Julio L Betancourt

Datos Biográficos

ID240213
NOMBREJulio L Betancourt
NOMBRESJulio L
APELLIDOBetancourt
FIRMABETANCOURT J L
AFILIACIONESArizona Geological Survey
ORCID0000-0002-7165-0743
VERIFICADOSí
TOTAL DE OBRAS33
TOTAL DE CITAS87
TOTAL COMO AUTOR32
TOTAL COMO EDITOR1
PRIMER AÑO DE PUBLICACIÓN1984
AÑO MÁS RECIENTE DE PUBLICACIÓN2026
ÍNDICE H3

  • A 40,000-year packrat midden series from Cataviña, central Baja California, Mexico

    Open AccessJulio L Betancourt, Julio Betancourt et al.ARTICLEQuaternary Research2026

    Thirty packrat ( Neotoma spp.) middens collected from boulder fields near Cataviña, Baja California, Mexico, at 640–680 m elevation provide the first long chronology of macrofossils and pollen spanning the late Quaternary in the Central Desert of Baja California. Midden plant macrofossil and pollen assemblages document a rich chaparral/woodland assemblage during the last glacial and early Holocene dominated by Parry pinyon ( Pinus quadrifolia ) a…

  • Transporting Timbers to Chaco Canyon

    James A Wilson, R S Weiner et al.ARTICLEKIVA2023Citada por: 1Referencias: 26

    A total of 200,000+ large timbers were transported >75 km to Chaco Canyon, a political and religious center in the precontact U.S. Southwest, using only human power. Previous researchers reported that typical primary roof beams (vigas) of Chacoan Great Houses averaged 0.22 m in diameter and 5 m in length with a mass of 275 kg. However, the 275 kg mass appears to be a miscalculation. Here, we calculate that a ponderosa pine timber of the stated di…

  • Packrat Middens

    Julio L Betancourt, Thomas R Van Devender et al.BOOKPackrat Middens2021

  • The Spatial and Temporal Distribution of Radiocarbon Ages from Packrat Middens

    Robert H Webb, Julio L BetancourtCHAPTERPackrat Middens2021

  • Unfamiliar Territory

    Open AccessShelley D Crausbay, Julio L Betancourt et al.ARTICLEOne Earth2020

    Novel forms of drought are emerging globally, due to climate change, shifting teleconnection patterns, expanding human water use, and a history of human influence on the environment that increases the probability of transformational ecological impacts. These costly ecological impacts cascade to human communities, and understanding this changing drought landscape is one of today's grand challenges. By using a modified horizon-scanning approach tha…

  • Investigating (a)symmetry in a small mammal's response to warming and cooling events across western North America over the late Quaternary

    Open AccessMeghan A Balk, Julio L Betancourt et al.ARTICLEQuaternary Research2019

    Many mammalian populations conform spatially and temporally to Bergmann's rule. This ecogeographic pattern is driven by selection for larger body masses by cooler temperatures and smaller ones by warming temperatures. However, it is unclear whether the response to warming or cooling temperatures is (a)symmetrical. Studies of the evolutionary record suggest that mammals evolve smaller body sizes more rapidly than larger ones, suggesting that it ma…

  • The Neotoma Paleoecology Database, a multiproxy, international, community-curated data resource

    Open AccessJohn W Williams, Eric C Grimm et al.ARTICLEQuaternary Research2018

    The Neotoma Paleoecology Database is a community-curated data resource that supports interdisciplinary global change research by enabling broad-scale studies of taxon and community diversity, distributions, and dynamics during the large environmental changes of the past. By consolidating many kinds of data into a common repository, Neotoma lowers costs of paleodata management, makes paleoecological data openly available, and offers a high-quality…

  • Reduced Population Variance in Strontium Isotope Ratios Informs Domesticated Turkey Use at Chaco Canyon, New Mexico, USA

    Open AccessDeanna N Grimstead, Amanda C Reynolds et al.ARTICLEJournal of Archaeological Method…2014Citada por: 13Referencias: 12

  • Holocene fire occurrence and alluvial responses at the leading edge of pinyon–juniper migration in the Northern Great Basin, USA

