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Meyer Rubin

Publications and source records attributed to Meyer Rubin.

At least 19 recordsLinked to original sources
USGS2010

Relation of carbon 14 concentrations to saline water contamination of coastal aquifers

Naturally occurring stable or radioactive isotopes may be used in some places to identify the origin of saline water that contaminates some coastal aquifers. In a recent study to determine the origin of saline water in the Ocala Limestone aquifer near Brunswick, Georgia, the following sources were analyzed for C 14 and deuterium concentrations: potable water from the Ocala Limestone, contaminated water from the Ocala Limestone, saune water from the underlying Claiborne Group, and nearby ocean water. The chloride concentration of the groundwater ranges from about 25 ppm in the potable water to more than 2000 ppm in the deeper part of the Claiborne Group. From an interpretation of piezometric maps and other hydrologic data, previous investigators had concluded that the source of the contaminating water was the Claiborne Group and not the nearby ocean. The essentially uniform range of low values of −965 to −987‰ of the modern standard (National Bureau Standard C 14 oxalic acid) for the C 14 activity of the groundwater samples (regardless of the degree of contamination) is in agreement with this conclusion. If recent ocean water, which had a C 14 value of +285‰, were the source of contamination, the contaminated water would have had a C 14 activity higher than the activity of the fresh water. Deuterium analyses are not inconsistent with the interpretation that water from the Claiborne Group, rather than recent ocean water, is the source of the contaminating water. The concurrence of the hydrologic and the isotopic data in this area where the hydrology is well known suggests that isotopic analysis may be used to identify the origin of water in different portions of a hydrologic environment.

Georgia↗
USGS1997

A time-depth scale for Owens Lake sediments of core OL-92; radiocarbon dates and constant mass-accumulation rate

Results of radiocarbon analyses of carbonates and humates from the upper 31 m of OL-92 indicate coherent and linear progression of dates with depth down to about 24 m and 30 ka. Scatter of results below this depth indicates that the practical limit of radiocarbon dating in this core is about 30 ka. The average mass-accumulation rate (MAR) for the top 24 m is 52.4 g/cm 2 /k.y. calculated from radiocarbon dates and bulk density reconstruction. A similar calculation for the entire core down to the Bishop ash bed (304 m, 759 ka) gives a MAR of 51.4 g/cm 2 /k.y., suggesting a constant MAR throughout the past 760 k.y. A time-depth curve for the entire core was then constructed from this constant value and using pore-water content to correct for sediment compaction. The resulting curve is remarkably coincident with a similar plot independently derived from 10 within-Brunhes paleomagnetic events identified by Glen et al. (this volume). That MAR remained relatively constant through the glacial/interglacial cycles may imply that the increased sediment supply during the high runoff of glacial times was balanced by increased size of the depositional area and vice-versa during interglacials. Surface area of the lake is approximately proportional to river discharge, but only up to the spill point of the lake. The constant MAR suggests, therefore, that spilling of Owens Lake was relatively infrequent during the past 800 k.y., as independently inferred from the sediment geochemistry (Bischoff et al., this volume, chapter 4).

California↗
USGS1996

Neogene and Quaternary geology of a stratigraphic test hole on Horn Island, Mississippi Sound

During April and May, 1991, the U.S. Geological Survey (USGS) drilled a 510-ft-deep, continuously cored, stratigraphic test hole on Horn Island, Mississippi Sound, as part of a field study of the Neogene and Quaternary geology of the Mississippi coastal area. The USGS drilled two new holes at the Horn Island site. The first hole was continuously cored to a depth of 510 ft; coring stopped at this depth due to mechanical problems. To facilitate geophysical logging, an unsampled second hole was drilled to a depth of 519 ft at the same location.

