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Geology topics

R.J. Rosenbauer

Publications and source records attributed to R.J. Rosenbauer.

At least 19 recordsLinked to original sources
USGS2010

Application of organic geochemistry to coastal tar residues from central California

Tar residues are common on the coastline of the Monterey Bay National Marine Sanctuary. These coastal tar residues have been washed ashore and usually occur on headlands near the high-tide line. In this study, 18 coastal tar residues were collected and analyzed to determine their carbon isotopic compositions and the values of selected biomarker ratios. All of the residues have very heavy ( 13 C-enriched) carbon isotopic compositions spanning a narrow range (δ 13 C = −22.2 to −23.4‰), and 28,30-bisnorhopane is present in all samples. These same geochemical characteristics are found in Monterey Formation oils from which the coastal tar residues were likely derived. These coastal residues could result from natural seeps or from accidental spills. Statistically the coastal tar residues can be organized into three groups, each of which may represent different spill or seep events. Seven samples of potential local representative sources for the tar residues were examined, but none could account for the coastal tars.

California↗
USGS2009

A carbon, nitrogen, and sulfur elemental and isotopic study in dated sediment cores from the Louisiana Shelf

Three sediment cores were collected off the Mississippi River delta on the Louisiana Shelf at sites that are variably influenced by recurring, summer-time water-column hypoxia and fluvial loadings. The cores, with established chronology, were analyzed for their respective carbon, nitrogen, and sulfur elemental and isotopic composition to examine variable organic matter inputs, and to assess the sediment record for possible evidence of hypoxic events. Sediment from site MRJ03-3, which is located close to the Mississippi Canyon and generally not influenced by summer-time hypoxia, is typical of marine sediment in that it contains mostly marine algae and fine-grained material from the erosion of terrestrial C4 plants. Sediment from site MRJ03-2, located closer to the mouth of the Mississippi River and at the periphery of the hypoxic zone (annual recurrence of summer-time hypoxia >50%), is similar in composition to core MRJ03-3, but exhibits more isotopic and elemental variability down-core, suggesting that this site is more directly influenced by river discharge. Site MRJ03-5 is located in an area of recurring hypoxia (annual recurrence >75%), and is isotopically and elementally distinct from the other two cores. The carbon and nitrogen isotopic composition of this core prior to 1960 is similar to average particulate organic matter from the lower Mississippi River, and approaches the composition of C3 plants. This site likely receives a greater input of local terrestrial organic matter to the sediment. After 1960 and to the present, a gradual shift to higher values of δ 13 C and δ 15 N and lower C:N ratios suggests that algal input to these shelf sediments increased as a result of increased productivity and hypoxia. The values of C:S and δ 34 S reflect site-specific processes that may be influenced by the higher likelihood of recurring seasonal hypoxia. In particular, the temporal variations in the C:S and δ 34 S down-core are likely caused by changes in the rate of sulfate reduction, and hence the degree of hypoxia in the overlying water column. Based principally on the down-core C:N and C:S ratios and δ 13 C and δ 34 S profiles, sites MRJ03-3 and MRJ03-2 generally reflect more marine organic matter inputs, while site MRJ03-5 appears to be more influenced by terrestrial deposition.

Geo-Marine Letters↗
USGS2009

Peptide synthesis in early earth hydrothermal systems

We report here results from experiments and thermodynamic calculations that demonstrate a rapid, temperature-enhanced synthesis of oligopeptides from the condensation of aqueous glycine. Experiments were conducted in custom-made hydrothermal reactors, and organic compounds were characterized with ultraviolet-visible procedures. A comparison of peptide yields at 260??C with those obtained at more moderate temperatures (160??C) gives evidence of a significant (13 kJ ?? mol -1 ) exergonic shift. In contrast to previous hydrothermal studies, we demonstrate that peptide synthesis is favored in hydrothermal fluids and that rates of peptide hydrolysis are controlled by the stability of the parent amino acid, with a critical dependence on reactor surface composition. From our study, we predict that rapid recycling of product peptides from cool into near-supercritical fluids in mid-ocean ridge hydrothermal systems will enhance peptide chain elongation. It is anticipated that the abundant hydrothermal systems on early Earth could have provided a substantial source of biomolecules required for the origin of life. Astrobiology 9, 141-146. ?? 2009 Mary Ann Liebert, Inc. 2009.

