Thoracican cirripedes (Crustacea) from the Hauterivian (Lower Cretaceous) of Hannover,northern Germany     

Andy Gale 《Proceedings of the Geologists' Association. Geologists' Association》2019,130(6):659-672

Diverse thoracican cirripedes from the Hauterivian of the Hannover district of northern Germany are described, including seven species, belonging to five genera. Of these, a new genus belonging to the Scalpellidae, Jaegerscalpellum, includes one Hauterivian species, J. elegans sp. nov., an Aptian species, J. comptum (Withers, 1910) and an Albian species, J. politum (Darwin, 1851) are also referred to it. A new Cretiscalpellum, C. mutterlosei sp. nov. is described from the Hauterivian, and C. matrioni sp. nov. is described from the Middle Albian of France. The oldest record of the Unilatera Gale, 2018, Pedupycnolepas pulcher sp. nov. is described from the Hauterivian; this displays typical shell structure of the group, retained by living Verrucidae. Finally, four species of Zeugmatolepadidae, subfamily Martillepadinae, are recorded from the Hauterivian, including Martillepas hausmanni (Koch and Dunker, 1836), M. decoratus sp. nov., M. auriculum sp. nov. and Etcheslaepas borealis (Collins, 1990). The Hauterivian fauna from Hannover shows affinities both with Late Jurassic and later Cretaceous (Aptian-Cenomanian) forms, and includes the earliest scalpellids, unilateran (Pedupycnolepas) and Cretiscalpellum species known. It constrains the age of the Cretaceous cirripede evolutionary radiation to the earliest Cretaceous.  相似文献   

Single phase water flow through rock fractures   总被引：7，自引：0，他引：7  

B. Indraratna  P.G. Ranjith  W. Gale 《Geotechnical and Geological Engineering》1999,17(3-4):211-240

Flow analysis plays a major role in various geotechnical applications, and the understanding of flow mechanisms is essential for the development of a hydro-mechanical flow model suitable for underground excavations in rock. Discrete flow analysis through discontinuities is reviewed including empirical and analytical flow models. The influence of external loading on joint deformation and single-phase flow show that the surface roughness and aperture size are the prime factors influencing flow rate. Nevertheless, the idealization of natural fractures as smooth parallel plate joints is still followed in many numerical models, because of the simplicity of the cubic law when applied to fracture networks. A numerical study of water flow through a network of joints employing Universal Distinct Element Code (UDEC) is used to quantify the effects of joint orientation and external stress acting on idealized joints.It is found that, for the same joint spacing, the flow rate into an excavation depends on the boundary block size (A_b) relative to the excavation size (A_e). The inflow becomes excessive if A_b/A_e is less than 4, but becomes very small if A_b/A_e exceeds 8.  相似文献   

Integrated Rhaetian foraminiferal and conodont biostratigraphy from the Slovenian Basin, eastern Southern Alps     

Luka Gale  Tea Kolar-Jurkov?ek  Andrej ?muc  Bo?tjan Ro?i? 《Swiss Journal of Geoscience》2012,105(3):435-462

Conodonts and re-deposited shallow-water benthic foraminifera co-occur in the Upper Norian-Rhaetian Slatnik Formation of the Slovenian Basin (Southern Alps). The Mt. Kobla and Mt. Slatnik sections were investigated in order to give the first direct correlation between these two groups. The Norian-Rhaetian boundary (NRB) is placed at the First Appearance Datum of the conodont Misikella posthernsteini and is approached with the First Occurrence of the foraminifer Involutina turgida. An association of Trocholina turris with duostominids is a good marker for the Rhaetian. Careful revision of literature combined with our data culminated in reambulation of stratigraphical ranges for several foraminiferal species. The foraminiferal Triassic-Jurassic boundary (TJB) can be defined with the Last Occurrence of Galeanella tollmanni, ??Sigmoilina?? schaeferae or duostominids. The absence of the uppermost Rhaetian Misikella ultima conodont zone and the close coincidence of foraminiferal and conodont TJB could point to the presence of hiati in the upper part of the Slatnik Formation. Consequently, the exact pattern of disappearance of Late Triassic foraminifera at the boundary could not be observed. It is clear, however, that the foraminiferal assemblage was decimated for reef-dwelling foraminifera, duostominids and most of the platform-dwelling foraminifera. Biotic changes at the TJB are best explained as a result of a biocalcification crisis.  相似文献   

