bluuebunny/crossref_metadata_2025 huggingface dataset:
Human cyclin B3
Authors: Tschöp Katrin , Müller Gerd A. , Grosche Jens , Engeland Kurt
Published: March 2006

Cyclins form complexes with cyclin‐dependent kinases. By controlling activity of the enzymes, cyclins regulate progression through the cell cycle. A‐ and B‐type cyclins were discovered due to their distinct appearance in S and G2 phases and their rapid proteolytic destruction during mitosis. Transition from G2 to mitosis is basically controlled by B‐type cyclins. In mammals, two cyclin B proteins are well characterized, cyclin B1 and cyclin B2. Recently, a human cyclin B3 gene was described. In contrast to the expression pattern of other B‐type cyclins, we find cyclin B3 mRNA expressed not only in S and G2/M cells but also in G0 and G1. Human cyclin B3 is expressed in different variants. We show that one isoform remains in the cytoplasm, whereas the other variant is translocated to the nucleus. Transport to the nucleus is dependent on three autonomous nonclassical nuclear localization signals that where previously not implicated in nuclear translocation. It had been shown that cyclin B3 coimmunoprecipitates with cdk2; but this complex does not exhibit any kinase activity. Furthermore, a degradation‐resistant version of cyclin B3 can arrest cells in G1 and G2. Taken together with the finding that cyclin B3 mRNA is not only expressed in G2/M but is also detected in significant amounts in resting cells and in G1 cells. This may suggest a dominant‐negative function of human cyclin B3 in competition with activating cyclins in G0 and the G1 phase of the cell cycle.
Evolutionary origin and divergence of PQRFamide peptides and LPXRFamide peptides in the RFamide peptide family
Authors: Osugi Tomohiro , Ukena Kazuyoshi , Sower Stacia A. , Kawauchi Hiroshi , Tsutsui Kazuyoshi
Published: March 2006

Among the RFamide peptide groups, PQRFamide peptides, such as neuropeptide FF (NPFF) and neuropeptide AF (NPAF), share a common C‐terminal Pro‐Gln‐Arg‐Phe‐NH2motif. LPXRFamide (X = L or Q) peptides, such as gonadotropin‐inhibitory hormone (GnIH), frog growth hormone‐releasing peptide (fGRP), goldfish LPXRFamide peptide and mammalian RFamide‐related peptides (RFRPs), also share a C‐terminal Leu‐Pro‐Leu/Gln‐Arg‐Phe‐NH2motif. Such a similar C‐terminal structure suggests that these two groups may have diverged from a common ancestral gene. In this study, we sought to clarify the evolutionary origin and divergence of these two groups, by identifying novel RFamide peptides from the brain of sea lamprey, one of only two extant groups of the oldest lineage of vertebrates, Agnatha. A novel lamprey RFamide peptide was identified by immunoaffinity purification using the antiserum against LPXRFamide peptide. The lamprey RFamide peptide did not contain a C‐terminal LPXRFamide motif, but had the sequence SWGAPAEKFWMRAMPQRFamide (lamprey PQRFa). A cDNA of the precursor encoded one lamprey PQRFa and two related peptides. These related peptides, which also had the C‐terminal PQRFamide motif, were further identified as mature endogenous ligands. Phylogenetic analysis revealed that lamprey PQRFamide peptide precursor belongs to the PQRFamide peptide group.In situhybridization demonstrated that lamprey PQRFamide peptide mRNA is expressed in the regions predicted to be involved in neuroendocrine and behavioral functions. This is the first demonstration of the presence of RFamide peptides in the agnathan brain. Lamprey PQRFamide peptides are considered to have retained the most ancestral features of PQRFamide peptides.
The antibody to GD3 ganglioside, R24, is rapidly endocytosed and recycled to the plasma membrane via the endocytic recycling compartment
Authors: Iglesias‐Bartolomé Ramiro , Crespo Pilar M. , Gomez Guillermo A. , Daniotti Jose L.
Published: March 2006

Gangliosides are sialic acid‐containing glycosphingolipids present on mammalian plasma membranes, where they participate in cell‐surface events such as modulation of growth factor receptors and cell‐to‐cell and cell‐to‐matrix interactions. Antibodies to gangliosides have been associated with a wide range of clinically identifiable acute and chronic neuropathy syndromes. In addition, antibodies to tumor‐associated gangliosides are being used as therapeutic agents. Their binding to and release from cell membranes and intracellular destinations have not so far been extensively examined. In this study, we characterized in both GD3 ganglioside‐expressing Chinese hamster ovary (CHO)‐K1 and SK‐Mel 28 melanoma cells the intracellular trafficking and subcellular localization of the mouse monoclonal antibody to GD3, R24. By biochemical techniques and detailed confocal microscopic analysis, we demonstrate that the GD3–R24 antibody complex is rapidly and specifically internalized by a dynamin 2‐independent pathway and then accumulates in the endocytic recycling compartment. In addition, we show that the R24 antibody exits the recycling compartment en route to the plasma membrane by a dynamin 2‐dependent pathway sensitive to brefeldin A and monensin. Taken together, our results indicate that the GD3–R24 complex is endocytosed in GD3‐expressing cells, accumulates in the recycling endosome, and is transported back to the plasma membrane via a route that involves clathrin‐coated vesicles.
EFFECTIVENESS OF CATEGORY AND LINE SCALES TO CHARACTERIZE CONSUMER PERCEPTION OF FRUITY FERMENTED FLAVOR IN PEANUTS
Authors: GREENE J.L. , BRATKA K.J. , DRAKE M.A. , SANDERS T.H.
Published: March 2006