Astrobiology↗
USGS2008

Experimental measurements of vapor-liquid equilibria of the H2O + CO2 + CH4 ternary system

Reported are the experimental measurements on vapor-liquid equilibria in the H2O + CO2 + CH4 ternary system at temperatures from (324 to 375) K and pressures from (10 to 50) MPa. The results indicate that the CH4 solubility in the ternary mixture is about 10 % to 40 % more than that calculated by interpolation from the Henry's law constants of the binary system, H2O + CH4, and the solubility of CO2 is 6 % to 20 % more than what is calculated by the interpolation from the Henry's law constants of the binary mixture, H 2O + CO2. ?? 2008 American Chemical Society.

Journal of Chemical and Engineering Data↗
USGS2008

An hydrothermal experimental study of the cobalt-cobalt oxide redox buffer

Equilibrium aqueous hydrogen concentration and corresponding energies of reaction, ??Grxno(T, P), for the reaction Co(s) + H2O(l) = CoO(s) + H2(aq) have been determined at temperatures between 256 and 355 ??C and at 400 bar. Steady-state concentrations of hydrogen were approached in experiments under conditions of both H2 excess and deficiency containing the solids Co, CoO and liquid water. All experiments were carried out in flexible gold and titanium reactors with the capability of on-line fluid sampling. Measured equilibrium molal concentrations of H2(aq) at 256, 274, 300, 324 and 355 ??C are 0.81(?? 0.01) ?? 10- 3 1.11(?? 0.01) ?? 10- 3, 1.92(?? 0.01) ?? 10- 3, 3.71(?? 0.06) ?? 10- 3, 7.54(?? 0.12) ?? 10- 3, respectively, and corresponding values of ??Grxno(T, P) in units kJ ?? mol- 1 are 31.4(?? 0.1), 31.0(?? 0.1), 29.8(?? 0.1), 27.7(?? 0.5) and 25.5(?? 0.9), respectively. Using published heat capacity data for Co(s) and CoO(s) and - 79.6 J ?? mol- 1 ?? K- 1 for the entropy of formation of CoO we calculated for this study a value for ??GCoO,Tr,Pro = - 214.5(?? 0.9) kJ ?? mol- 1 and ??HCoO,Tr,Pro = - 238.3(?? 0.9) kJ ?? mol- 1 at 25 ??C and 1 bar. The value of ??HCoO,Tr,Pro determined in this study compares well with the reported calorimetric value of - 238.9(?? 1.2) kJ ?? mol- 1 [Boyle, B.J., King, E.G., Conway, K.C., 1954. Heats of formation of nickel and cobalt oxides (NiO and CoO) by combustion calorimetry. Journal of the American Chemical Society, 76, 3835-3837]. ?? 2008 Elsevier B.V. All rights reserved.

Chemical Geology↗
USGS2008

Families of miocene monterey crude oil, seep, and tarball samples, coastal California

