Geology topics
Frank T. Manheim
Publications and source records attributed to Frank T. Manheim.
Size analysis, visual estimation of phosphate and other minerals, and preliminary estimation of recoverable phosphate in size fractions of sediment samples from drillholes GAT-90, Tybee Island, and GAS-90-2, Skidaway Island, Georgia
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Mineral resources of the U.S. Atlantic continental margin
Most geologic materials may be usable resources in some form and at some time, whether it be for general land fill and aggregate, beach replenishment, construction material, or as a source of metals and fuels. Thus, most natural materials occurring within the Atlantic continental margin are resources, defined as “materials, including those only surmised to exist, that have present or anticipated future value” (U.S.G.S., 1980). Whether a resource becomes a reserve or not (an economically recoverable commodity) depends upon the properties and economic values of that material, which are determined by the following factors: (a) availability, concentration, and occurrence of the material; (b) methods of recovering and processing the commodity; (c) transportation costs of ore and beneficiated products; and (d) environmental setting and costs of permitting and mitigation. Also, the economics of a given mineral resource change dramatically in response to new technological advances, discoveries of new deposits, or as industrial and social demands change through time. An increasingly critical component associated with the economics for development of any mineral commodity, is a good geologic knowledge of the resource base.
Options for radioactive and other hazardous waste siting within the U. S. Exclusive Economic Zone
Some areas of the E.E.Z. (Exclusive Economic Zone) offer technical, political and economic options that may complement existing approaches to hazardous waste storage and disposal.
Resource potential of the western North Atlantic Basin
We here consider the petroleum resources only of the off shelf portion of the western North Atlantic Ocean. Very little information is available for this region; off the eastern United States, only four petroleum exploration holes have been drilled in one restricted area seaward of the shelf, off the Baltimore Canyon trough. However, by interpreting seismic reflection profiles and Stratigraphie data from the Deep Sea Drilling Project (DSDP) and other wells on the adjacent slope and shelf, we can evaluate the geologic conditions that existed during development of the basin and that might lead to petroleum accumulations. The wellknown factors that lead to oil and gas accumulations are availability of source beds, adequate maturation, and the presence of reservoir beds and seals configured to create a trap. The western boundary of the area considered in this paper, the present sloperise break, is one that has developed from the interplay of sedimentation and erosion at the continental margin; these processes are affected by variations in margin subsidence, sedi-ment input, oceanic circulation, sea level, and other factors. Thus the sloperise break has migrated over time and is locally underlain by slope and shelf deposits, as well as deepbasin facies. These changes in depositional environments may well have caused juxtaposition of source and reservoir beds with effective seals.
Determination of interstitial chloride in shales and consolidated rocks by a precision leaching technique
We have devised a technique for determining chloride in interstitial water of consolidated rocks. Samples of rocks ranging from 5 to 10 g are crushed and sieved under controlled conditions and then ground with distilled water to submicron size in a closed mechanical mill. After ultra-centrifugation, chloride content is determined by coulometric titration. The chloride concentrations and total pore-water concentrations, obtained earlier from the same pore-water concentrations, obtained earlier from the same samples by low-temperature vacuum desiccation, are used to arrive at the "original" pore-water chloride concentrations by a simple iteration procedure. Interstitial chlorinity results obtained from Cretaceous and Jurassic strata in the Gulf of Mexico coastal areas ranged from 20 to 100 g/kg Cl with reproducibility approaching +/- 1%. We have also applied the technique to igneous and metamorphic bedrocks as well as ocean basalts containing 1 % water or less. Chloride values ranging from 6.7 to 20 g/kg with a reproducibility of about 5% were obtained.
Ferromanganese crusts from Necker Ridge, Horizon Guyot and S.P. Lee Guyot: Geological considerations
Necker Ridge, Horizon Guyot and S.P. Lee Guyot in the Central Pacific were sampled, seismically surveyed, and photographed by bottom cameras in order to better understand the distribution, origin, and evolution of ferromanganese crusts. Necker Ridge is over 600 km long with a rugged crest, pods of sediment to 146 m thick, slopes that average 12° to 20°, and debris aprons that cover some of the lower flanks. Substrate lithologies are mostly hyaloclastite, volcaniclastic breccia, and minor alkalic basalt. Horizon Guyot, 300 km long and 75 km wide, is capped by at least 160 m of sediment, which buries stepped terraces. Substrate lithologies are similar to those on Necker Ridge, although previous workers sampled much tholeiitic basalt on Horizon. S.P. Lee Guyot, 125 km long and 80 km wide, is capped by at least 300 m of sediment, and contains talus aprons along its lower flanks. Ferromanganese-encrusted rocks were recovered in every dredge and are thickest on Necker Ridge. Crust thicknesses average about 2.5, 1.5, and 0.8 cm for Necker, Horizon, and S.P. Lee, respectively. Crusts range from smooth or porous surfaces to knobby and botryoidal. The entire crust is laminated, however, two distinct layers commonly exist, separated by a paper-thin layer of phosphorite. The dominant mineral of all crusts is vernadite (δ-MnO 2 ), while quartz, feldspar, apatite, and, in three rocks todorokite, are minor phases. Quartz and feldspar decrease with decreasing latitude of occurrence, and is suggested to be related to eolian input. On the average, apatite also increases within the crusts with decreasing latitude of occurrence, which may be related to high biological productivity in the zone of equatorial upwelling. Phosphorite substrates are more abundant on Necker Ridge and S.P. Lee Guyot than they are on Horizon Guyot. Seamount ferromanganese nodules are distinct from abyssal nodules in their chemistry and internal structure.
Potential of cobalt and other metals in ferromanganese crusts on seamounts of the Central Pacific Basin
No abstract available.
An extensive data base for cobalt-rich ferromanganese crusts from the world oceans
A new database for ferromanganese crusts from the world oceans is being compiled by the U.S. Geological Survey. Crusts differ from abyssal nodules by forming principally on steeper, raised areas or current-swept plateaus in the oceans. Some crusts contain relatively large concentrations of cobalt (1.0%) in areas within national territorial jurisdictions.
Extraction and investigative techniques for study of interstitial waters of unconsolidated sediments: A review
No abstract available.
Manganese-phosphorite deposits of the Blake Plateau (Western North-Atlantic Ocean)
No abstract available.
Co-rich ferromanganese deposits in the marginal seamount regions of the Central Pacific Basin, results of the Midpac 1981
No abstract available.
Hydrochemistry of formation fluids in onshore and offshore strata in the Southeast Georgia Embayment
No abstract available.