Douglas G. Mose

Geochemical evidence for a revised Precambrian sequence in the northwest Adirondacks, New York

Middle Proterozoic metasedimentary and metavolcanic rocks in the northwest Adirondacks are assigned into four lithostratigraphic units: basal Hyde School Gneiss that herein is given formational status, lower marble, Popple Hill Gneiss Formation, and upper marble. A variety of stratigraphic columns have been proposed for this complexly deformed terrane, the most recent being a column by Wiener and others (1984). Their basal formation, the Alexandria Bay Gneiss, is defined from rocks that include the Rockport granite gneiss near Rockport, Ontario, and Alexandria Bay, New York, as well as leucogneisses in 14 structural domes throughout the northwest Adirondacks. We believe that these rocks have a diverse origin, one being intrusive, the other volcanic ash. Their uppermost formation, the Pleasant Lake Gneiss, includes granitoid gneisses near Rossie village and Pleasant Lake that they suggest are illitic arkoses, but we give field, geochemical, and geochronological evidence for an intrusive origin. The gneisses near Rossie village have a whole-rock Rb-Sr age of 1,160±42 m.y. (IR = 0.7036 ± 0.0004), and similar gneisses near Antwerp village are 1,197 ± 53 m.y. (IR = 0.7034 ± 0.0005). These ages are younger than the zircon U-Pb ages of 1,280-1,250 m.y. generally obtained for metasedimentary and metavolcanic rocks in the Central Metasedimentary Belt of Ontario. We urge abandonment of the five formations and two Groups proposed by Wiener and others (1984) on the basis of an intrusive origin for the gneisses near Rockport and Rossie villages and on stratigraphic correlations of recent studies. The stratigraphy of four formations proposed herein with a generalized geologic map of the northwest Adirondacks may lead to correlation with carbonate sequences in the Central Metasedimentary Belt and with rocks of the Adirondack highlands to the east.

Reliability of inexpensive charcoal and alpha-track radon monitors

A comparison between single short-term radon measurements and annual radon measurements in basements shows that significant uncertainties should be associated with the short-term measurements. Activated charcoal radon monitors which measure radon over a 3 to 7 day interval yield measurements that should carry a ± 90% uncertainty in terms of estimating annual radon concentration. Alpha-track radon monitors which measure radon over a 3 month interval should carry a ± 30% uncertainty. Decisions about home purchases, home remediation and the development of risk characterizations may often be incorrect if currently popular but unrealistically low estimates of uncertainty are applied to short-term radon measurements. Optimal results are obtained from year-long alpha-track measurements.

Soil radon, permeability, and indoor radon prediction

Attempts to predict which geographic areas should be associated with a high percentage of homes with unusually high indoor radon levels have been based on estimates of soil radon and soil permeability for geological units. In northern Virginia and southern Maryland, it appears that predictions of indoor radon based on estimates of homesite soil radon and soil permeability are very useful.

Radioactive hazard of potable water in Virginia and Maryland

Only a few studies have examined instances of prolonged exposure to radionuclide concentrations found in natural settings. Radium in domestic water in Florida counties has been correlated with a higher than normal incidence of leukemia. A similar study in Iowa towns reported on a correlation between radium and increases in lung, bladder and breast cancer. Radium and radon in domestic water has been correlated with the development of lung cancer in a study of several Texas counties. A correlation has been found between radon in home water supplies in Maine and the incidence of lung cancer. Starting in the winter of 1986-87, the Center of Basic and Applied Science conducted a study of indoor radon and soil radon. Most of the study homes are in Fairfax County in northern Virginia, and the immediately adjacent Montgomery County in southern Maryland. Approximately 650 homeowners agreed to participate in the radon-in-water study. The study group now includes approximately 1,400 people, over 1,000 of whom have consumed their present water supply for 5 or more years, and over 700 of whom have consumed this water for 10 or more years.

Regional levels of indoor radon in Virginia and Maryland

The levels of Rn-222 in homes located in Fairfax County, Virginia, and Montgomery County, Maryland, are currently being measured during four consecutive three-month seasonal intervals using alpha-track detectors. Significant variations occur between parts of northern Virginia and southern Maryland because the area is part of three very different geologic provinces. Results from the winter period in these three provinces show that the indoor radon levels were about twice as high as anticipated. Approximately 45 percent of the homes had winter indoor radon levels above 4 pCi/l, the EPA’s recommended action level, and in the spring period, more than 30 percent of the homes still had indoor levels above 4 pCi/l. Indoor radon variations due to seasonal control were about as significant as geological control. Worst-case combinations developed over some rock units in the winter, producing areas in which about 70 percent of the homes exceeded 4 pCi/l.

The effect of home construction on indoor radon in Virginia and Maryland

Abstract The levels of indoor radon in approximately 500 homes located in two contiguous counties of northern Virginia and southern Maryland have been measured during four consecutive, three month seasonal intervals using alpha-track detectors. These two counties represent an area of about 700 square miles. Results from the winter period show that the indoor radon levels were about twice as high as anticipated. In some areas, more than 50% of the homes had winter indoor radon levels above 4 pCi/liter, the EPAs recommended action level. For the spring and fall periods, indoor radon levels showed a considerable drop with approximately 35% of the homes above 4 pCi/L. Summer values were even lower with approximately 25% of the homes above 4 pCi/L. Indoor radon can be related to the weather, but home construction demonstrably determines indoor radon levels.

Liquid phase oxidation of organo-sulfur compounds by tert-butyl hydroperoxide and fuel instability reactions

Abstract Polar heteroatomic species have been correlated with storage instability problems in both petroleum and shale derived middle distillate fuels. Instability is defined as the formation of filterable sediments and fuel insoluble gums. Heteroatoms (oxygen, nitrogen and sulfur) have been found to be greatly enhanced in such sediments. Trace levels of certain organo-sulfur compounds, especially sulfonic acids, have been found to significantly alter the deposit formation process. Hydroperoxides have also been implicated in the instability process which would point to free radical mechanisms. The effectiveness of organic amines as additives suggests that acid-base chemistry is also involved in the formation of deposits. This paper reports on a study of organo-sulfur, nitrogen and hydroperoxide compounds employed as dopants in fuels. The most detrimental dopant species were sulfonic acids.

Winter‐to‐winter variations in indoor radon

Indoor radon concentrations in northern Virginia and central Maryland show a strong dependence on weather. Winter tends to be associated with higher than average indoor radon, and summer with lower than average. However, compared to the winter of 1986-1987, the winter of 1987-1988 was warmer and drier. Consequently, winter-to-winter indoor radon decreased by about 25%. This winter-to-winter decrease is unexpectedly large, and simulates winter-to-summer variations that have been reported.

1,300-million-year-old rocks in the Appalachians

Studies using radiometric age determinations on Precambrian rocks in the Appalachians have located rocks that are more than 1,000 m.y. old. A Rb-Sr whole-rock isochron study of granitic gneiss in the Manhattan Prong of southeastern New York shows that this rock is at least 1,350 m.y. old. Rb-Sr data also show that this granitic gneiss developed strontium isotopic homogenization over outcrop-sized volumes (10 m in diam) at about 1,100 m.y. ago.

Prediction of indoor radon by aeroradioactivity

Attempts to predict which geographic areas should be associated with a high percentage of homes with unusually high indoor radon levels in Virginia and Maryland have been based on estimates of soil radon and soil permeability for geological units. This method is found to be less successful and probably less cost-effective than the use of total-gamma aeroradioactivity maps.