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P.H. Jones

Publications and source records attributed to P.H. Jones.

5 recordsLinked to original sources
USGS2011

Deltamethrin flea-control preserves genetic variability of black-tailed prairie dogs during a plague outbreak

Genetic variability and structure of nine black-tailed prairie dog (BTPD, Cynomys ludovicianus ) colonies were estimated with 15 unlinked microsatellite markers. A plague epizootic occurred between the first and second years of sampling and our study colonies were nearly extirpated with the exception of three colonies in which prairie dog burrows were previously dusted with an insecticide, deltamethrin, used to control fleas (vectors of the causative agent of plague, Yersinia pestis ). This situation provided context to compare genetic variability and structure among dusted and non-dusted colonies pre-epizootic, and among the three dusted colonies pre- and post-epizootic. We found no statistical difference in population genetic structures between dusted and non-dusted colonies pre-epizootic. On dusted colonies, gene flow and recent migration rates increased from the first (pre-epizootic) year to the second (post-epizootic) year which suggested dusted colonies were acting as refugia for prairie dogs from surrounding colonies impacted by plague. Indeed, in the dusted colonies, estimated densities of adult prairie dogs (including dispersers), but not juveniles (non-dispersers), increased from the first year to the second year. In addition to preserving BTPDs and many species that depend on them, protecting colonies with deltamethrin or a plague vaccine could be an effective method to preserve genetic variability of prairie dogs.

Montana↗
USGS1970

Geothermal resources of the northern gulf of Mexico basin

Published geothermal gradient maps for the northern Gulf of Mexico basin indicate little or no potential for the development of geothermal resources. Results of deep drilling, from 4000 to 7000 meters or more, during the past decade however, define very sharp increases in geothermal gradient which are associated with the occurrence of abnormally high interstitial fluid pressure (geopressure). Bounded by regional growth faults along the landward margin of the Gulf Basin, the geopressured zone extends some 1300 km from the Rio Grande (at the boundary between the United States and Mexico) to the mouth of the Mississippi river. Gulfward, it extends to an unknown distance across the Continental Shelf. Within geopressured deposits, geothermal gradients range upwards to 100 °C/km, being greatest within and immediately below the depth interval in which the maximum pressure gradient change occurs. The 120 °C isogeotherm ranges from about 2500 to 5000 m below sea level, and conforms in a general way with depth of occurrence of the top of the geopressured zone. Measured geostatic ratios range upward to 0.97; the maximum observed temperature is 273 °C, at a depth of 5859 m. Dehydration of montmorillonite, which comprises 60 to 80 percent of clay deposited in the northern Gulf Basin during the Neogene, occurs at depths where temperature exceeds about 80 °C, and is generally complete at depths where temperature exceeds 120 °C. This process converts intracrystalline and bound water to free pore water, the volume produced being roughly equivalent to half the volume of montmorillonite so altered. Produced water is fresh, and has low viscosity and density. Sand-bed aquifers of deltaic, longshore, or marine origin form excellent avenues for drainage of geopressured deposits by wells, each of which may yield 10,000 m 3 or more of superheated water per day from reservoirs having pressures up to 1000 bars at depths greater than 5000 m.

Louisiana, Texas↗
USGS1961

Ground-water control in the Neyveli lignite field, South Arcot district, Madras State, India

Unconsolidated deposits of the Cuddalore series of Miocene age underlie much of the coastal plain of southern Madras . Several lignite seams occur in a thick sequence of sand, gravel, and clay that dips seaward about 40 to 100 feet per mile. The principal seam of lignite mapped in the Neyveli area averages more than 50 feet in thickness, underlies at least 80 square miles, and occurs at a minimum depth of 165 feet near Neyveli , where deposits totalling 230 million tons have been proved in an area of 4J square miles. The lignite seam is immediately underlain, throughout its area of occurrence, by a thick bed of sand and gravel that contains artesian water, the head of which is more than 100 feet above the top of the lignite at Neyveli . The sand and gravel aquifer is exposed to recharge in and near its outcrop area, 6 to 10 miles northwest of Neyveli , where the average annual rainfall is 41 inches. Hydraulic tests of the aquifer indicate that ground-water control for mining by opencast from a pit 6,000 feet long and 1,200 feet wide will require continuous withdrawal of about 40,000 gallons (Imperial) per minute from wells in and adjacent to the mine. The well field , including 50 to 65 large-capacity wells, must move with the open cut; and no appreciable decrease in the withdrawal rate can be expected throughout the life of the mine, which is designed to produce about 3j million tons of raw lignite per year.

Madras State↗