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Geology topics

R. B. Moore

Publications and source records attributed to R. B. Moore.

At least 37 records · Page 2Linked to original sources
USGS1996

Late Wisconsinan deglaciation styles of parts of the Contoocook, Souhegan, and Piscataquog drainage basins, New Hampshire

This report is the guidebook for the 56th annual meeting and field conference of the Friends of the Pleistocene, held May 22 and 23, 1993. Features were examined at 11 sites in the Contoocook, Souhegan, and Piscataquog Drainage Basins to illustrate the geologic history of this area, about 14,000 years ago, during the time of deglaciation. The Contoocook River Basin is the largest river basin that drains north in New Hampshire and is similar to northwardly draining parts of the Piscataquog and Souhegan River basins. During the retreat of the ice, the drainage divide between adjacent drainage basins acted as a dam and lakes formed behind it. As the ice continued to melt farther north, drainage outlets were uncovered at progressively lower altitudes along the drainage divide. This resulted in catastrophic draining of the lakes. Evidence for the existence of the lakes includes fine-grained lake-bottom deposits and deltas at successively lower elevations. Geomorphic evidence for the catastrophic draining includes Pulpit Rock in Bedford, N.H. and V-shaped notches eroded into till and bedrock. In Henniker, N.H., further evidence of catastrophic draining of a large lake in the Contoocook River Basin is a combination alluvial fan and delta that formed when rapidly draining lake water flowed across a till slope, eroded the till, and redeposited the material where it entered a smaller, much lower lake.

Open-File Report↗
USGS1995

Ground-water resources in New Hampshire: Stratified-drift aquifers

Stratified-drift aquifers underlie about 14 percent of the land surface in New Hampshire and are an important source of ground water for commercial, industrial, domestic, and public-water supplies in the State. This report introduces terms and concepts relevant to ground-water resources, summarizes some of the important information derived from a statewide stratified-drift-aquifer investigation, and provides examples of how the findings are used. The purpose of this report is to provide an overview of the stratified-drift aquifer assessment program, thus making summary information accessible to a broad audience, including legislators, State and local officials, and the public. Different audiences will use the report in different ways. To accommodate the varied audiences, some data are summarized statewide, some are presented by major river basin, and some are provided by town. During data collection, care was taken to use consistent methods for each of the 13 study areas (fig. 1) so that results would be comparable throughout the State . If more specific or detailed information about a particular area of interest is needed, the reader is directed to one or more of the technical reports listed in the Selected References section of this report.

New Hampshire↗
USGS1994

Petrology of gabbroic xenoliths in 1960 Kilauea basalt: crystalline remnants of prior (1955) magmatism

The 1960 Kapoho lavas of Kilauea's east rift zone contain 1-10 cm xenoliths of olivine gabbro, olivine gabbro-norite, and gabbro norite. Textures are poikilitic (ol+sp+cpx in pl) and intergranular (cpx+pl??ol??opx). Poikilitic xenoliths, which we interpret as cumulates, have the most primitive mineral compositions, Fo82.5, cpx Mg# 86.5, and An80.5. Many granular xenoliths (ol and noritic gabbro) contain abundant vesicular glass that gives them intersertal, hyaloophitic, and overall 'open' textures to suggest that they represent 'mush' and 'crust' of a magma crystallization environment. Their phase compositions are more evolved (Fo80-70, cpx Mg# 82-75, and An73-63) than those of the poikilitic xenoliths. Associated glass is basaltic, but evolved (MgO 5 wt%; TiO2 3.7-5.8 wt%). The gabbroic xenolith mineral compositions fit existing fractional crystallization models that relate the origins of various Kilauea lavas to one another. FeO/MgO crystal-liquid partitioning is consistent with the poikilitic ol-gabbro assemblage forming as a crystallization product from Kilauea summit magma with ???8 wt% MgO that was parental to evolved lavas on the east rift zone. For example, least squares calculations link summit magmas to early 1955 rift-zone lavas (???5 wt% MgO) through ???28-34% crystallization of the ol+sp+cpx+pl that comprise the poikilitic ol-gabbros. The other ol-gabbro assemblages and the olivine gabbro-norite assemblages crystallized from evolved liquids, such as represented by the early 1955 and late 1955 lavas (???6.5 wt% MgO) of the east rift zone. The eruption of 1960 Kapoho magmas, then, scoured the rift-zone reservoir system to entrain portions of cumulate and solidification zones that had coated reservoir margins during crystallization of prior east rift-zone magmas. ?? 1994 Springer-Verlag.