Fruity fermented (FF) flavor is a common off‐flavor in peanuts resulting from high‐temperature curing. The 9‐point hedonic scale is the most widely used scale to determine consumer acceptance; however, research has indicated that line scales may provide equal reliability and greater sensitivity. The objectives of this study were to characterize consumer perception of FF flavor in peanuts and to compare the effectiveness of the two scale types. Consumers (n = 208) evaluated control (no FF), low‐intensity (1.0) FF and high‐intensity (3.0) FF peanut pastes for the strength/intensity of roasted peanut flavor (RPF), sweet taste (ST), fresh peanut flavor (FPF) and overall liking (OV) using randomly assigned ballots. Sensitivity in defining consumer perception of off‐flavor in peanuts was greater with use of line scales than with the hedonic scale. The line scale indicated that FF flavor in peanuts, even at low intensity, negatively impacted OV and further identified significantly lower RPF and FPF perception by consumers. The hedonic scale identified only a difference in FPF and was not sensitive enough to show a difference in OV.
SENSORY EXPECTATIONS OF CHILDREN FROM DIFFERENT HOUSEHOLD INCOMES FOR A BRANDED CONFECTIONARY PRODUCT
Authors: SOSA MIRIAM , HOUGH GUILLERMO
Published: March 2006

The influence of brand and price on the sensory acceptability of alfajor (an individual cake covered in chocolate) among children from different household incomes was measured. Two brands of alfajores, “cheap” and “expensive,” were used. A total of 120 children, half from low‐income households (LI) and half from medium‐ to high‐income households (M–HI), participated in the study. They tasted the alfajores in three conditions: blind, package‐alone and package + product. The LI children were not influenced by brand. For the M–HI children, an assimilation effect was observed. The findings highlight the importance of socioeconomic factors in sensory expectation. In the blind condition, if the price is very high, no matter how much a child likes an alfajor he/she will not buy it. If the price is low, the overall liking will highly influence the choice. Implications of results for manufacturers, money providers and nutritional education agencies are discussed.
SENSORY DESCRIPTIVE ANALYSIS OF URUGUAYAN TANNAT WINE: CORRELATION TO QUALITY ASSESSMENT
Authors: VARELA PAULA , GÁMBARO ADRIANA
Published: March 2006

Tannat (Vitis vinifera L. cv. Tannat) was the main grape variety to be established in Uruguay, being the only country in the Americas where this grape is commonly found. Because of its small cultivation in the world, this variety has not been thoroughly studied, hence, considerable research and development on this variety is still needed. The aims of this study were to obtain the aroma and taste profiles of Tannat red wine by means of descriptive analysis and to correlate the quantitative sensory data to the quality assessment obtained through a small panel of fine wine consumers. The correlations obtained resulted in a useful tool in Uruguayan Tannat wine development. Results showed that an increment in yeasty, burned and earthy aromas resulted in lower quality scores, while high intensities of dried fruit, phenolic and berry aromas are desirable in this fine wine variety. As far as taste is concerned, astringency positively influences quality evaluation of flavor (attack, evolution and persistence), body and overall quality.
SENSORY PROPERTIES OF WILD AND AQUACULTURED SOUTHERN FLOUNDER (PARALICHTHYS LETHOSTIGMA)
Authors: DRAKE S.L. , DRAKE M.A. , DANIELS H.V. , YATES M.D.
Published: March 2006

There is considerable interest in the aquaculture of southern flounder,Paralichthys lethostigma, because of its worldwide market appeal, high market value and ability to grow in fresh or brackish water. This study was conducted to identify and define sensory properties of wild (WF), freshwater farm‐raised (FFF) and saltwater farm‐raised (SFF) southern flounder. In addition, consumer acceptance of these three sources of southern flounder was determined. A defined sensory lexicon for southern flounder (appearance, flavor, texture) was identified. Descriptive sensory differences were documented among the three types of flounder (P < 0.05). FFF flounder was differentiated by an earthy flavor. WF and SFF flounder were characterized by medicinal and fresh fish flavors, respectively. Consumer acceptance scores for SFF were significantly higher in all attributes compared with WF or FFF flounder (P < 0.05). Consumers preferred SFF > WF > FFF flounder (P < 0.05). SFF flounder may be a viable alternative to WF flounder.
Ground Water Occurrence and Contributions to Streamflow in an Alpine Catchment, Colorado Front Range
Authors: Clow D.W. , Schrott L. , Webb R. , Campbell D.H. , Torizzo A. , Dornblaser M.
Published: March 2006

Ground water occurrence, movement, and its contribution to streamflow were investigated in Loch Vale, an alpine catchment in the Front Range of the Colorado Rocky Mountains. Hydrogeomorphologic mapping, seismic refraction measurements, and porosity and permeability estimates indicate that talus slopes are the primary ground water reservoir, with a maximum storage capacity that is equal to, or greater than, total annual discharge from the basin (5.4 ± 0.8 × 106 m3). Although snowmelt and glacial melt provide the majority of annual water flux to the basin, tracer tests and gauging along a stream transect indicate that ground water flowing from talus can account for ≥75% of streamflow during storms and the winter base flow period. The discharge response of talus springs to storms and snowmelt reflects rapid transmittal of water through coarse debris at the talus surface and slower release of water from finer‐grained sediments at depth.