Biomarker and stable carbon isotope ratios were used to infer the age, lithology, organic matter input, and depositional environment of the source rocks for 388 samples of produced crude oil, seep oil, and tarballs to better assess their origins and distributions in coastal California. These samples were used to construct a chemometric (multivariate statistical) decision tree to classify 288 additional samples. The results identify three tribes of 13C-rich oil samples inferred to originate from thermally mature equivalents of the clayey-siliceous, carbonaceous marl and lower calcareous-siliceous members of the Monterey Formation at Naples Beach near Santa Barbara. An attempt to correlate these families to rock extracts from these members in the nearby COST (continental offshore stratigraphic test) (OCS-Cal 78-164) well failed, at least in part because the rocks are thermally immature. Geochemical similarities among the oil tribes and their widespread distribution support the prograding margin model or the banktop-slope-basin model instead of the ridge-and-basin model for the deposition of the Monterey Formation. Tribe 1 contains four oil families having geochemical traits of clay-rich marine shale source rock deposited under suboxic conditions with substantial higher plant input. Tribe 2 contains four oil families with traits intermediate between tribes 1 and 3, except for abundant 28,30-bisnorhopane, indicating suboxic to anoxic marine marl source rock with hemipelagic input. Tribe 3 contains five oil families with traits of distal marine carbonate source rock deposited under anoxic conditions with pelagic but little or no higher plant input. Tribes 1 and 2 occur mainly south of Point Conception in paleogeographic settings where deep burial of the Monterey source rock favored petroleum generation from all three members or their equivalents. In this area, oil from the clayey-siliceous and carbonaceous marl members (tribes 1 and 2) may overwhelm that from the lower calcareous-siliceous member (tribe 3) because the latter is thinner and less oil-prone than the overlying members. Tribe 3 occurs mainly north of Point Conception where shallow burial caused preferential generation from the underlying lower calcareous-siliceous member or another unit with similar characteristics. In a test of the decision tree, 10 tarball samples collected from beaches in Monterey and San Mateo counties in early 2007 were found to originate from natural seeps representing different organofacies of Monterey Formation source rock instead from one anthropogenic pollution event. The seeps apparently became more active because of increased storm activity. Copyright ?? 2008. The American Association of Petroleum Geologists. All rights reserved.

American Association of Petroleum Geologists Bulle↗
USGS2006

Historical trace element distribution in sediments from the Mississippi River delta

Five sediment cores were collected on the shelf of the inner Mississippi Bight in June 2003 for a suite of radionuclides to establish geochronologies and trace elements to examine patterns of contaminant deposition and accumulation. Core sites were chosen to reflect a matrix of variable water depths, proximity to the Mississippi River mouth as the primary source for terrigenous particles, and extent and duration of summertime water column hypoxia. The vertical distribution of 239,240Pu and 210Pbxs (= 210Pbtotal - 226Ra) provided reliable geochronological age constraints to develop models for mass accumulation rates and historic trace element inputs and variations. Mass accumulation rates ranged from 0.27 to 0.87 g cm-2 yr-1 and were internally consistent using either 210Pbxs or 239,240Pu. Measured inventories of 137Cs, 239,240Pu, and 210Pbxs were compared to atmospheric deposition rates to quantify potential sediment focusing or winnowing. Observed variability in calculated mass accumulation rates may be attributed foremost to site-specific proximity to the river mouth (i.e., sediment source), variability in water depth, and enhanced sediment focusing at the Mississippi River canyon site. Trace element concentrations were first normalized to Al, and then Al-normalized enrichment factors (ANEF) were calculated based on preanthropogenic and crustal trace element abundances. These ANEFs were typically > 1 for V and Ba, while for most other elements studied, either no enrichment or depletion was observed. The enrichment of Ba may be related, in part, to the seasonal occurrence of oxygen-depleted subsurface waters off the Mississippi River delta, as well as being an ubiquitous by-product of the petroleum industry. ?? 2006 Estuarine Research Federation.

Estuaries and Coasts↗
USGS2005

Ferric iron in sediments as a novel CO2 mineral trap: CO 2-SO2 reaction with hematite

Thermodynamic simulations of reactions among SO2-bearing CO 2-dominated gas, water and mineral phases predict that Fe III in sediments should be converted almost entirely to dissolved FeII and siderite (FeCO3), and that SO2 should simultaneously be oxidized to dissolved sulfate. The reactions are however, subject to kinetic constraints which may result in deviation from equilibrium and the precipitation of other metastable mineral phases. To test the prediction, a laboratory experiment was carried out in a well stirred hydrothermal reactor at 150??C and 300 bar with hematite, 1.0 m NaCl, 0.5 m NaOH, SO2 in quantity sufficient to reduce much of the iron, and excess CO2. The experiment produced stable siderite and metastable pyrite and elemental S. Changes in total dissolved Fe are consistent with nucleation of pyrite at ???17 h, and nucleation of siderite at ???600 h. Dissolution features present on elemental S at the conclusion of the experiment suggest nucleation early in the experiment. The experiment did not reach equilibrium after ???1400 h, as indicated by coexistence of hematite with metastable pyrite and elemental sulfur. However, the results confirm that FeIII can be used to trap CO2 in siderite if partly oxidized S, as SO2, is present to reduce the Fe with CO2 in the gas phase. ?? 2005 Elsevier Ltd. All rights reserved.

