No description available.

No description available.

No description available.

Three aquifers of diverse lithology and hydraulic character form the ground-water reservoir in the Roswell basin. The main aquifer, the carbonate aquifer, is developed in carbonate rocks of Permian age. It is the source of about two-thirds of the ground water pumped in the basin and receives more than 90 percent of the recharge to the basin. The second most important aquifer is the shallow aquifer which lies near the Pecos River in beds of sand and gravel of both Permian and Holocene age. About one-third of the ground water pumped in the basin comes from the shallow aquifer. Prior to pumping, the main source of recharge to the shallow aquifer was probably ground water leaking upward from the carbonate aquifer. Since pumping began, the main source of recharge to the shallow aquifer is probably return flow of irrigation water pumped from the carbonate aquifer. Natural discharge of ground water from the shallow aquifer into the Pecos River causes a gain in th.e base flow of the Pecos River in the Roswell basin. The third aquifer, the shallow-artesian aquifer, is in red beds and evaporite beds of Permian age. This aquifer overlies the carbonate aquifer and underlies the shallow aquifer. The shallow-artesian aquifer acts as a minor aquifer and also as a semi-permeable unit which partly confines ground water in the carbonate aquifer. Vertical permeability of the shallow-artesian aquifer is variable and depends on the lithology and thickness of the aquifer. Hydraulic head in the shallow-artesian aquifer also varies quite widely depending on the depth to which a well penetrates the aquifer. All ground-water aquifers in the basin transect formational boundaries and are therefore not closely related to the named geologic formations. A flow net analysis of the carbonate aquifer and of the shallow aquifer imply that geologic structure is important in the movement of ground water in the basin by limiting the transmissivity of the shallow and carbonate aquifers, by forming the present pattern of surface water drainage, and possibly by the contamination of fresh ground water by highly saline ground water. The flow net analysis also shows areas of recharge to the shallow and carbonate aquifers, and areas where the carbonate aquifer looses water to the shallow-artesian aquifer and to the shallow aquifer.

No description available.

No description available.

Wooden beams and planks from the Spanish Colonial church and other structures in Las Trampas, north-central New Mexico, have been sampled and dated by dendrochronology. Dates of AD 1735 imply Spanish occupation of the area 16 years prior to official grant. Stockpiling of timber for church construction began as early as 1758. Exterior walls were 15 feet high by 1762 and were completed to roof level by 1764. Late in 1776, wood was cut for a dust-guard over the adobe altar and mural. According to clustering of tree-ring dates, a new altar and wooden altar screen were constructed soon after 1785. Beam re-use was prevalent. Timbers bearing early dates were incorporated into the 1785 altar screen, indicating re-use from within the church or from other pre-1760 structures. A roof viga was later used as a floor plank after reroofing. In domestic buildings, re-use of beams is repeated. Replacement of beams supporting the balcony was made in the 1860's and 1870's. Tree-ring dates indicate repairs again in the 1930's and 1943. A survey of the literature pertaining to dendrochronology of historical sites revealed that shaping of beams and lack of thorough sampling have heretofore hindered successful application. The documentary record of Las Trampas art and architectural history has been further refined by tree -ring dating, and the study reaffirms the potentials for historical sites dendrochronology.

No description available.

No description available.

The primary factors that influence stratigraphy are tectonic subsidence, eustasy, and sediment supply. Change in any of these factors potentially produces a similar response in the form of a change in accommodation space. Accordingly, distinguishing the origin of a stratigraphic response is difficult, but theoretically possible by analysis of temporal and spatial extents of the accommodation signal. Correlation is critical for distinguishing eustasy from tectonism. Upper Pennsylvanian strata of the Pedregosa and Orogrande basins (southern Ancestral Rocky Mountains) were deposited during a time of continental collision and extensive continental glaciation, and contain a composite record of changing tectonism, eustasy, climate, and sediment supply. High-frequency stratigraphic cyclicity expressed as repetitive stacks of lithofacies at the scale of 10¹ m pervades all sections and displays features that collectively imply a primary glacioeustatic origin, notably: (1) abrupt juxtaposition of dissimilar lithofacies, signaling a rapid rate of baselevel change, (2) apparent intrabasinal, interbasinal and, provisionally, interregional correlation of high-frequency cycles across and between contrasting tectonic environments, and (3) cycle frequencies that approach the 413 ka periodicity of orbital eccentricity, the probable forcing mechanism for Pennsylvanian glaciations. Glacial-interglacial climate change expressed as precipitation and circulation fluctuations in the equatorial Pedregosa and Orogrande basins accompanied Pennsylvanian glacioeustasy. Intensified aridity and wind strength during peak glacials led to decreased fluvio-deltaic sedimentation and increased eolian activity where siliciclastics were available. Conversely, increased precipitation during interglacials reactivated and/or intensified fluvio-deltaic sediment yield. Eustasy dictated fluvial aggradation versus degradation and coastal sediment trapping versus bypassing. Coupled glacioeustatic-glacioclimatic change was sufficiently severe to reconfigure environments between climatic extremes, which implies that Pennsylvanian stratigraphic cycles should be viewed in at least partially non-Waltherian terms. Each cycle potentially recorded contrasting facies mosaics that were to some degree temporally exclusive. Multiple-cycle trends in facies and/or thickness also occur to define low-frequency stratigraphic patterns at the scale of 10² m. Qualitative analysis of these trends implicates distinct eustatic and tectonic processes as contributing influences. The eustatic component may derive from low-frequency glacioeustasy as well as tectonoeustasy related to evolving continental paleogeography. The tectonic component probably reflects late Paleozoic Marathon-Ouachita collisional orogenesis.