Ice stored in permafrost (including rock glaciers) is the second largest ground water reservoir in Loch Vale; it represents a significant, but seldom recognized, ground water reservoir in alpine terrain. Mean annual air temperatures are sufficiently cold to support permafrost above 3460 m; however, air temperatures have increased 1.1° to 1.4°C since the early 1990s, consistent with long‐term (1976–2000) increases in air temperature measured at other high‐elevation sites in the Front Range, European Alps, and Peruvian Andes. If other climatic factors remain constant, the increase in air temperatures at Loch Vale is sufficient to increase the lower elevational limit of permafrost by 150 to 190 m. Although this could cause a short‐term increase in streamflow, it may ultimately result in decreased flow in the future.
Hydrological Dynamics of the Panola Mountain Research Watershed, Georgia
Authors: Peters Norman E. , Freer James , Aulenbach Brent T.
Published: March 2006

Relations between stormflow characteristics and soil‐moisture content, water table elevation in wells along several transects perpendicular to the stream, and precipitation were evaluated for the Panola Mountain Research Watershed, Georgia, from water years 1986 through 2001 to refine the conceptualization of streamflow generation, including the relations between ground water dynamics and streamflow. For 759 rainstorms during 16 water years, stormflow water yield correlates best with maximum soil‐moisture content and with maximum water table elevation; the relations are linear above thresholds for the entire period and vary by season. For moderate to large rainstorms, relations among wetness parameters and stormflow water yield are better (less scatter) and more consistent when the watershed is seasonally wet than when the watershed is dry. During rainstorms, soil‐moisture content (minimum or maximum) is highly correlated among soil depths and with water table elevations. The soil‐moisture measurements were made at one site at the base of a hillslope, and the values at any depth are likely to vary spatially and with respect to timing, other landscape positions, and soil types. Stormflow water yield is linearly related to soil‐moisture content at the deepest location (70 cm) above 37% volumetric moisture content, which occurs ∼20% of the time. Maximum water table elevation is linearly related to maximum soil‐moisture content above a threshold, and the soil‐moisture threshold increases with upslope position; the soil‐moisture threshold for flow to occur at a trench hillslope site is 41%, which occurs <0.5% of the time. The general relations among streamflow, soil moisture, and water table response are attributed to variable source areas, particularly the ground water contribution from a riparian zone aquifer ≤5 m thick that expands as the watershed becomes wetter.
Where Does the Ground Water in Small Watersheds Come From?
Authors: Winter Thomas C. , Rosenberry Donald O. , LaBaugh James W.
Published: March 2006

Surface water and ground water watersheds commonly do not coincide. This condition is particularly relevant to understanding biogeochemical processes in small watersheds, where detailed accounting of water and solute fluxes commonly are done. Ground water watersheds are not as easily defined as surface watersheds because (1) they are not observable from land surface; (2) ground water flow systems of different magnitude can be superimposed on one another; and (3) ground water divides may move in response to dynamic recharge and discharge conditions. Field studies of relatively permeable terrain in Wisconsin, Minnesota, and Nebraska indicate that lakes and wetlands in small watersheds located near the lower end of extensive ground water flow systems receive ground water inflow from shallow flow systems that extend far beyond their surface watershed, and they may also receive ground water inflow from deeper regional flow systems that pass at depth beneath local flow systems. Field studies of mountainous terrain that have low‐permeability deposits in New Hampshire and Costa Rica also indicate that surface water bodies receive ground water inflow from sources beyond their local surface watersheds. Field studies of lakes and wetlands in North Dakota, Nebraska, and Germany indicate that ground water divides move in response to changing climate conditions, resulting in a variable source of ground water inflow to those surface water bodies.
Enhanced Submarine Ground Water Discharge from Mixing of Pore Water and Estuarine Water
Authors: Martin Jonathan B. , Cable Jaye E. , Swarzenski Peter W. , Lindenberg Mary K.
Published: March 2006

Submarine ground water discharge is suggested to be an important pathway for contaminants from continents to coastal zones, but its significance depends on the volume of water and concentrations of contaminants that originate in continental aquifers. Ground water discharge to the Banana River Lagoon, Florida, was estimated by analyzing the temporal and spatial variations of Cl− concentration profiles in the upper 230 cm of pore waters and was measured directly by seepage meters. Total submarine ground water discharge consists of slow discharge at depths > ∼70 cm below seafloor (cmbsf) of largely marine water combined with rapid discharge of mixed pore water and estuarine water above ∼70 cmbsf. Cl− profiles indicate average linear velocities of ∼0.014 cm/d at depths > ∼70 cmbsf. In contrast, seepage meters indicate water discharges across the sediment‐water interface at rates between 3.6 and 6.9 cm/d. The discrepancy appears to be caused by mixing in the shallow sediment, which may result from a combination of bioirrigation, wave and tidal pumping, and convection. Wave and tidal pumping and convection would be minor because the tidal range is small, the short fetch of the lagoon limits wave heights, and large density contacts are lacking between lagoon and pore water. Mixing occurs to ∼70 cmbsf, which represents depths greater than previously reported. Mixing of oxygenated water to these depths could be important for remineralization of organic matter.
Advection Within Shallow Pore Waters of a Coastal Lagoon, Florida
Authors: Cable Jaye E. , Martin Jonathan B. , Swarzenski Peter W. , Lindenberg Mary K. , Steward Joel
Published: March 2006