Comment on “Outbreak of enteroviruses and groundwater contamination in Taiwan: concept of biomedical hydrogeology” (Jean 1999) – A question of barriers and epidemiology     

P. Gale  C. Young  K. Lewin 《Hydrogeology Journal》2000,8(3):348-349

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Bulk sampling of coarse clastic sediments for particle-size analysis     

Stephen J. Gale  Peter G. Hoare 《地球表面变化过程与地形》1992,17(7):729-733

A guide is provided to the minimum sample masses required to obtain reproducible measures of the particle-size distributions of coarse sediments. This is based on studies of the actual particle-size distributions of a range of clastic deposits. Procedures are given to enable representative bulk samples of tills, fluvial gravels and beach gravels to be taken.  相似文献   

Long-term landscape evolution in Australia     

Stephen J. Gale 《地球表面变化过程与地形》1992,17(4):323-343

The main features of the Australian physical landscape are of the order of 10⁷-10⁸ years old. This contradicts the widely held view that little of the Earth's topography predates the Quaternary and that erosion cycles are carried to planation within tens of millions of years. Much of the Australian landscape must have developed over similar timescales to that of the tectonic evolution of the continent itself. The study of the geomorphology of such ancient terrains may therefore be seriously deficient unless it is considered within the context of continental-scale tectonic development. Application of this approach shows that there are strong links between the geomorphology of Australia and plate movements, ocean spreading, plate convergence, tectonostratigraphic terranes, orogenesis and epeirogenesis. The most important factor contributing to the survival of ancient landscapes in Australia is the low rate of denudation which the continent has experienced during the Mesozoic and Cenozoic. This is largely a consequence of orogenic stability, although the absence of significant Quaternary glaciation may also be of importance. However, in order for landforms to have survived over such timespans, denudation must not only have been low, but must also have been highly localized over space and time. This has been the case both on a regional scale, with long-term denudation rates of 0-2 m Ma^?1 in central Australia contrasting with higher rates along the continental margins, and on a local scale, with denudation confined to valleys, leaving divides and interfluves almost unscathed.  相似文献   

Net carbon dioxide exchange in canopies of burned and unburned tallgrass prairie     

W. J. Gale  M. B. Kirkham  E. T. Kanemasu  C. E. Owensby 《Theoretical and Applied Climatology》1990,42(4):237-244

Summary Net carbon dioxide exchange (NCE) rates were measured in a tallgrass prairie, a grassland with high productivity, to determine photosynthetic rates of the canopy. Canopy measurements were made in large, plexiglass chambers (1.21 m long; 0.91 m wide; 1.40 m tall) placed on burned and unburned areas of the prairie. The NCE rates of the canopy were compared with those of individual leaves ofAndropogon gerardii Vitman (big bluestem). In addition, CO₂ flux from the soil was quantified and compared with net photosynthetic flux. The canopy NCE rates were generally lower than those made on individual leaves. In mid-summer (11 July 1987), the maximum canopy NCE rates were 55% and 64% of those measured on individual leaves in burned and unburned treatments, respectively. Canopy NCE rates were lower than individual-leaf NCE rates for two reasons. First, the individualleaf measurements were made on young, unshaded, healthy leaves, while the canopy measurements were made on all types of leaves including senescing, shaded, and damaged leaves. Second, soil CO₂ flux into the chambers lowered NCE values. The CO₂ flux from the soil ranged from 7.2% to 28.4% of the total NCE. One needs to add soil CO₂ flux rates to the measured canopy NCE rates to obtain canopy NCE rates closer to individual-leaf NCE rates. Soil CO₂ flux decreased when conditions became dry, reaching a low of 0.06 mg CO₂m^–2s^–1, but increased after rain to 0.16 mg CO₂m^–2s^–1. Also, after rain, when plants were well watered, they were not light saturated at 1 900 µEm^–2s^–1. The NCE rates on the burned treatment were either higher or similar to those on the unburned treatment. For example, on 11 July 1987, NCE rates were higher on the burned treatment (0.66 mg CO₂m^–2s^–1) compared to the unburned treatment (0.47 mg CO₂m^–2s^–1). During the rest of July and August, the rates of the two treatments were not significantly different. But in September and October, the NCE rates were again higher on the burned treatment compared to the unburned treatment. The results indicated that canopy NCE rates may be more indicative of the productivity of the prairie than individual-leaf measurements made only on young, highly productive leaves.Contribution No. 89-82-J from the Kansas Agricultural Experiment Station. This research was supported, in part, by Grant No. DE-FG02-84ER60253.A000.With 4 Figures  相似文献   