Bulletin of Volcanology↗
USGS1994

Geohydrology and water quality of stratified-drift aquifers in the lower Connecticut River basin, southwestern New Hampshire

Stratified-drift aquifers discontinuously underlie 116 square miles of the Lower Connecticut River basin in southwestern New Hampshire, which has a total drainage area of 1,163 square miles. Saturated thicknesses of stratified drift within the study area are locally greater than 400 feet but generally are less. Transmissivities 1ocally exceeds 4,000 feet squared per day but are generally much less. The 20.8 square mile, or 1.8 percent, of the study area identified as having transmissivity greater than 1,000 feet squared per day represents a valuable resource. The geohydrology of stratified- drift aquifers was investigated by focusing on basic aquifer properties, including aquifer boundaries; recharge, discharge, and direction of ground-water flow; saturated thickness and storage; and transmissivity. Surficial geologic mapping assisted in the determination of aquifer boundaries. Data from more than 2,300 wells, test borings, and springs were used to produce maps of water-table altitude, saturated thickness, and transmissivity of-stratified drift. Seismic-refraction profiles were completed at 29 locations in the study area. These profiles aided in the construction of the water-table and saturated-thickness maps. Seismic- reflection data were also collected along 60 miles of the Connecticut River. A stratified-drift aquifer in southern Croydon and northern Newport was analyzed for aquifer yield using transient simulations and a two-dimensional, finite-difference ground-water-flow model. The objective was to estimate the yield after a 180-day period of pumping. Two hypothetical wells were pumped at 1.0 Mgal/d and 0.5 Mgal/d for 180 days respectively. The amount of water available for infiltration was the limiting factor. Results of analysis of water samples from 22 wells and 8 spring show that, with some exceptions, water in the stratified-drift aquifer generally meets the U.S. Environmental Protection Agency's primary and secondary drinking-water regulations.

Water-Resources Investigations Report↗
USGS1993

The hydrothermal-convection systems of kilauea: an historical perspective

Kilauea is one of only two basaltic volcanoes in the world where geothermal power has been produced commercially. Little is known about the origin, size and longevity of its hydrothermal-convection systems. We review the history of scientific studies aimed at understanding these systems and describe their commercial development. Geothermal energy is a controversial issue in Hawai'i, partly because of hydrogen sulfide emissions and concerns about protection of rain forests. ?? 1993.

Geothermics↗
USGS1993

Geology of kilauea volcano

This paper summarizes studies of the structure, stratigraphy, petrology, drill holes, eruption frequency, and volcanic and seismic hazards of Kilauea volcano. All the volcano is discussed, but the focus is on its lower cast rift zone (LERZ) because active exploration for geothermal energy is concentrated in that area. Kilauea probably has several separate hydrothermal-convection systems that develop in response to the dynamic behavior of the volcano and the influx of abundant meteoric water. Important features of some of these hydrothermal-convection systems are known through studies of surface geology and drill holes. Observations of eruptions during the past two centuries, detailed geologic mapping, radiocarbon dating, and paleomagnetic secular-variation studies indicate that Kilauea has erupted frequently from its summit and two radial rift zones during Quaternary time. Petrologic studies have established that Kilauea erupts only tholeiitic basalt. Extensive ash deposits at Kilauea's summit and on its LERZ record locally violent, but temporary, disruptions of local hydrothermal-convection systems during the interaction of water or steam with magma. Recent drill holes on the LERZ provide data on the temperatures of the hydrothermal-convection systems, intensity of dike intrusion, porosity and permeability, and an increasing amount of hydrothermal alteration with depth. The prehistoric and historic record of volcanic and seismic activity indicates that magma will continue to be supplied to deep and shallow reservoirs beneath Kilauea's summit and rift zones and that the volcano will be affected by eruptions and earthquakes for many thousands of years. ?? 1993.

Geothermics↗
USGS1993

Dynamic behavior of Kilauea Volcano and its relation to hydrothermal systems and geothermal energy

Exploitation of hydrothermal systems on active basaltic volcanoes poses some unique questions about the role of volcanism and hydrothermal system evolution. Volcanic activity creates and maintains hydrothermal systems while earthquakes create permeable fractures that, at least temporarily, enhance circulation. Magma and water, possibly hydrothermal water, can interact violently to produce explosive eruptions. Finally, we speculate on whether volcanic behavior can be affected by high rates of heat extraction.

Conference Paper↗
USGS1992

Volcanic geology and eruption frequency, lower east rift zone of Kilauea volcano, Hawaii

Detailed geologic mapping and radiocarbon dating of tholeiitic basalts covering about 275 km2 on the lower east rift zone (LERZ) and adjoining flanks of Kilauea volcano, Hawaii, show that at least 112 separate eruptions have occurred during the past 2360 years. Eruptive products include spatter ramparts and cones, a shield, two extensive lithic-rich tuff deposits, aa and pahoehoe flows, and three littoral cones. Areal coverage, number of eruptions and average dormant interval estimates in years for the five age groups assigned are: (I) historic, i.e. A D 1790 and younger: 25%, 5, 42.75; (II) 200-400 years old: 50%, 15, 14.3: (III) 400-750 years old: 20%, 54, 6.6; (IV) 750-1500 years old: 5%, 37, 20.8; (V) 1500-3000 years old: <1%, 1, unknown. At least 4.5-6 km3 of tholeiitic basalt have been erupted from the LERZ during the past 1500 years. Estimated volumes of the exposed products of individual eruptions range from a few tens of cubic meters for older units in small kipukas to as much as 0.4 km3 for the heiheiahulu shield. The average dormant interval has been about 13.6 years during the past 1500 years. The most recent eruption occurred in 1961, and the area may be overdue for its next eruption. However, eruptive activity will not resume on the LERZ until either the dike feeding the current eruption on the middle east rift zone extends farther down rift, or a new dike, unrelated to the current eruption, extends into the LERZ. ?? 1992 Springer-Verlag.

Bulletin of Volcanology↗