Ground water sources can be a significant portion of a local water budget in estuarine environments, particularly in areas with high recharge rates, transmissive aquifers, and permeable marine sediments. However, field measurements of ground water discharge are often incongruent with ground water flow modeling results, leaving many scientists unsure which estimates are accurate. In this study, we find that both measurements and model results are reasonable. The difference between estimates apparently results from the sources of water being measured and not the techniques themselves. In two locations in the Indian River Lagoon estuarine system, we found seepage meter rates similar to rates calculated from the geochemical tracers 222Rn and 226Ra. Ground water discharge rates ranged from 4 to 9 cm/d using seepage meters and 3 to 20 cm/d using 222Rn and 226Ra. In contrast, in comparisons to other studies where finite element ground water flow modeling was used, much lower ground water discharge rates of ∼0.05 to 0.15 cm/d were estimated. These low rates probably represent discharge of meteoric ground water from land‐recharged aquifers, while the much higher rates measured with seepage meters, 222Rn, and 226Ra likely include an additional source of surface waters that regularly flush shallow (< 1 m depth) sediments. This resultant total flow of mixed land‐recharged water and recirculated surface waters contributes to the total biogeochemical loading in this shallow estuarine environment.
Hydrogeologic Setting and Ground Water Flow Beneath a Section of Indian River Bay, Delaware
Authors: Krantz David E. , Manheim Frank. T. , Bratton John F. , Phelan Daniel J.
Published: March 2006

The small bays along the Atlantic coast of the Delmarva Peninsula (Delaware, Maryland, and Virginia) are a valuable natural resource, and an asset for commerce and recreation. These coastal bays also are vulnerable to eutrophication from the input of excess nutrients derived from agriculture and other human activities in the watersheds. Ground water discharge may be an appreciable source of fresh water and a transport pathway for nutrients entering the bays. This paper presents results from an investigation of the physical properties of the surficial aquifer and the processes associated with ground water flow beneath Indian River Bay, Delaware. A key aspect of the project was the deployment of a new technology, streaming horizontal resistivity, to map the subsurface distribution of fresh and saline ground water beneath the bay. The resistivity profiles showed complex patterns of ground water flow, modes of mixing, and submarine ground water discharge. Cores, gamma and electromagnetic‐induction logs, and in situ ground water samples collected during a coring operation in Indian River Bay verified the interpretation of the resistivity profiles. The shore‐parallel resistivity lines show subsurface zones of fresh ground water alternating with zones dominated by the flow of salt water from the estuary down into the aquifer. Advective flow produces plumes of fresh ground water 400 to 600 m wide and 20 m thick that may extend more than 1 km beneath the estuary. Zones of dispersive mixing between fresh and saline ground water develop on the upper, lower, and lateral boundaries of the plume. The plumes generally underlie small incised valleys that can be traced landward to streams draining the upland. The incised valleys are filled with 1 to 2 m of silt and peat that act as a semiconfining layer to restrict the downward flow of salt water from the estuary. Active circulation of both the fresh and saline ground water masses beneath the bay is inferred from the geophysical results and supported by geochemical data.
Studying Ground Water Under Delmarva Coastal Bays Using Electrical Resistivity
Authors: Manheim Frank T. , Krantz David E. , Bratton John F.
Published: March 2006

Fresh ground water is widely distributed in subsurface sediments below the coastal bays of the Delmarva Peninsula (Delaware, Maryland, and Virginia). These conditions were revealed by nearly 300 km of streamer resistivity surveys, utilizing a towed multichannel cable system. Zones of high resistivity displayed by inversion modeling were confirmed by vibradrilling investigations to correspond to fresh ground water occurrences. Fresh water lenses extended from a few hundred meters up to 2 km from shore. Along the western margins of coastal bays in areas associated with fine‐grained surficial sediments, high‐resistivity layers were widespread and were especially pronounced near tidal creeks. Fresh ground water layers were less common along the eastern barrier‐bar margins of the bays, where sediments were typically sandy. Mid‐bay areas in Chincoteague Bay, Maryland, did not show evidence of fresh water. Indian River Bay, Delaware, showed complex subsurface salinity relationships, including an area with possible hypersaline brines. The new streamer resistivity system paired with vibradrilling in these investigations provides a powerful approach to recovering information required for extension of hydrologic modeling of shallow coastal aquifer systems into offshore areas.
Effects of Aquifer Travel Time on Nitrogen Transport to a Coastal Embayment
Authors: Colman John A. , Masterson John P. , Pabich Wendy J. , Walter Donald A.
Published: March 2006

