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dc.contributor.authorBryan-Ricketts, Debra
dc.date.accessioned2012-07-03T17:03:34Z
dc.date.available2014-05-14T10:00:08Z
dc.date.issued2012-07-03
dc.date.submittedMay 2012
dc.identifier.urihttp://hdl.handle.net/1928/20808
dc.description.abstractSoils in the arid to semi-arid piedmont landscapes of central New Mexico were examined in order to evaluate surficial processes and landscape evolution in the central Rio Grande Rift. These soils were found to contain key information regarding pedologic and geomorphic responses to climate change, rifting and base level drop. A rare association of sepiolite and palygorskite occurs in old soils formed in eolian fines. Pedologic and mineralogical data indicate that palygorskite formed by transformation of dust-borne, aluminum-rich minerals, and that sepiolite subsequently formed by transformation of palygorskite. The association of these two minerals, and geomorphic observations, confirm the existence of a 1 – 3.5 Ma abandoned geomorphic surface of the ancestral Rio Grande. In contrast to Mormon Mesa, Nevada, and Ogallala Formation paleosols, massive cementation by pedogenic carbonate, and chaotic pedogenic carbonate pendants are notably absent in soils formed on the 1 – 3.5 Ma surface. It is hypothesized that abandonment of geomorphic surfaces, largely due to down-cutting by the ancestral Rio Grande, and slow accumulation of fine eolian sediments resulted in the absence of well-developed petrocalcic soil properties usually observed in soils of this age. Other geomorphic observations confirm the hypothesis of an ancestral Palo Duro drainage in the McKensie Flats Basin. In contrast to monogenetic soils, only one polygenetic soil demonstrates stable carbon isotope depth trends similar to the diffusion model of Cerling et al. (1989). Low delta 13C carbonate values in the near-surface reflect the introduction of exogenous material. Low delta 13C carbonate values at >50 cm of depth reflect buried rooting zones of plant assemblages that occurred in the past. An association between buried soil boundaries and shifts in delta 13C carbonate depth trends indicates that changes in C3 and C4 plant assemblages have occurred in the past. These shifts may reflect paleo-environmental conditions present when the soils formed, over-printing of Holocene paleo-environmental conditions onto older soils, or “time-averaged” combinations of both records. Microtopography, soil grain size, induration, and surface clast cover potentially influence the distributions of Larrea tridentata, Bouteloua gracilis, and Bouteloua eriopoda. However, distributions of these species were not affected by lithology, soil age, soil salinity, or high soil pH.en_US
dc.description.sponsorshipThis research was partially supported by an NSF grant to the University of New Mexico for Long-term Ecological Research, and by the US Fish and Wildlife Service, Sevilleta National Wildlife Refuge, and Los Alamos National Laboratory (LA-UR 12-00618).en_US
dc.language.isoen_USen_US
dc.subjectsepioliteen_US
dc.subjectpalygorskiteen_US
dc.subjectSevilleta Long Term Ecological Research Siteen_US
dc.subjectRio Grande Riften_US
dc.subjectpedogenic carbonateen_US
dc.subjectstable carbon isotopesen_US
dc.subjectstable oxygen isotopesen_US
dc.subjectcalcic soilsen_US
dc.subjectsoil pisolithsen_US
dc.subjectpetrocalcicen_US
dc.subjectpetrogypsicen_US
dc.subjectsoil carbonateen_US
dc.subject.lcshPaleopedology--New Mexico--Sevilleta National Wildlife Refuge.
dc.subject.lcshPaleogeography--New Mexico--Sevilleta National Wildlife Refuge.
dc.subject.lcshSoils--New Mexico--Sevilleta National Wildlife Refuge.
dc.subject.lcshGeomorphology--New Mexico--Sevilleta National Wildlife Refuge.
dc.subject.lcshRio Grande Rift.
dc.titleSoil geomorphology of the eastern Sevilleta Long Term Ecological Research Siteen_US
dc.typeDissertationen_US
dc.description.degreeEarth and Planetary Sciencesen_US
dc.description.levelDoctoralen_US
dc.description.departmentUniversity of New Mexico. Dept. of Earth and Planetary Sciencesen_US
dc.description.advisorMcFadden, Leslie
dc.description.committee-memberMeyer, Grant
dc.description.committee-memberMoore, Duane
dc.description.committee-memberSharp, Zachary
dc.description.committee-memberCollins, Scott
emb.embargo.terms2014-05-14


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