caldera immediately after its formation and existed for some period of time before the caldera wall was breached. A major lake formed d...
Article
The 22-km diameter Valles caldera in the Jemez Mountains of northern New Mexico contains a thick sequence of lacustrine sediments and hydromagmatic deposits that date from the inception of the caldera (c.a. 1.25 Myr). Geologic mapping shows that lakes formed in the caldera immediately after its formation and existed for some period of time before t...
Article
The summertime sources and transport pathways of water vapor into the interior of southwestern North America are examined in a high-resolution mesoscale model simulation. A complex multi-stage transport pathway is associated with a pronounced diurnal cycle of deep convection and low-level wind systems. Daytime thermal pumping of moisture from the G...
Article
We compare several high-resolution paleoclimatic records from western North America that indicate near-synchronous millennial-scale climate variability through much of the Holocene. A Holocene pluvial lake system in northern Chihuahua, Mexico alternates between lake highstands representing cooler and wetter conditions and dry playa conditions repre...