Applied Geochemistry↗
USGS2005

Experimental investigation of CO2-brine-rock interactions at elevated temperature and pressure: Implications for CO2 sequestration in deep-saline aquifers

Deep-saline aquifers are potential repositories for excess CO 2 , currently being emitted to the atmosphere from anthropogenic activities, but the reactivity of supercritical CO 2 with host aquifer fluids and formation minerals needs to be understood. Experiments reacting supercritical CO 2 with natural and synthetic brines in the presence and absence of limestone and plagioclase-rich arkosic sandstone showed that the reaction of CO 2 -saturated brine with limestone results in compositional, mineralogical, and porosity changes in the aquifer fluid and rock that are dependent on initial brine composition, especially dissolved calcium and sulfate. Experiments reacting CO 2 -saturated, low-sulfate brine with limestone dissolved 10% of the original calcite and increased rock porosity by 2.6%. Experiments reacting high-sulfate brine with limestone, both in the presence and absence of supercritical CO 2 , were characterized by the precipitation of anhydrite, dolomitization of the limestone, and a final decrease in porosity of 4.5%. However, based on favorable initial porosity changes of about 15% due to the dissolution of calcite, the combination of CO 2 co-injection with other mitigation strategies might help alleviate some of the well-bore scale and formation-plugging problems near the injection zone of a brine disposal well in Paradox Valley, Colorado, as well as provide a repository for CO 2 . Experiments showed that the solubility of CO 2 is enhanced in brine in the presence of limestone by 9% at 25 °C and 6% at 120 °C and 200 bar relative to the brine itself. The solubility of CO 2 is enhanced also in brine in the presence of arkosic sandstone by 5% at 120 °C and 300 bar. The storage of CO 2 in limestone aquifers is limited to only ionic and hydraulic trapping. However, brine reacted with supercritical CO 2 and arkose yielded fixation and sequestration of CO 2 in carbonate mineral phases. Brine desiccation was observed in all experiments containing a discrete CO 2 phase, promoting porosity-reducing precipitation reactions in aquifers near saturation with mineral phases.

Colorado↗
USGS2004

Geochemical characterization of tarballs on beaches along the California coast. Part I - Shallow seepage impacting the Santa Barbara Channel Islands, Santa Cruz, Santa Rosa and San Miguel

Tarballs are common along the southern California coastline. This study investigates tarballs from beaches along this coastline, with a focus on Santa Cruz, Santa Rosa, and San Miquel Islands in the Santa Barbara Channel. The tarballs were fingerprinted using biomarker and stable carbon isotope parameters, and then grouped according to genetic similarities. The data show that the tarballs are of natural and not anthropogenic origin and that all originate from source rock within the Miocene Monterey Formation via shallow seeps offshore. Sterane biomarker parameters were found to vary widely in the sample set. Biodegradation, especially of the regular steranes, is the primary process impacting the biomarker distributions in a large group of samples. The most common tarball occurrences appear to come from offshore seepage near the west end of Santa Cruz Island. Another major group most likely was transported north from near Santa Monica Bay. Several individual occurrences of some of these tarball groups also were found on beaches as far north as Pt. Reyes and as far south as San Diego, indicating significant long-distance dispersal by ocean currents. This study begins a library of tarball fingerprints to be used as a database to help distinguish between natural and anthropogenic tar occurrences all along the California coast, and to compare shallow seepage with future samples of deeper production oils from the same area.

