Speculations on the petroleum geology of the accretionary body: an example from the central Aleutians     

Jill McCarthy  Andrew J. Stevenson  David W. Scholl  Tracy L. Vallier 《Marine and Petroleum Geology》1984,1(2):151-167

In the 300 km wide Adak-Amlia sector of the central Aleutian Trench ≈ 36 000 km³ of offscraped trench fill makes up the wedge-shaped mass of the Aleutian accretionary body. Within this wedge, seismic reflection profiles reveal an abundance of potential hydrocarbon-trapping structures. These structures include antiforms, thrust and normal faults, and stratigraphic pinchouts. Maximum closure on these features is 2 km. In addition, the silt and possibly sand size sediment within the offscraped turbidite deposits, and the porous diatomaceous pelagic deposits interbedded with and at the base of the wedge, may define suitable reservoirs for the entrapment of hydrocarbons. Potential seals for these reservoirs include diagenetically-altered and -produced siliceous and carbonate sediment. The organic carbon input into the central Aleutian Trench, based on carbon analyses of DSDP Legs 18 and 19 core samples, suggests that the average organic carbon content within the accretionary body is approximately 0.3–0.6%. Heat flow across the Aleutian Terrace indicates that at present the oil generation window lies at a depth of 3–6.5 km. At depths of 8 km (which corresponds to the maximum depth the offscraped sediment has been seismically resolved beneath the lower trench slope), the probable high (170–180°C) temperatures prohibit all but gas generation. The dewatering of trench sediment and subducted oceanic crust should produce an abundance of fluids circulating within the accretionary body. These fluids and gases can conduct hydrocarbons to any of the abundant trapping geometries or be lost from the system through sea floor seepage. In the Aleutian accretionary body all the conditions necessary for the formation of oil and gas deposits exist. The size and ultimate preservation of these deposits, however, are dependent on the deformational history of the prism both during accretion and after the accretion process has been superceded by subsequent tectonic regimes.  相似文献   

HAPPY CANYON: A NEW TYPE OF ENSTATITE ACHONDRITE     

Edward J. Olsen  T.E. Bunch  Eugene Jarosewich  Albert F. Noonan  Glenn I Huss 《Meteoritics & planetary science》1977,12(2):109-124

Happy Canyon [found: 1971, 34° 46.5′N, 101° 33.6′W, Texas] consists of about 85 vol. % enstatite (Fs 0.4%), 5 to 10 vol % plagioclase (An 26%), and 5 vol % diopside (Fs 0.9%). In addition, there are minor remnants of metal (Ni 6.35 wt %, Si-free) and troilite (with 5.10 wt % Cr and 1.15 wt % Ti) that have survived extensive terrestrial weathering. The meteorite has a cumulate texture, uniform-size euhedral, prismatic crystals of enstatite (0.3 to 0.4 mm long) with interstitial plagioclase, diopside, troilite, and metal. The enstatite crystals are dominantly disordered and occur in alignments that suggest flow. There are no chondrules or remnants of chondrules. The enstatite crystals contain internal negative crystal voids, which are charactieristic of enstatite achondrites, as well as internal branching submicron rivulet dislocations. The bulk composition is that of an E6 enstatite chondrite, however, it has the texture of a crystal cumulate; achondritic, but unlike that of enstatite achondrites. Glass of a granitic composition occurs mainly in the mesostasis and is compositionally like the glass found inside pyroxene crystals in the Cumberland Falls enstatite achondrite. Happy Canyon is most simply explained as an E6 composition that has melted and reprecipitated at a slightly higher oxidation state, at some depth (> 7 km), possibly in the core volume of a small, asteroidal-size parent body. In terms of classification, it occupies the gap between the recrystallized enstatite chondrites and the igneous, crystalline, unbrecciated enstatite achondrites like Shallowater. Happy Canyon is a new type of enstatite achondrite  相似文献   

WAS THE FORMATION OF LUNAR CRATER GIORDANO BRUNO WITNESSED IN 1178? LOOK AGAIN.     