Effects of aquifer travel time on nitrogen reaction and loading to Popponesset Bay, a eutrophic coastal embayment on western Cape Cod, Massachusetts, are evaluated through hydrologic analysis of flow and transport. Approximately 10% of the total nitrogen load to the embayment is intercepted by fresh water ponds and delivered to the coast by connecting streams. For the nitrogen load not intercepted by ponds, we compare two steady‐state methods of analyzing nitrogen loss in the aquifer, one using a constant‐loss factor and the other time‐dependent loss rates. The constant‐loss method, which assumes that all similar land uses have the same per unit area loading rate to surface water regardless of location within the watershed, predicts that 42% of the nonpond watershed nitrogen load originated within the zero to 2 yr time‐of‐travel zone, which is 40% of the contributing area. The time‐of‐travel loss method calculates loss rates based on aquifer travel times and denitrification reaction kinetics, evaluated separately for carbon‐unlimited and carbon‐limited cases. Time‐of‐travel loss calculations for percent of nonpond load that originated within the area of < 2 yr aquifer residence time are 64% when carbon is not limiting, but only 49% when carbon limitation is included, not greatly different from the constant‐loss method. A feature of the kinetics used is that carbon (and the denitrified nitrogen) is lost rather quickly in the aquifer travel path, after which carbon limitation stops denitrification altogether. Carbon limitation causes the time‐of‐travel loss model to approximate the constant‐loss model such that in most of the watershed, a nearly constant fraction of the nitrogen input is lost in both models.
Ground Water Recharge and Discharge in the Central Everglades
Authors: Harvey Judson W. , Krupa Steven L. , Krest James M.
Published: March 2006

Rates of ground water recharge and discharge are not well known in the central Everglades. Here we report estimates of ground water recharge and discharge at 15 sites in the Everglades Nutrient Removal Project and in Water Conservation Area 2A (WCA‐2A), along with measurements of hydraulic properties of peat at 11 sites. A simple hydrogeologic simulation was used to assess how specific factors have influenced recharge and discharge. Simulations and measurements agreed that the highest values of recharge and discharge occur within 600 m of levees, the result of ground water flow beneath levees. There was disagreement in the interior wetlands of WCA‐2A (located > 1000 m from levees) where measurements of recharge and discharge were substantially higher than simulated fluxes. A five‐year time series (1997 to 2002) of measured fluxes indicated that recharge and discharge underwent reversals in direction on weekly, monthly, and annual timescales at interior sites in WCA‐2A. Ground water discharge tended to occur during average to moderately dry conditions when local surface water levels were decreasing. Recharge tended to occur during moderately wet periods or during very dry periods just as water levels began to increase following precipitation or in response to a pulse of surface water released from water‐control structures by water managers. Discharge also tended to occur at sites in the wetland interior for ∼1 week preceding the arrival of the surface water pulse. We conclude that ground water recharge and discharge vary cyclically in the interior wetlands of the central Everglades, driven by the differential responses of surface water and ground water to annual, seasonal, and weekly trends in precipitation and operation of water‐control structures.
DEPOSITIONAL AND DIAGENETIC HISTORY OF THE KERENDAN CARBONATE PLATFORM, OLIGOCENE, CENTRAL KALIMANTAN, INDONESIA
Authors: Saller A. H. , Vijaya S.
Published: March 2006

The Kerendan carbonate platform (Oligocene Berai Limestone) covers a subsurface area measuring approximately 11 by 16 km in the westernmost Kutei Basin, Central Kalimantan. Aggradation of the Kerendan platform occurred during a major Oligocene transgression, and is contemporaneous with aggradation and backstepping of the Barito shelf margin which was located approximately 30 km to the south. The Kerendan platform is approximately 1,000 m thick, and comprises three aggrading seismic sequences identified by the downlap of basinal strata at the platform margin and downlap of transgressive strata within the platform. Carbonate deposition started in the Late Eocene, and ended when the upper limestone sequence drowned and was covered with shale in the Late Oligocene (approximately 28.6 Ma). Three depositional areas can be distinguished in seismic sections: (1) a platform interior (lagoon); (2) a slightly raised platform rim (1–2 km wide); and (3) a basinward‐dipping platform margin and slope. The margin of the platform is identified by inflections on the seismic profiles where the relatively flat platform top begins to slope basinward.

Depositional models from outcrops combined with core from three Kerendan wells were used to extrapolate depositional facies onto the seismically‐defined platform. Platform‐interior (lagoon) facies consist largely of fossiliferous wackestones and packstones, and porosities are generally lower than 5%. The platform rim is characterized by interbedded bioclastic wackestones, packstones, grainstones and boundstones, with grainstones increasing toward the platform margin. Porosity preferentially occurs in packstones, grainstones and boundstones. The platform‐rim deposits have greater porosity (5–13%) than the platform interior because the platform run is more grainstone‐rich, and because acidic waters compacting out of basinal shales concentrated dissolution near the platform margin. Pore types include vuggy porosity, microporosity within grains, and intercrystalline porosity in dolomite in the upper part of the platform rim. Different pore types have resulted in variable but locally very high permeabilities (greater than 100 mD). Permeabilities decrease with depth as vuggy pores decrease, and microporosity becomes dominant.
RESERVOIR ARCHITECTURE IN A TERMINAL ALLUVIAL PLAIN: AN OUTCROP ANALOGUE STUDY (UPPER TRIASSIC, SOUTHERN GERMANY) PART II: CYCLICITY, CONTROLS AND MODELS
Authors: Hornung J. , Aigner T.
Published: March 2006

This outcrop analogue study investigates Triassic fluvial sandstones of the Stubensandstein Formation which were deposited on a terminal alluvial plain under semi‐arid to sub‐humid climatic conditions in the land‐locked South German Keuper Basin. The Stubensandstein may serve as an analogue for reservoir units in comparable continental basins. Data came from studies of 13 large sandpits, together with a subsurface database supported by three well‐log clusters (comprising up to 20 boreholes) and four single wells.