Organic Geochemistry↗
USGS2003

Induction of lupus autoantibodies by adjuvants

Exposure to the hydrocarbon oil pristane induces lupus specific autoantibodies in non-autoimmune mice. We investigated whether the capacity to induce lupus-like autoimmunity is a unique property of pristane or is shared by other adjuvant oils. Seven groups of 3-month-old female BALB/cJ mice received a single intraperitoneal injection of pristane, squalene (used in the adjuvant MF59), incomplete Freund's adjuvant (IFA), three different medicinal mineral oils, or saline, respectively. Serum autoantibodies and peritoneal cytokine production were measured. In addition to pristane, the mineral oil Bayol F (IFA) and the endogenous hydrocarbon squalene both induced anti-nRNP/Sm and -Su autoantibodies (20% and 25% of mice, respectively). All of these hydrocarbons had prolonged effects on cytokine production by peritoneal APCs. However, high levels of IL-6, IL-12, and TNF?? production 2-3 months after intraperitoneal injection appeared to be associated with the ability to induce lupus autoantibodies. The ability to induce lupus autoantibodies is shared by several hydrocarbons and is not unique to pristane. It correlates with stimulation of the production of IL-12 and other cytokines, suggesting a relationship with a hydrocarbon's adjuvanticity. The potential to induce autoimmunity may complicate the use of oil adjuvants in human and veterinary vaccines. ?? 2003 Elsevier Ltd. All rights reserved.

Journal of Autoimmunity↗
USGS2002

Vapor-liquid phase equilibria of potassium chloride-water mixtures: Equation-of-state representation for KCl-H2O and NaCl-H2O

Measurements of isothermal vapor-liquid compositions for KCl-H2O as a function of pressure are reported. An equation of state, which was originally proposed by Pitzer and was improved and used by Tanger and Pitzer to fit the vapor-liquid coexistence surface for NaCl-H2O, has been used for representation of the KCl-H2O system from 300 to 410??C. Improved parameters are also reported for NaCl-H2O from 300 to 500??C. ?? 1990 American Chemical Society.

Journal of Physical Chemistry↗
USGS2002

Hydrocarbon geochemistry of cold seeps in the Monterey Bay National Marine Sanctuary

Samples from four geographically and tectonically discrete cold seeps named Clam Flat, Clamfield, Horseshoe Scarp South, and Tubeworm City, within the Monterey Bay National Marine Sanctuary were analyzed for their hydrocarbon content. The sediment contains gaseous hydrocarbons and CO2, as well as high molecular weight aliphatic and aromatic hydrocarbons with various combinations of thermogenic and biogenic contributions from petroleum, marine, and terrigenous sources. Of particular interest is the cold seep site at Clamfield which is characterized by the presence of thermogenic hydrocarbons including oil that can likely be correlated with oil-saturated strata at Majors Creek near Davenport, CA, USA. At Clam Flat, the evidence for thermogenic hydrocarbons is equivocal. At Horseshoe Scarp South and Tubeworm City, hydrocarbon gases, mainly methane, are likely microbial in origin. These varied sources of hydrocarbon gases highlight the diverse chemical systems that appear at cold seep communities. ?? 2002 Elsevier Science B.V. All rights reserved.

Marine Geology↗
USGS1999

PAH refractory index as a source discriminant of hydrocarbon input from crude oil and coal in Prince William Sound, Alaska

Geochemical correlation and differentiation of hydrocarbons from crude oils and coals is difficult. The complex mixture of the hydrocarbon constituents and the dynamic nature of these constituents in the environment as they weather contribute to this difficulty A new parameter, the polycyclic aromatic hydrocarbon (PAH) refractory index, is defined here to help in this correlation. The PAH refractory index is a ratio of two of the most refractory constituents of most crude oils, namely triaromatic steranes and monomethylchrysenes. These are among the most persistent compounds in oil after deposition in the environment and thus retain reliably the signature of the original petroleum input. This index is utilized in Prince William Sound (PWS) to differentiate three different oils, as well as to provide evidence that coal, not oil, is the dominant source of the PAHs which are prominent constituents of marine sediments from PWS and the Gulf of Alaska.Geochemical correlation and differentiation of hydrocarbons from crude oils and coals is difficult. The complex mixture of the hydrocarbon constituents and the dynamic nature of these constituents in the environment as they weather contribute to this difficulty. A new parameter, the polycyclic aromatic hydrocarbon (PAH) refractory index, is defined here to help in this correlation. The PAH refractory index is a ratio of two of the most refractory constituents of most crude oils, namely triaromatic steranes and monomethylchrysenes. These are among the most persistent compounds in oil after deposition in the environment and thus retain reliably the signature of the original petroleum input. This index is utilized in Prince William Sound (PWS) to differentiate three different oils, as well as to provide evidence that coal, not oil, is the dominant source of the PAHs which are prominent constituents of marine sediments from PWS and the Gulf of Alaska.