Open-File Report↗
USGS1991

Holocene Treeline Fluctuations in the Northern San Juan Mountains, Colorado, U.S.A., as Indicated by Radiocarbon-Dated Conifer Wood

An early to mid-Holocene warm period with greater than present-day monsoonal circulation is indicated by evidence in the northern San Juan Mountains of southwestern Colorado. Fifty radiocarbon ages of coniferous wood fragments, and several other radiocarbon ages of willow fragments, woody peat, and organic sediment associated with conifer remains, recovered from six sites at or above present-day treeline indicate that during the first half of the Holocene treeline was higher than present. Radiocarbon ages of coniferous wood fragments recovered from the remains of Lake Emma, a former glacial tarn above present-day treeline, indicate that between 9600 and 5400 BP treeline in the northern San Juan Mountains was at least 80 m higher than present. Furthermore, a radiocarbon age of a large spruce fragment with a complacent annual-ring record suggests that at about 8000 BP timberline may have been at least 140 m higher than present. These data suggest that during the early to mid-Holocene average July temperatures were at least 0.5 to 0.9°C higher than present. Radiocarbon ages and stratigraphy from bogs in the study area near present-day treeline suggest that between 5400 and 3500 BP treeline was near its present-day limits. After 3500 BP treeline was generally lower than present although short climatic ameliorations, with accompanying rises in treeline, may have occurred at about 3100 and 2400 BP. Deuterium concentrations previously determined for the cellulose of 18 conifer fragments from the Lake Emma site indicate a 70‰ decrease in deuterium from 9600 BP to present. These data indicate that the early Holocene increase in July solar radiation may have resulted in the intensification of the Arizona monsoon at that time.

Colorado↗
USGS1985

Geologic evidence for recurrent moderate to large earthquakes near Charleston, South Carolina

Multiple generations of earthquake-induced sand blows in Quaternary sediments and soils near Charleston, South Carolina, are evidence of recurrent moderate to large earthquakes in that area. The large 1886 earthquake, the only historic earthquake known to have produced sand blows at Charleston, probably caused the youngest observed blows. Older (late Quaternary) sand blows in the Charleston area indicate at least two prehistoric earthquakes with shaking severities comparable to the 1886 event.

South Carolina↗
USGS1984

Graphite sample preparation for AMS in a high pressure and temperature press

A high pressure-temperature press is used to make target material for accelerator mass spectrometry. Graphite was produced from typical **1**4C samples including oxalic acid and carbonates. Beam strength of **1**2C was generally adequate, but random radioactive contamination by **1**4C made age measurements impractical.

Nuclear Instruments and Methods in Physics Researc↗
USGS1984

Holocene eruptive activity of El Chichón Volcano, Chiapas, Mexico

Geologic and radiometric-age data indicate that El Chichón was frequently and violently active during the Holocene, including eruptive episodes about 600, 1250, and 1700 years ago and several undated, older eruptions. These episodes, involving explosive eruptions of sulfur-rich magma and associated dome-growth processes, were apparently separated by intervals of approximately 350 to 650 years. Some of El Chichón's eruptions may correlate with unusual atmospheric phenomena around A.D. 1300 and possibly A.D. 623.

Science↗
USGS1983

The environmental history and present condition of Saudi Arabia's northern sand seas