The thoracican cirripede genus Concinnalepas Gale, 2014 (Crustacea) from the Middle and Upper Jurassic of southern England and northern France     

Andy S. Gale 《Proceedings of the Geologists' Association. Geologists' Association》2021,132(3):332-345

New material of the cirripede genus Concinnalepas is described from the Kimmeridge Clay (Tithonian) of Dorset (UK) and the Marnes de Port (Bathonian) of Port-en-Bessin in Normandy (France). Articulated specimens of C. costata (Withers, 1928), attached to driftwood from Kimmeridge, provide hitherto unknown details of tiered lateral plate formation in the species, and Concinnalepas bessinensis sp. nov. and C. rugosa sp. nov. are described from Normandy and Dorset, respectively. Concinnalepas bessinensis sp. nov. is the oldest calcite-shelled cirripede known to date. A review of the distribution of Jurassic calcareous cirripedes demonstrates that pre-Kimmeridgian records are very sparse and scattered and the early evolutionary history of the group is poorly known. The late Kimmeridgian and Tithonian saw a radiation of the Family Zeugmatolepadidae and a great increase in abundance of cirripedes that mostly lived as epiplankton, attached to driftwood and ammonite shells.  相似文献   

Uranium and thorium abundances in Indian kimberlites     

D.K. Paul  N.H. Gale  P.G. Harris 《Geochimica et cosmochimica acta》1977,41(2):335-339

Abundances of U and Th have been determined in 21 kimberlites from India by delayed fission neutron technique. Whole-rock U ranges from 1.87 to 3.93 ppm but Th shows wider variation from 14.02 to 60.44 ppm. Average Th/U ratios in three main diatremes are 7.9, 8.8 and 10.0. The interrelationships between U, Th and K are variable and complex. A positive correlation exists between P₂O₅ and U and Th. Model calculations suggest that enrichment of U involved considerable mantle reaction during ascent.  相似文献   

Vertical transport of steroid alcohols and ketones measured in a sediment trap experiment in the equatorial Atlantic Ocean     

Robert B. Gagosian  Steven O. Smith  Gale E. Nigrelli 《Geochimica et cosmochimica acta》1982,46(7):1163-1172

The vertical flux and free steroid alcohol (sterol) and ketone composition of particulate material was determined using sediment traps deployed at 389, 988, 3755 and 5068 m at a station in the equatorial North Atlantic, PARFLUX E. Cholest-5-en-3β-ol (cholesterol) was found to be the dominant sterol in all the traps. This compound had a maximum flux at 988 m, accounting for more than 90% of the sterols at this depth. Inputs from mesopelagic Zooplankton populations living in or migrating to depths between the 389 and 988 m traps appear to be responsible for this distribution. The deeper two traps exhibited an increased flux of phytosterols relative to cholesterol, probably due to (a) the incorporation of labile phytoplankton remains in fecal pellets and rapid transport into the deep sea and (b) differential dissolution of heterogeneous large particles. A maximum of 5–22% of the sterols produced in the euphotic zone were present in the 389 m trap. This value drops to less than 1% for the 5068 m trap, 200 m above the sediment surface.In general steroid ketone fluxes gradually decreased with depth. Δ4-Stenones were found in greater abundance than their saturated counterparts. Cholest-4-en-3-one was the major steroid ketone detected in all the traps. A five-fold increase with depth in the cholest-4-en-3-one to cholesterol ratio is most likely due to microbial oxidation of sterols to steroid ketones, or higher Δ4-stenone inputs relative to sterols from organisms.  相似文献