Conference Paper↗
USGS1998

Natural hydrocarbon background in benthic sediments of Prince William Sound, Alaska: Oil vs coal

The source of the background hydrocarbons in benthic sediments of Prince William Sound (PWS), AK, where the 1989 Exxon Valdez oil spill (EVOS) occurred, has been ascribed to oil seeps in coastal areas of the Gulf of Alaska (GOA). We present evidence that coal is a more plausible source, including (i) high concentrations of total PAH (TPAH), between 1670 and 3070 ng/g, in continental shelf sediments adjacent to the coastal region containing extensive coal deposits; (ii) PAH composition patterns of sediments along with predictive models that are consistent with coal but not oil; (iii) low ratios (<0.2) of triaromatic steranes to methylchrysenes found in sediments and coals, contrasting with the high ratios (11 and 13) found in seep oil; and (iv) bioaccumulation of PAH in salmon collected within 100 m of the Katalla oil seeps but not in filter-feeding mussels collected near oilfield drainages 9 km from the seeps, indicating negligible transport of bioavailable PAH from Katalla seeps to the GOA. In contrast with oil, PAH in coal are not bioavailable, so the presence of coal in these benthic sediments confers no adaptive benefit to biota of the marine ecosystem with respect to PAH insults from anthropogenic sources.The source of the background hydrocarbons in benthic sediments of Prince William Sound (PWS), AK, where the 1989 Exxon Valdez oil spill (EVOS) occurred, has been ascribed to oil seeps in coastal areas of the Gulf of Alaska (GOA). We present evidence that coal is a more plausible source, including (i) high concentrations of total PAH (TPAH), between 1670 and 3070 ng/g, in continental shelf sediments adjacent to the coastal region containing extensive coal deposits; (ii) PAH composition patterns of sediments along with predictive models that are consistent with coal but not oil; (iii) low ratios (<0.2) of triaromatic steranes to methylchrysenes found in sediments and coals, contrasting with the high ratios (11 and 13) found in seep oil; and (iv) bioaccumulation of PAH in salmon collected within 100 m of the Katalla oil seeps but not in filter-feeding mussels collected near oilfield drainages 9 km from the seeps, indicating negligible transport of bioavailable PAH from Katalla seeps to the GOA. In contrast with oil, PAH in coal are not bioavailable, so the presence of coal in these benthic sediments confers no adaptive benefit to biota of the marine ecosystem with respect to PAH insults from anthropogenic sources.

Environmental Science & Technology↗
USGS1994

Karstification without carbonic acid: Bedrock dissolution by gypsum- driven dedolomitization

Aggressive karstification can take place where dolomite and gypsum are in contact with the same aquifer. Gypsum dissolution drives the precipitation of calcite, thus consuming carbonate ions released by dolomite. Lake Banyoles, in northeastern Spain, is a karst lake supplied by sublacustrine springs, and karstic collapse is occurring in the immediate vicinity of the lake. Lake water is dominated by Mg-Ca and SO 4 -HCO 3 , and is supersaturated with calcite that is actively accumulating in lake sediments. Water chemistry, sulfur isotope composition, local stratigraphy, and mass-balance modelling suggest that the primary karst-forming process at at Lake Banyoles is dedolomitization of basement rocks driven by gypsum dissolution. Karstification takes place along the subsurface contact between the gypsiferous Beuda Formation and the dolomitic Perafita Formation. This process is here recognized for the first time to cause karstification on a large scale; this is significant because it proceeds without the addition of soil-generated carbonic acid. Gypsum-driven dedolomitization may be responsible for other karstic systems heretofore attributed to soil-generated carbonic acid.

Geology↗