    Open AccessKerrie N Weppner, Kerrie Weppner et al.ARTICLEQuaternary Research2013

    Fire and vegetation records at the City of Rocks National Reserve (CIRO), south-central Idaho, display the interaction of changing climate, fire and vegetation along the migrating front of single-leaf pinyon ( Pinus monophylla ) and Utah juniper ( Juniperus osteosperma ). Radiocarbon dating of alluvial charcoal reconstructed local fire occurrence and geomorphic response, and fossil woodrat ( Neotoma ) middens revealed pinyon and juniper arrivals.…

  • Long-term snowpack variability and change in the North American cordillera

    Open AccessGregory T Pederson, Stephen T Gray et al.ARTICLEQuaternary International2013

  • Vegetation history along the eastern, desert escarpment of the Sierra San Pedro Mártir, Baja California, Mexico

    Open AccessCamille A Holmgren, Julio L Betancourt et al.ARTICLEQuaternary Research2011

    Plant macrofossils from 38 packrat middens spanning the last ~ 33,000 cal yr BP record vegetation between ~ 650 and 900 m elevation along the eastern escarpment of the Sierra San Pedro Mártir, northern Baja California. The middens span most of the Holocene, with a gap between ~ 4600 and 1800 cal yr BP, but coverage in the Pleistocene is uneven with a larger hiatus between 23,100 and 14,400 cal yr BP. The midden flora is relatively stable from the…

  • Paleowetlands and regional climate change in the central Atacama Desert, northern chile

    Open AccessJay Quade, Jason A Rech et al.ARTICLEQuaternary Research2008

    Widespread, organic-rich diatomaceous deposits are evidence for formerly wetter times along the margins of the central Atacama Desert, one of the driest places on Earth today. We mapped and dated these paleowetland deposits at three presently waterless locations near Salar de Punta Negra (24.5°S) on the western slope of the Andes. Elevated groundwater levels supported phreatic discharge into wetlands during two periods: 15,900 to ~ 13,800 and 12,…

  • Stationarity Is Dead

    Open AccessP C D Milly, Julio L Betancourt et al.ARTICLEScience2008

    Climate change undermines a basic assumption that historically has facilitated management of water supplies, demands, and risks.

  • Associations of multi-decadal sea-surface temperature variability with US drought

    Open AccessGregory J McCabe, Julio L Betancourt et al.ARTICLEQuaternary International2008

  • Annual precipitation in the yellowstone National Park region since AD 1173

    Open AccessStephen T Gray, Lisa J Graumlich et al.ARTICLEQuaternary Research2007

    Cores and cross sections from 133 limber pine ( Pinus flexilis James) and Douglas fir ( Pseudotsuga menziesii (Mirbel) Franco) at four sites were used to estimate annual (July to June) precipitation in the Yellowstone National Park region for the period from AD 1173 to 1998. Examination of the long-term record shows that the early 20th century was markedly wet compared to the previous 700 yr. Extreme wet and dry years within the instrumental peri…

  • Late Quaternary vegetation and climate history of a perennial river canyon in the Río Salado basin (22°S) of Northern Chile

    Open AccessClaudio Latorre, Julio L Betancourt et al.ARTICLEQuaternary Research2006

    Plant macrofossils from 33 rodent middens sampled at three sites between 2910 and 3150 m elevation in the main canyon of the Río Salado, northern Chile, yield a unique record of vegetation and climate over the past 22,000 cal yr BP. Presence of low-elevation Prepuna taxa throughout the record suggests that mean annual temperature never cooled by more than 5°C and may have been near-modern at 16,270 cal yr BP. Displacements in the lower limits of …

  • Sr/86Sr sourcing of ponderosa pine used in Anasazi great house construction at Chaco Canyon, New Mexico

    Open AccessAmanda C Reynolds, Julio L Betancourt et al.ARTICLEJournal of Archaeological Science2005Citada por: 35Referencias: 3

  • Phylogeny, diet, and habitat of an extinct ground sloth from Cuchillo Curá, Neuquén Province, southwest Argentina

    Open AccessMichael Hofreiter, Julio L Betancourt et al.ARTICLEQuaternary Research2003