Lithofacies types vary along a palaeogeographical gradient from proximal erosion and non‐deposition to fluvial bed‐load, to distal suspended‐load deposits and finally to playas with lacustrine carbonates.

Within a three‐fold hierarchy of cyclicity, meso‐ and macro‐scale cycles could be correlated regionally using an approach based on stratigraphic base‐level changes.

The observed sedimentary patterns, together with palaeosol types, their stable isotope signals and palynological data, indicate that palaeoclimatic fluctuations exerted the principal control on stratigraphic architecture and cyclicity. Progradation of sand wedges into the basin occurred while climate was arid but becoming more humid. As playa lake levels rose, the alluvial sands retrograded. Shorter and longer‐term palaeoclimatic fluctuations caused systematic changes in reservoir and seal geometries, and in the extent and interconnectedness of sandbodies. Thus, a knowledge of the overall palaeoclimatic trends in comparable continental basins may allow predictions to be made concerning the regional reservoir architecture.

Outcrop data were used to generate static reservoir models of sandbody architecture in subsurface well log data sets. A stochastic facies and poro‐perm simulation was run and calibrated with outcrop data. Different stratigraphic levels could be reproduced, as could the scouring and interbedding of the different fluvial systems.
RESERVOIR POTENTIAL OF CRETACEOUS PLATFORM‐MARGIN BRECCIAS, CENTRAL ITALIAN APENNINES
Authors: Casabianca D. , Bosence D. , Beckett D.
Published: March 2006

In this paper, we report on the characteristics of sedimentary breccias derived from, and deposited adjacent to, the Cretaceous Maiella carbonate platform in central Italy. Previous work has interpreted the northern platform margin to have been inherited from Early Jurassic rifting, and to have remained tectonically passive throughout the Cretaceous. However, our field studies show that the platform margin was segmented by north‐south oriented normal faults in the Late Cretaceous. Thick breccias composed of lithoclastic rudstones and floatstones were derived from the collapse of the shelf margin, and were deposited as rock avalanche and debris flow deposits in hangingwall depocentres.

Four breccia units (thicknesses up to 250m, 130m, 60m and 20m) were mapped and studied in detail. Clasts consist of shallow‐water bioclastic limestones; textures vary within each breccia unit from rudstones in the bottom two‐thirds to floatstones above. Vuggy, late stage dissolution porosity is present throughout each unit, and probably developed in a meteoric environment after Pliocene thrusting and exhumation. Much earlier diagenesis, associated with a Late Cretaceous shallow‐marine to meteoric environment, generated the mouldic and intergranular porosity observed in the rudstones. The skeletal floatstones display biomouldic porosity which has likewise been preserved since the Late Cretaceous.

Bulk porosity volumes have been estimated for three of the breccias at the time of expected hydrocarbon charge (Miocene‐Pliocene): they range between 72 × 106 and 42 × 106 m3. Oil seepage from these breccias can be observed at the present day in outcrops near to the study area, indicating that migration and charge are still active.

The significance of the breccias as potential reservoirs is that high‐porosity platform margin facies clasts were transported into a depositional environment which would otherwise have been occupied by low‐porosity slope facies. This extends the platform margin reservoir fairway beyond the defined platform edge.
DETERMINATION OF PALAEOSTRESSES FROM MESOSCALE SHEAR FRACTURES IN CORE SAMPLES USING THE MULTI‐INVERSE METHOD
Authors: Yamada Y. , Yamaji A.
Published: March 2006

Palaeostress reconstruction is the key to quantitative characterization of fractured hydrocarbon reservoirs. In order to calculate the palaeostresses responsible for fault activity, faults in oriented core samples can be analysed and the optimal stresses can then be determined from fault‐slip data in a least‐squares sense. Many fractured reservoir rocks, however, include faults generated during a number of different tectonic phases. In these cases, the optimal stresses can be determined for subgroups of faults which are considered to be of approximately the same age. The difficulty with this is that criteria for accurate age‐dating are often absent, especially from core samples.

Recently, the so‐called “multi‐inverse” method has been proposed to address this problem. This is a numerical technique for separating palaeostresses within a heterogeneous fault assemblage in the absence of a priori information on the faults’relative ages. In this paper, we apply the method to eighteen faults in two short (9m) cores from an exploration well in Hokkaido, northern Japan. The cores came from a fractured hydrocarbon reservoir and were oriented by correlation with borehole images. Core lithologies included massive Cretaceous basalts in which there was no layering which would show fault offsets; for these samples, we determined the sense of shear by studying asymmetric microstructures on the fault surfaces. The results show that the rocks have experienced six different stress regimes. In general, these are compatible with the tectonic history of the study area as inferred from the regional stratigraphy and from macroscale geological structures.

These results show that the multi‐inverse method can be used to extract palaeostress data from cores, thereby providing information which will assist with the exploration of (and production from) fractured hydrocarbon reservoirs.
GEOLOGY AND GEOCHEMISTRY OF SOURCE ROCKS IN THE QAIDAM BASIN, NW CHINA
Authors: Qiang Jin , Ming Zha , Zhen Liu , XianZhi Gao , Dehua Peng , Lamei Lin
Published: March 2006

In this paper, we discuss the organic geochemistry of source rocks in the Qaidam Basin, NW China, using data generated during a recent four‐year study. This study addressed some basic problems concerning petroleum systems in the basin, problems which persist despite some five decades of exploration. We show that three separate source rocks are present and these are distinct in terms of both age and depositional facies and also geographical distribution.

