LATE QUATERNARY ECOLOGY, CLIMATOLOGY, AND BIOGEOGRAPHY OF THE NORTHERN CHIHUAHUAN DESERT FROM FOSSIL PACKRAT MIDDENS

Persistent Link:
http://hdl.handle.net/10150/196087
Title:
LATE QUATERNARY ECOLOGY, CLIMATOLOGY, AND BIOGEOGRAPHY OF THE NORTHERN CHIHUAHUAN DESERT FROM FOSSIL PACKRAT MIDDENS
Author:
Holmgren, Camille Ann
Issue Date:
2005
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
The northwestern Chihuahuan Desert along the U.S.A.-Mexico border contains a rich mosaic of vegetation with high levels of biodiversity. A conspicuous gap in packrat midden coverage, however, exists for this area and paleovegetation data is scarce. The focus of this dissertation is the reconstruction of late Quaternary ecology, climatology, and biogeography of the northern Chihuahuan Desert.A new packrat midden chronology from Playas Valley, NM is the first installment of an effort to reconstruct paleovegetation and paleoclimate in the U.S.A.-Mexico Borderlands. Plant macrofossil and pollen assemblages from nine middens indicate late Pleistocene vegetation along pluvial lake margins consisted of open pinyon-juniper communities dominated by Pinus edulis, Juniperus scopulorum, Juniperus cf. coahuilensis and an understory of C4 annuals and grasses. This summer-flowering understory, characteristic of modern desert grasslands, suggests at least moderate late Pleistocene summer precipitation. By 10,670 14C yr B.P. Pinus edulis and Juniperus scopulorum had become rare or disappeared. The late Holocene was marked by arrival of Chihuahuan Desert scrub as vegetation became modern in character. A 36,200 cal yr B.P. midden record was also developed from the Peloncillo Mountains along the Arizona-New Mexico-Mexico border. Between 36,200-15,410 cal yr B.P., rocky areas above playa lakes supported Pinus edulis, Juniperus osteosperma, Juniperus cf. coahuilensis, and Quercus turbinella. This site also supported summer-flowering C4 annuals and grasses, indicating abundant summer rains and relatively warm temperatures. After ~15,410 cal yr B.P., Pinus edulis declined in abundance and disappeared briefly at 13,925 cal yr B.P., coincident with other evidence for Bølling-Allerød aridity, and then rebounded briefly during the Younger Dryas. Few middens date from the early to middle Holocene, while 35 middens from the late Holocene detail increasingly aridity.Bioclimatic envelopes were also applied to packrat midden series from the USA-Mexico borderlands. Bioclimatic envelopes for C4 grasses indicate winter temperatures were no more than 4.5ºC colder than present and summer temperatures no more than 4.4ºC colder during late Pleistocene, while summer precipitation was reduced by no more than 50%. The appearance of many desertscrub species around 5000-4000 yr B.P. appears to have been due, at least in part, to increasing winter temperatures.
Type:
text; Electronic Dissertation
Keywords:
Geosciences
Degree Name:
DA
Degree Level:
doctoral
Degree Program:
Geosciences; Graduate College
Degree Grantor:
University of Arizona
Advisor:
Quade, Jay
Committee Chair:
Quade, Jay

Full metadata record

DC FieldValue Language
dc.language.isoENen_US
dc.titleLATE QUATERNARY ECOLOGY, CLIMATOLOGY, AND BIOGEOGRAPHY OF THE NORTHERN CHIHUAHUAN DESERT FROM FOSSIL PACKRAT MIDDENSen_US
dc.creatorHolmgren, Camille Annen_US
dc.contributor.authorHolmgren, Camille Annen_US
dc.date.issued2005en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractThe northwestern Chihuahuan Desert along the U.S.A.-Mexico border contains a rich mosaic of vegetation with high levels of biodiversity. A conspicuous gap in packrat midden coverage, however, exists for this area and paleovegetation data is scarce. The focus of this dissertation is the reconstruction of late Quaternary ecology, climatology, and biogeography of the northern Chihuahuan Desert.A new packrat midden chronology from Playas Valley, NM is the first installment of an effort to reconstruct paleovegetation and paleoclimate in the U.S.A.-Mexico Borderlands. Plant macrofossil and pollen assemblages from nine middens indicate late Pleistocene vegetation along pluvial lake margins consisted of open pinyon-juniper communities dominated by Pinus edulis, Juniperus scopulorum, Juniperus cf. coahuilensis and an understory of C4 annuals and grasses. This summer-flowering understory, characteristic of modern desert grasslands, suggests at least moderate late Pleistocene summer precipitation. By 10,670 14C yr B.P. Pinus edulis and Juniperus scopulorum had become rare or disappeared. The late Holocene was marked by arrival of Chihuahuan Desert scrub as vegetation became modern in character. A 36,200 cal yr B.P. midden record was also developed from the Peloncillo Mountains along the Arizona-New Mexico-Mexico border. Between 36,200-15,410 cal yr B.P., rocky areas above playa lakes supported Pinus edulis, Juniperus osteosperma, Juniperus cf. coahuilensis, and Quercus turbinella. This site also supported summer-flowering C4 annuals and grasses, indicating abundant summer rains and relatively warm temperatures. After ~15,410 cal yr B.P., Pinus edulis declined in abundance and disappeared briefly at 13,925 cal yr B.P., coincident with other evidence for Bølling-Allerød aridity, and then rebounded briefly during the Younger Dryas. Few middens date from the early to middle Holocene, while 35 middens from the late Holocene detail increasingly aridity.Bioclimatic envelopes were also applied to packrat midden series from the USA-Mexico borderlands. Bioclimatic envelopes for C4 grasses indicate winter temperatures were no more than 4.5ºC colder than present and summer temperatures no more than 4.4ºC colder during late Pleistocene, while summer precipitation was reduced by no more than 50%. The appearance of many desertscrub species around 5000-4000 yr B.P. appears to have been due, at least in part, to increasing winter temperatures.en_US
dc.typetexten_US
dc.typeElectronic Dissertationen_US
dc.subjectGeosciencesen_US
thesis.degree.nameDAen_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineGeosciencesen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorQuade, Jayen_US
dc.contributor.chairQuade, Jayen_US
dc.contributor.committeememberBetancourt, Julio L.en_US
dc.contributor.committeememberCole, Julieen_US
dc.contributor.committeememberComrie, Andrewen_US
dc.contributor.committeememberOverpeck, Jonathanen_US
dc.identifier.proquest1191en_US
dc.identifier.oclc137354295en_US
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