H.H. Nininger  Glenn I Huss 《Meteoritics & planetary science》1977,12(1):21-25

The assumption that five men witnessed the formation of the lunar crater Giordano Bruno on June 18, 1178, is analyzed. The difficulties inherent in this interpretation are discussed. The only tenable solution — that of a meteor passing before the moon — is presented.  相似文献   

Triggered star formation in bright-rimmed clouds: the Eagle nebula revisited     

J. Miao  Glenn J. White  R. Nelson  M. Thompson  L. Morgan 《Monthly notices of the Royal Astronomical Society》2006,369(1):143-155

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Boundary Condition and Soil Attribute Impacts on Anionic Surfactant Mobility in Unsaturated Soil   总被引：1，自引：0，他引：1  

Barry Allred  Glenn O. Brown 《Ground water》1996,34(6):964-971

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Evidence for frost on Rhea's surface     

Torrence V. Johnson  Glenn J. Veeder  Dennis L. Matson 《Icarus》1975,24(4):428-432

We have observed Rhea (S5) at 1.6 μm and 2.2 μm at Mt. Wilson using the Caltech photometer on the 1.52m and 2.54m telescopes. The infrared spectral reflectances relative to 0.55μm are 0.8 (±0.1 p.e.) at 1.65μm and 0.6 (±0.1 p.e.) at 2.2μm. Such absorption bands in the near infrared are not consistent with spectra of most rocks or minerals; even carbonaceous chondritic materials have nearly flat reflectances over this spectral region. Frosts, however, have strong absorption bands in the 1–3μm region. In particular, the broadband infrared reflectances of Rhea are similar to those of the Galilean satellites Europa (J2) and Ganymede (J3) and also the rings of Saturn (all of which are known from high resolution scans to have water frosts on their surfaces). The broadband photometry does not have sufficient resolution to identify the frost species: but Rhea's low density, high albedo and relatively flat reflectance from 0.3μm to 1.1μm as well as the low infrared reflectances reported here are consistent with the presence of water ice on Rhea's surface.  相似文献   

The thermal structure of Jupiter I. Implications of Pioneer 10 infrared radiometer data     

Glenn S. Orton 《Icarus》1975,26(2):125-141

Temperature profiles for low latitude regions of Jupiter in the 1.0-0.1 bar pressure regime are recovered from Pioneer 10 infrared radiometer data. The temperature near 0.1 bar is 108–117K, depending on the overlying thermal structure assumed. For the South Equatorial Belt, the temperature at 1.0 bar is 170 K, assuming an adiabatic lapse rate in the deep atmosphere. The South Tropical Zone temperature at this level is 155K if pure gaseous absorption is assumed. Alternatively, the temperature is much closer to that in the SEB, assuming the presence of an optically opaque cloud near the 0.6atm (145K) level. Such a cloud presence in the STrZ may be correlated with the visible and 5 micron appearance of the planet and with NH₃ saturation just below this position. The molar fraction of H₂ most consistent with the data is 0.91 ± 0.08. conditional on the perfect validity of the model and the lack of systematic errors in the data. The effective temperatures of the SEB and STrZ are 127.6 and 124.2K, respectively. These temperature profiles are generally consistent with data at other wavelengths and radiative-equilibrium models, but a discrepancy with the preliminary neutral atmosphere inversion of Pioneer 10 radio occultation data remains unexplained.  相似文献   

Reconstructing estuarine conditions: oyster shells as recorders of environmental change, Southwest Florida   总被引：1，自引：0，他引：1  

Donna M. Surge  Kyger C Lohmann  Glenn A. Goodfriend   《Estuarine, Coastal and Shelf Science》2003,57(5-6):737-756

