Synneusis of Kilauea Iki olivines   总被引：1，自引：1，他引：0  

Kathleen R. Schwindinger  Alfred T. Anderson Jr 《Contributions to Mineralogy and Petrology》1989,103(2):187-198

Olivine phenocrysts in the picritic scoria that erupted from Kilauea Iki in 1959 occur as glomeroporphyritic aggregates of 2–16 crystals. The compositions and three-dimensional textures of the olivines vary within an aggregate and within individual lapilli. The attachment of crystals from different environments indicates that these aggregates formed by synneusis — the swimming together of crystals. Most of the crystals are attached along faces with their a crystallographic axes parallel and their c axes either parallel or perpendicular, so that the structural mismatch and interfacial energy are minimized. Observed facial attachments are consistent with fluid dynamical interactions of crystals falling with their large {010} faces horizontal. The aggregates formed in a liquid-rich magma. Rough computations suggest that the minimum aggregation time could be on the order of minutes. Aggregation of very small crystals suggests that the yield strength was less than 3 dynes cm^–2. The textures of the aggregates are similar to those of cumulate peridotites.  相似文献   

The effect of tidally induced changes in the creekbank water table on pore water chemistry     

Kathleen Agosta 《Estuarine, Coastal and Shelf Science》1985,21(3):389-400

Water moved into the creekbank sediments in direct response to the changing levels of the water table caused by the tides. The net water loss of the sediments was 3–30% on each low tide and this loss was confined to within 4 m (horizontal) of the creek. The replacement of this water by incoming tidal water could not supply sufficient nutrients for the growth of creekbank Spartina. However, during ebb tide there was a replacement of water in the creekbanks with nutrient-rich water from the marsh interior as demonstrated by the large changes in pore water chemistry over a tidal cycle. The concentration and the range of a chemical parameter depended upon the stage of the tide, the tidal range, the time of year and (for salinity) the rainfall patterns of the month preceding sampling. Over a single tidal cycle the maximum ranges were: salinity ‰, 26–33; alkalinity, 2·5–13·6 med 1^?1, ammonia, 2–400 μm, sulfate, 23·5–29 mmol 1^?1. Measurable concentrations of sulfide were only found in a few samples. This high nutrient water can supply nitrogen and probably other nutrients to Spartina.  相似文献   

Realizing the potential of British grasslands: some problems and possibilities     

Alec Lazenby  Kathleen M. Down 《Applied geography (Sevenoaks, England)》1982,2(3):171-188

Grass is easily the most important crop in Britain and an analysis is made of the factors affecting its yield and quality. There follows some mention of grass utilization, and of the concept of Metabolizable Energy which enables feed value of forage to be related to nutrient requirements of ruminant animals. Grassland output could be doubled if known technology on herbage production and utilization were implemented nationwide, and an analysis is included of why the crop is presently so under-used. Prospects for milk and meat production are assessed and the importance of improving grassland management stressed, both to maintain the farmer's living standards and to increase market competitiveness. Major research objectives are highlighted and the need for close contact between the researcher, adviser and farmer emphasized to achieve full exploitation of grassland at least cost.  相似文献   

Textures in Partially Solidified Crystalline Nodules: a Window into the Pore Structure of Slowly Cooled Mafic Intrusions   总被引：2，自引：0，他引：2  

Holness  Marian B.; Anderson  Alfred T.; Martin  Victoria M.; Maclennan  John; Passmore  Emma; Schwindinger  Kathleen 《Journal of Petrology》2007,48(7):1243-1264