    Advancements in ancient DNA analyses now permit comparative molecular and morphological studies of extinct animal dung commonly preserved in caves of semiarid regions. These new techniques are showcased using a unique dung deposit preserved in a late glacial vizcacha ( Lagidium sp.) midden from a limestone cave in southwestern Argentina (38.5° S). Phylogenetic analyses of the mitochondrial DNA show that the dung originated from a small ground slo…

  • The effect of Holocene temperature fluctuations on the evolution and ecology of Neotoma (woodrats) in Idaho and northwestern Utah

    Open AccessFelicia A Smith, Felisa A Smith et al.ARTICLEQuaternary Research2003

    Animals respond to climatic change by adapting or by altering distributional patterns. How an animal responds is influenced by where it is positioned within its geographic range; the probability of extirpation is increased near range boundaries. Here, we examine the impact of Holocene climatic fluctuations on a small mammalian herbivore, the bushy-tailed woodrat ( Neotoma cinerea ), at five locations within south central Idaho and northwestern Ut…

  • Holocene Vegetation and Climate History of the Northern Bighorn Basin, Southern Montana

    Open AccessMark E Lyford, Julio L Betancourt et al.ARTICLEQuaternary Research2002

    Records of Holocene vegetation and climate change at low elevations ( 14 C-dated woodrat middens at two low-elevation sites (1275 to 1590 m), currently vegetated by Juniperus osteosperma woodlands, in the northern Bighorn Basin. Macrofossil and pollen analyses show that the early Holocene was cooler than today, with warming and drying in the middle Holocene. During the Holocene, boreal ( Juniperus communis, J. horizontalis ) and montane species (…

  • A Test of “Annual Resolution” in Stalagmites Using Tree Rings

    Open AccessJulio L Betancourt, Henri D Grissino‐Mayer et al.ARTICLEQuaternary Research2002

    So-called annual banding has been identified in a number of speleothems in which the number of bands approximates the time interval between successive U-series dates. The apparent annual resolution of speleothem records, however, remains largely untested. Here we statistically compare variations in band thickness from a late Holocene stalagmite in Carlsbad Cavern, Southern New Mexico, USA, with three independent tree-ring chronologies form the sa…

  • Holocene Lake-Level Fluctuations of Lake Aricota, Southern Peru

    Open AccessChrista Placzek, Jay Quade et al.ARTICLEQuaternary Research2001

    Lacustrine deposits exposed around Lake Aricota, Peru (17° 22′S), a 7.5-km 2 lake dammed by debris flows, provide a middle to late Holocene record of lake-level fluctuations. Chronological context for shoreline deposits was obtained from radiocarbon dating of vascular plant remains and other datable material with minimal 14 C reservoir effects ( 14 C yr B.P. and ended ∼2700 14 C yr B.P. Moderately high lake levels occurred at 1700 and 1300 14 C y…

  • Holocene Vegetation History from Fossil Rodent Middens near Arequipa, Peru

    Open AccessCamille A Holmgren, Julio L Betancourt et al.ARTICLEQuaternary Research2001

    Rodent ( Abrocoma, Lagidium, Phyllotis ) middens collected from 2350 to 2750 m elevation near Arequipa, Peru (16°S), provide an ∼9600-yr vegetation history of the northern Atacama Desert, based on identification of >50 species of plant macrofossils. These midden floras show considerable stability throughout the Holocene, with slightly more mesophytic plant assemblages in the middle Holocene. Unlike the southwestern United States, rodent middens o…

  • Strontium isotopes reveal distant sources of architectural timber in Chaco Canyon, New Mexico

    Open AccessNathan B English, Julio L Betancourt et al.ARTICLEProceedings of the National…2001

    Between A.D. 900 and 1150, more than 200,000 conifer trees were used to build the prehistoric great houses of Chaco Canyon, New Mexico, in what is now a treeless landscape. More than one-fifth of these timbers were spruce ( Picea ) or fir ( Abies ) that were hand-carried from isolated mountaintops 75–100 km away. Because strontium from local dust, water, and underlying bedrock is incorporated by trees, specific logging sites can be identified by …

  • A History of Mescalero Apache - U.S. Army Encounters in Dog Canyon, New Mexico

    Julio L Betancourt