The oldest source rocks are Lower Jurassic fresh‐water lacustrine deposits which are generally confined to northern Qaidam. These are currently thermally mature or highly mature and have generated the oils, condensates and gases which have been discovered in Jurassic and Tertiary reservoirs in the North Qaidam area.

By contrast, Tertiary source rocks were deposited in saline lakes. Previous studies have shown that they are characterized by low TOC values (0.2–0.6%). However, we found Tertiary source rocks with TOC > 1.0%; these were deposited in hypersaline lakes around the Manya Depression in western Qaidam. These source rocks have probably generated the oils at fields recently discovered in the western part of the basin.

The youngest (gas‐prone) source rocks in the basin are Quaternary. These were deposited in saline lakes in the east and central parts of the basin and are thermally immature. However they are thought to have generated the large volumes of biogenic gas which are present in Quaternary reservoirs.
SECOND‐ORDER SEQUENCE STRATIGRAPHY OF THE PALAEOZOIC OF NORTH AFRICA
Authors: Carr I. D.
Published: March 2006

A synthesis of the sedimentology and sequence stratigraphy of the Palaeozoic succession of North Africa is presented. Two chronostratigraphic correlation panels have been constructed at roughly right angles to each other across North Africa, in WNW‐ESE and NNW‐SSE orientations. The panels illustrate the way in which sedimentology and hydrocarbon geology vary across the continent through time. The Palaeozoic succession is divided into five second‐order sequences (NA 1, Early Cambrian to Late Ordovician; NA 2, Late Ordovician to Late Silurian; NA 3, Devonian; NA 4, Carboniferous; NA 5, Permian), with sequence boundaries, maximum flooding surfaces and systems tracts being defined for NA 1 to NA 4. Palaeogeographic reconstructions for the North African region from the Cambrian to the Carboniferous are illustrated, and a sea‐level curve based on the panels and palaeogeographic reconstructions is compared to other published sea‐level curves. The proximity of the North African region to the South Pole during the Palaeozoic and its relative tectonic stability suggest that sea‐level curves derived from the area should closely reflect Palaeozoic glacio‐eustasy. This study may be used to investigate the occurrence of reservoir, seal and source rocks away from areas of data control, and is intended to provide a useful framework for future third‐order studies.
TUNNEL VALLEYS AND DENSITY FLOW PROCESSES IN THE UPPER ORDOVICIAN GLACIAL SUCCESSION, ILLIZI BASIN, ALGERIA: INFLUENCE ON RESERVOIR QUALITY
Authors: Hirst J. P. P. , Benbakir A. , Payne D. F. , Westlake I. R.
Published: March 2006

Upper Ordovician syn‐glacial deposits form a gas reservoir at the Tiguentourine field, Illizi Basin, Algeria. The reservoir geology of these glacial deposits has been investigated with the objective of understanding the widely varying thickness of the sequence and the controls on reservoir quality.

A general depositional model was developed following a review of outcrops in the Tassili N'Ajjer region, some 200km south of Tiguentourine. In these outcrops, elongate tunnel valleys were observed to be incised into the subglacial surface, and these were interpreted to have been formed by subglacial meltwater flows. The isopach map of the Tiguentourine field syn‐glacial sequence, derived from well penetrations and a 3D seismic survey, indicates there were two elongate depressions analogous to, but broader than, the tunnel valleys observed at outcrop.

The sedimentary rocks encountered at outcrop and in the subsurface were broadly similar. Initial sedimentation in the tunnel valleys typically comprised medium‐ to coarsegrained, structured sandstones. These were interpreted as the deposits of glaciofluvial currents flowing along the tunnel valleys. They were succeeded by a range of density flow deposits (muddy and sandy debrites, high‐ and low‐density turbidites). In the outcrops, the turbidites are seen to evolve upwards from an amalgamated sheet complex to sinuous channel forms. Long wavelength (>2m), low amplitude, symmetrical dunes were noted in these high‐density turbidites; they were interpreted to be the products of sustained, possibly hyperpycnal, turbidity currents. In the subsurface, pelagic deposits with graptolites were recorded towards the top of the succession indicating a glacial‐marine environment. At its maximum extent, the ice is believed to have been grounded on the continental shelf. The synglacial succession in the south Illizi Basin was interpreted as a product of glacial retreat, with the hardground at the top of the sequence probably the result of isostatic uplift.
A RE‐CONSIDERATION OF THE “OIL WINDOW” FOR HUMIC COAL AND KEROGEN TYPE III SOURCE ROCKS
Authors: Petersen H. I.
Published: March 2006