Saudi Arabia's northern sand seas are composed dominantly of stable dune systems, even though the modern climate is arid. The stable dunes are large and support a sparse semidesert vegetation. Active dunes are small and commonly confined to the crests of stable dunes; they comprise less than 5 percent of the dunes in the sand seas. Both the stability of the major dune systems and the small percentage of active dunes in the modern environment indicate a significant decrease in the average velocity and frequency of sand-moving winds since the time of stable-dune deposition. Comparison of modern wind directions with dune trends indicates that southwesterly winds responsible for dune formation in the southern and western An Nafud sand sea and in Nafud Urayq are no longer prevailing winds. Lake deposits are locally interbedded with deposits of eolian sand and in the lee of stable dunes. Radiocarbon dating of calcareous lake deposits defines at least two episodes of moisture-effective climate and minimal eolianactivity: between about 32,000 and 24,000 B.P., just before the onset of the last worldwide glacial stade of the Pleistocene, and during the Holocene between about 8,500 and 5,000 B.P. One lake deposit is more than 38,000 years old and may have been deposited during an earlier pluvial episode about 85,000 to 70,000 B.P. Pollen extracted from these lake deposits indicates that vegetation during late Pleistocene and Holocene pluvial episodes was similar to the present semidesert vegetation; however, the density of shrubs and grasses on the dunes was greater. The main dune systems overlie the 32,000 to 24,000-yearold lake deposits, whereas the Holocene lakebeds are found in modern interdunal environments, usually at the base of stable dunes. The main dune systems probably formed between 24,000 and 8,500 B.P., during the last episode of worldwide cold temperatures. Increased windiness at this time is also recorded in the world's oceans and in both polar ice caps. Eolian sand below the older lake deposits was deposited before 32,000 B.P., and circumstantial evidence indicates that the sand seas may have begun to form as early as late Miocene. In the An Nafud, remnants of a middle Tertiary(?) surface suggest that the original sediment source for the An Nafud may have been the weathered sandstones that underlie this surface. After lacustrine deposition ceased in middle Holocene time, eolian activity increased slightly. Deflation on windward dune slopes has produced deflation scoops, which look like inverted deltas. The modern active dunes are composed of sand deflated from the stable dunes.

Open-File Report↗
USGS1979

The Parsonsburg Sand in the central Delmarva Peninsula, Maryland and Delaware

The Parsonsburg Sand, a surface sand largely of Wisconsin age, caps terraces east of some of the major streams and mantles broad areas on the uplands of the central Delmarva Peninsula, Maryland and Delaware. The main body of the formation east and south of Salisbury, Md., ranges from 1.25 to 6.00 m (4-20 ft) in thickness and is a medium-grained moderately feldspathic sand containing a relatively mature heavy-mineral suite. The sand is either stratified or massive, and in some areas contains peaty sand and silt-clay, typically at or near the base of the formation. The organic matter ranges in radiocarbon age from about 30,000 to about 13,000 years B.P. and contains microfloral assemblages suggesting that at the time the sand was deposited the climate was cooler and drier that it is at present. The region may have been a pine-birch barrens in which were small ponds, spruce bogs, and abundant shrubs. The distribution of the sand at or near the position of high stands of the Sangamon sea suggests that the Parsonsburg Sand was derived from sandy shore and nearshore deposits of Sangamon age. Deposition was in part eolian and in part fluvial and lacustrine, probably in small streams and ponds between sand dunes.

Professional Paper↗
USGS1975

Widespread late glacial and postglacial tephra deposits from Mount St. Helens Volcano, Washington

Pumice layers composing four different groups of tephra beds (termed "sets"), whose stratigraphy, age, and trend away from Mount St. Helens are fairly well known, are potentially valuable stratigraphic markers in the northwestern United States and adjacent parts of Canada. All four tephra sets are less than about 18,000 yr old. The oldest set described (set S) is between about 18,000 and 12,000 yr old; the most extensive pumice layers of the set, however, probably are no more than about 13,000 yr old. Relatively voluminous layers in the next younger tephra unit (set J) probably range from slightly less than 12,000 to slightly more than 8,000 yr old; in the overlying set Y, the most extensive layers range from about 4,000 to 3,400 yr old. The largest tephra layers in the youngest tephra set described, set W, are apparently all about 450 yr old. All the extensive tephra deposits were carried chiefly east of Mount St. Helens, and the bulk of them form an arc which extends from north-northeast of the volcano clockwise around to the southeast.

Washington↗
USGS1975

Radiocarbon dates indicate rates of graben downfaulting, San Jacinto Valley, California

Recent radiocarbon dates for wood samples collected from three depths in San Jacinto Valley graben indicate active tectonic downfaulting during the past 42,000 yr. The flood plain of graded San Jacinto River, entering the valley from the southeast and leaving toward the west, serves as a reference datum across the graben. Depositional rates suggest that downfaulting averaged about 0.007 ft (2.1 mm)/yr from 42,000 to 15,270 yr B.P. and since 15,270 yr B.P. has increased to about 0.019 ft (5.8 mm)/yr.

California↗