Abundant glass is present along grain boundaries in coarse-grained,glass-bearing, crystalline gabbroic and peridotitic nodulesentrained and erupted in lavas from Iceland, Santorini and MaunaLoa (Hawaii), even when the total porosity is less than a fewvolume per cent. The glass films vary from a few microns toa few tens of microns thick, and are associated with stringsof small lensoid grain boundary pockets formed by impingementduring crystal growth. Additional porosity occurs as extensiveliquid-filled pockets adjacent to included grains within oikocrystsand as large triangular pockets formed by impingement of planar-sidedgrains. Interstitial material within glass films, and the irregularityof film thickness along a single grain boundary, suggest thatthe present pore structure is representative of the pore structurebefore entrainment and eruption. Pore geometry is consistentwith a dominant control by crystal growth during solidification,with little or no evidence for control by minimization of internalenergies driven by textural equilibration. Similarities betweenliquid distribution in the crystalline nodules and that of late-stage,interstitial phases in fully solidified mafic cumulates fromthe Rum and Skaergaard intrusions demonstrate that the crystallinenodules provide information about the latest stages of solidificationin slowly cooled mafic plutons. The highly permeable networkof intersecting liquid films, lenses and pockets may promotein situ crystallization in the solidifying mush, explainingthe common presence of adcumulates in such intrusions. KEY WORDS: textures; liquid distribution; mafic cumulates; crystalline nodules  相似文献   

Seismic reflection studies of the Amery Ice Shelf, East Antarctica: delineating meteoric and marine ice     

Kathleen L. McMahon  Mark A. Lackie 《Geophysical Journal International》2006,166(2):757-766

  相似文献   

Genesis of marine terrace soils,Barbados, West Indies: Evidence from mineralogy and geochemistry     

Daniel R. Muhs  Russell C. Crittenden  John N. Rosholt  Charles A. Bush  Kathleen C. Stewart 《地球表面变化过程与地形》1987,12(6):605-618

Well-developed, clay-rich soils dominated by interstratified kaolinite-smectite are found on the uplifted coral reef terraces on the island of Barbados. The reef limestone is unlikely to have been the soil parent material however, because it is 98 per cent CaCO₃ and geomorphic evidence argues against the 20 m of reef solution required to produce the soils by this process. The mineralogy of the sand, silt, and clay fractions of the soils, and trace element geochemistry, suggest that aeolian materials carried on the trade winds from Africa, volcanic ash from the island of St. Vincent, and quartz from Tertiary bedrock on the island itself are the parent materials for the soils.  相似文献   

Variation in pyrite size, form, and microlithotype association in the springfield (no. 9) and herrin (no. 11) coals, Western Kentucky     

Kathleen Adams Frankie  James C. Hower 《International Journal of Coal Geology》1987,7(4)

Channel samples of the Springfield (No. 9) and Herrin (No. 11) (Pennsylvanian, Desmoinesian/Westphalian D) coals were acquired in three mines each in the Western Kentucky coal field. Pyrite was characterized petrographically in terms of its size, form, and microlithotype association. Within each coal seam significant variations in the amount of pyrite of certain forms occurred between the sites. Pyritic sulfur as determined chemically did not exhibit significant variation between the seams or between the sites. The variation in dendritic pyrite in vitrite plus clarite between seams and between sites was highly significant and the variation in framboidal pyrite in vitrite plus clarite between sites was also highly significant.  相似文献   

Cyclic and event stratification: G. Einsele and A. Seilacher (Editors). Springer,Berlin, 1982, xiv + 540 pp., DM 60.00/approx. US $ 28.00 (paperback)     

Edwin D. McKee 《Sedimentary Geology》1983,35(3):228-230

  相似文献   

Detection of an Impermeable Boundary in an Anisotropic Formation: A Case Study     

S. C. Way  C. R. McKee 《Ground water》1984,22(5):579-583

Direct mirror-well image theory to locate an impermeable boundary does not apply in anisotropic formations because the relationship between flow lines and equipotential lines is distorted due to directional transmissivity. A simple approach enables an impermeable boundary to be located in anisotropic formations, and it can be verified with a field example.  相似文献   

Origins and effects of coagulation in lakes     

Prof. Dr. Charles R. O'Melia  Ms. Kathleen S. Bowman 《Aquatic Sciences - Research Across Boundaries》1984,46(1):64-85

A physical model for the transport and deposition of particles in lakes is formulated mathematically, solved numerically, compared with some field results available in the literature, and used to simulate the effects of coagulation and sedimentation in some limnetic systems. The results indicate that these processes exert significant and perhaps controlling effects on the transport and fate of particles and associated pollutants and nutrients in lakes.  相似文献