Live-collected shells of the oyster, Crassostrea virginica, contain geochemical records of modern temperature and salinity, so records of prehistoric conditions may be obtained from subfossil shells. Restoration of channelized watersheds in Florida is receiving much attention, and plans for targeted watersheds require information about estuarine conditions before channelization. Lack of historical records necessitates alternative methods to understand pre-disturbance conditions. A ¹⁴C-calibrated, amino-acid geochronology based on racemization of glutamic acid yielded ages ranging from 190–1220 AD and from 1270–1860 AD for subfossil oysters from Blackwater River (near-natural watershed) and for Faka-Union Bay (channelized watershed), respectively. δ¹⁸O and δ¹³C values of subfossil shells from Blackwater River indicate salinity and summer temperatures similar to present. Winter temperatures recorded in shells from 190, 590, 720, and 1050 AD appear 1–5 °C colder than present winter temperatures, whereas the shell from 1220 AD records winter temperatures similar to modern winter temperatures. These temperature shifts may indicate change in climate or natural seasonal variation of winter temperature from year to year. Subfossils from Faka-Union Bay may reflect a complicated hydrology, which cannot be evaluated by isotopic compositions alone and demonstrates the need for development of independent elemental proxies for temperature and salinity. Decreases in δ¹³C from subfossil to modern shells may in part result from CO₂ added to the atmosphere from fossil fuel burning (the Suess effect). Subfossil δ¹³C that is >1‰ more positive than modern shells suggest a change in the dominant carbon sources from terrestrial C₄ or aquatic plants to C₃ plants (mangroves).  相似文献   

Open boundary conditions for regional tidal simulations     

Glenn S. Carter  Mark A. Merrifield   《Ocean Modelling》2007,18(3-4):194-209

The performance of regional tide model simulations is examined in relation to the choice of open boundary conditions. Three barotropic open boundary conditions, clamped elevation, clamped normal velocity, and Flather, give similar results when the prescribed values are exact; however, Flather is much less sensitive to errors in the prescribed values. Of particular concern, it was found that with a phase error between the two boundaries, both the clamped conditions resulted in magnitude errors in the unclamped variable (although the simulation remained stable).A modified flow relaxation scheme for the depth-varying prognostic variables is presented. This implementation allows the transmission of a range of vertical modes while retaining realistic topography at the boundary. It was found to be an excellent internal tide boundary condition in tests comparing simulations of different domain length encompassing a ridge and sloping bottom, and in a comparison to an analytical solution. Mass is conserved without any artificial volume constraint.  相似文献   

The effects of petroleum hydrocarbons on lipid metabolism and energetics of larval development and metamorphosis in the american lobster (homarus americanus Milne Edwards)     

Judith M. Capuzzo  Bruce A. Lancaster  Glenn C. Sasaki 《Marine environmental research》1984,14(1-4)

In studies with larval stages of the American lobster (Homarus americanus) exposed to a sublethal concentration of South Louisiana crude oil, the normal patterns of lipid storage, utilization and synthesis during larval development and metamorphosis were altered with oil exposure. Increased rates of protein catabolism, delayed molting and reduced growth were also evident among oil-exposed lobster larvae and suggest either deficiency or immobilization of lipid reserves. From analyses of lipid class composition of control and oil-exposed lobster larvae, it is evident that oil-exposed larvae have consistently lower levels of triacylglycerols (the major energy store) and higher levels of sterols than control larvae. Decreased ratios of non-essential fatty acids (both saturated and unsaturated) and increased ratios of essential fatty acids were detected in the neutral lipid pools of oil-exposed larvae that suggest both decreased storage of fatty acids in energy reserves and decreased mobilization of essential fatty acids into phospholipid pools. The fatty acid distribution in the phospholipid pools of oil-exposed larvae, however, varied little from control values and reflects a tendency to preserve the integrity of these structural lipids. Increases in sterol levels may be related to decreased mobilization of cholesterol or other sterols and/or transformation of cholesterol into metabolic pathways including the biosynthesis of ecdysterone.Oil-exposed animals contained trace quantities of benzene, thiophene, toluene, alkylcyclohexane and alkylbenzenes, detected with GC-MS analyses. No naphthalene, dimethylnaphthalene, higher molecular weight aromatics or their phenolic derivatives were detected; their absence may be related to either the detection limits of the methodology used or extremely rapid metabolism and turnover of these components. Alterations in lipid metabolism may account for the developmental and energetic abnormalities observed in marine crustaceans. It cannot be ruled out, however, that decreased lipid utilization, synthesis and mobilization may be a defense mechanism against incorporating lipophilic components of petroleum hydrocarbons in metabolic pathways, and that disruption in energetics and development is a consequence of the reduction in energy available for growth and molting.  相似文献