Based on natural data‐sets and several hydrous‐pyrolysis experiments on immature humic coals, the conventional “oil window” (0.5–0.6%R0 to 1.3–1.35%R0) for humic coals is re‐considered. A worldwide coal data‐set comprising coals of Carboniferous ‐ Tertiary age and having vitrinite reflectances from 0.32%R0 to 3.6%R0 indicates that initial liquid hydrocarbon generation commences at a vitrinite reflectance of 0.5%R0 to 0.6%R0, and that a significant liquid hydrocarbon build‐up occurs from approximately 0.6%R0 to 0.85%R0. The start of the “oil window” corresponds to a vitrinite reflectance of 0.85%R0; however, the start of the “oil window” can vary significantly for individual coal series, and it may range up to a vitrinite reflectance of 1.15%R0. Liquid hydrocarbon generation is negligible at a vitrinite reflectance of approximately 1.8%R0, and at 2.0%R0 the hydrocarbon generative potential is exhausted. A vitrinite reflectance of 1.8%R0 corresponds to the end of the “oil window”, and for general use a vitrinite reflectance range of 0.85–1.8%R0 is suggested to define the “oil window” for humic coals and kerogen type III. The end of the “oil window” at 1.8%R0 is supported by published data, indicating a much higher thermal stability of nC15+ hydrocarbons than is generally accepted, and therefore limited oil‐to‐gas cracking at 1.3%R0. The re‐considered “oil window” between 0.85–1.8%R0 has significant implications for evaluating the prospectivity of basins dominated by terrestrial organic matter, such as coals.
HYDROCARBON GENERATION AND CHARGING IN THE OCTOBER FIELD, GULF OF SUEZ, EGYPT
Authors: El‐Ghamri M. A. , Warburton I. C. , Burley S. D.
Published: March 2006

Source rocks on‐structure in the October field are not sufficiently mature to have expelled hydrocarbons at the present day. l‐D modelling of a pseudo‐well in the deep October South Trough demonstrates that the Eocene Thebes and Senonian Sudr Formations are presently mature at depths greater than 3km. However, only the carbonate‐rich Sudr Formation has generated sufficient hydrocarbons for expulsion to take place at depths shallower than 3.5km, suggesting that reservoired oil in the October field originates predominantly from source rocks of this unit. Model results indicate that hydrocarbon expulsion from this source may have commenced as early as 20Ma in kitchen depocentres adjacent to the October field, and continued through the Pliocene.

Migration routes predicted from 2‐D modelling are complex and require downward expulsion from the Sudr Formation east and west of the October field to charge the Palaeozoic Nubian Sandstone. Mature Sudr Formation in the October South Trough first charges the Nubian and then lower Senonian Matulla Formation reservoirs in the NW compartments of the October field via flow across the NW bounding fault. The mature Sudr Formation in the Baba Trough to the SE charged the Matulla Sandstones on the eastern flanks of the October field which then back‐filled to spill into the Nubian Sandstones. Hydrocarbons generated from the Thebes Formation contribute only minor volumes to the predicted accumulations.

The presence of trap‐bounding faults and their sealing properties is shown to be a key sensitivity for charging the October field and related structures. Fault seal is required to charge known accumulations and match known hydrocarbon column heights, but extending shale smear into the Nubian Sandstone prevents the crestal October field structure from charging.

The Matulla Formation sandstones are a regional migration fairway providing charge for the Ras Budran field and Nubian Sandstone prospects to the west of the October field. Younger Mesozoic sandstones are charged by vertical migration through seals and along faults. This regional migration sequence as described for the October field is likely to Maher Ayyad of BG Egypt very kindly gave access to the seismic cross section used in the study, as well as guiding our understanding of the regional geology of the Gulf of Suez, and also provided a constructive review of the manuscript. EGPC generously provided access to well data and support for Magdi El‐Ghamri. Colin Harwood (BG Group) and Dan Carruthers and John Bunney (Permedia Research Group Inc.) commented on early drafts of the manuscript. BG Group is thanked for permission to publish.
DIAGENETIC HISTORY OF LATE PALAEOCENE POTENTIAL CARBONATE RESERVOIR ROCKS, KOPET‐DAGH BASIN, NE IRAN
Authors: Mahboubi A. , Moussavi‐Harami R. , Brenner R. L. , Gonzalez L. A.
Published: March 2006

The Upper Palaeocene (Thanetian) Chehel‐Kaman Formation in the Kopet‐Dagh Basin of NE Iran is principally composed of carbonates with minor siliciclastics and evaporites. Six stratigraphic sections were measured and more than 1,000 samples were collected for petrographic analysis, together with analyses of carbon and oxygen isotopes and trace element content. Four major carbonate lithofacies (and 13 subfacies) have been identified in previous studies and are interpretd in terms of deposition in a shallow‐marine environment.

The petrographic analyses indicate that the Chehel‐Kaman Formation carbonates have undergone a complex diagenetic history which includes compaction, cementation, micritization, dissolution, silicification, dolomitization, neomorphism and fracturing. δ18O and δ13C values in Chehel‐Kaman Formation limestones range between +0.8 and ‐15.1%0 PDB, and ‐2.82 and +3.5%0 PDB, respectively. These variations are interpreted to reflect meteoric and burial diagenetic processes. Variations in trace‐element concentrations (Fe and Mn increased while Na decreased) also indicated the effects of meteoric flushing. The limestones appear to have been formed at about 28°C.

Chehel‐Kaman Formation dolomites were divided into d1 (finely‐crystalline) and d2 (coarsely‐crystalline) types. Petrographic and geochemical results indicated that the d1 dolomites formed under sabkha conditions from a parental solution at around 26°C, while d2 dolomites formed during burial diagenesis with much hotter pore fluids (around 72°C). The paragenetic sequence indicates that primary porosity decreased during early stages of diagenesis, although secondary porosity was subsequently created improving the reservoir quality of the carbonates.