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1.
Rosamond L. Naylor Walter P. Falcon Daniel Rochberg Nikolas Wada 《Climatic change》2001,50(3):255-265
Despite the strong signal of El Niño/Southern Oscillation (ENSO) events on climate in the Indo-Pacific region, models linking ENSO-based climate variability to seasonal rice production and food security in the region have not been well developed or widely used in a policy context. This study successfully measures the connections among sea surface temperature anomalies (SSTAs), rainfall, and rice production in Indonesia during the past three decades. Regression results show particularly strong connections on Java, where 55% of the country's rice is grown. Two-thirds of the interannual variance in rice plantings and 40% of the interannual variance in rice production during the main (wet) season on Java are explained by year-to-year fluctuations in SSTAs measured 4 and 8 months in advance, respectively. These effects are cumulative; during strong El Niño years, production shortfalls in the wet season are not made up later in the crop year. The analysis demonstrates that quantitative predictions of ENSO's effects on rice harvests can provide an additional tool for managing food security in one of the world's most populous and important rice-producing countries. 相似文献
2.
The postcumulus evolution of a portion of the Bushveld Complex that includes the Merensky reef is inferred from the study
of a continuous 56 m drill core. The core penetrated the basal orthopyroxenites of the Merensky and Bastard units, the massive
anorthosites overlying the two pyroxenites and about 10 m of norite underlying the Merensky pyroxenite. Detailed profiles
of major, minor and rare earth element (REE) contents of clinopyroxene and orthopyroxene were determined by electron and ion
probe. Good correlations exist between textural and lithological variations and the REE contents of the pyroxenes. Specifically,
enrichments in pyroxene REE abundances are observed in the basal pyroxenites of the Merensky and Bastard units relative to
the underlying and overlying rocks. In the pyroxenites the Nd content of clinopyroxene is typically over 12 ppm and reaches
nearly 40 ppm (≈90 × chondrite), and Nd/Yb ratio is in the range 8 to 25. These extreme enrichments in REE are not accompanied
by large variations in major element contents. Computations of the compaction parameters relevant to the conditions of crystallization
of the Bushveld Complex combined with a consideration of cooling history confirm the importance of compaction as a post-cumulus
process. This analysis indicates that the geochemical variability is a result of redistribution of interstitial melt driven
by compaction and cannot reflect variations in the initial porosity of the accumulating crystal pile. A model for the development
of the Atok section is developed. The Merensky anorthosite is interpreted to have served as a barrier to the upward porous
flow of late-stage, hydrous and incompatible-element enriched melt, which was thus trapped in the underlying Merensky pyroxenite.
The flow was driven by compaction of the 350+ meter-thick section of predominantly norite beneath the anorthosite. The introduction
and accumulation of this melt in the pyroxenite and subsequent cooling resulted in partial dissolution, recrystallization
and REE enrichment of the rock forming minerals, and in the formation of the main lithologic features of the Merensky pyroxenite.
Further upward percolation of the interstitial melt through the Merensky anorthosite was restricted to channels due to the
relatively impermeable nature of the cemented anorthosite. This melt accumulated in and metasomatized the Bastard pyroxenite
in the same manner as the Merensky pyroxenite, having again been trapped by the overlying Bastard anorthosite.
Received: 10 July 1996 / Accepted: 27 February 1997 相似文献
3.
Jason K Blackburn rew Curtis Frances Currin Mujica Farrell Jones Patricia Dorn Rosamond Coates 《Transactions in GIS》2008,12(2):249-265
This article describes a web‐based data entry and GIS‐driven mapping system designed for an ethnographic and entomological survey of Chagas’ disease, an emerging zoonotic disease, and Triatoma dimidiata, a primary vector, in the Los Tuxtlas region of Veracruz, Mexico. To better understand this disease in the region, a collaborative, multi‐disciplinary study was initiated to conduct a spatial investigation of T. dimidiata and a community‐by‐community survey of local perceptions of the disease. In order to facilitate such a collaborative effort the CODES‐GIS was developed. This system allows for (near) real‐time mapping, analyses, disease reporting, and results sharing. CODES‐GIS provides a framework for a research team working in a remote area with limited technology, software, or GIS expertise to benefit from (near) real‐time spatial analyses performed at collaborating institutions. The system is bi‐directional, where field personnel can upload data to the system for field‐based map production. Likewise, laboratory personnel can upload diagnostics data for viewing by field personnel. In this way, the system provides a virtual link between the field and the laboratory to increase the speed at which results are returned to the local community. The CODES‐GIS is described along with a selection of study results. 相似文献
4.
The determination of the void ratio and stress state distribution in undisturbed soil is still an ambitious aim which cannot be reached by sampling from bore holes. Therefore, an alternative method is proposed to determine soil density and stress state using dispersion wave measurements and cone penetration tests. Dispersion wave measurements and resonant-column tests are carried out to measure the shear wave velocity and shear modulus distribution with depth. Using finite element calculations a relationship between cone penetration resistance, stress state and void ratio is derived. From these results the void ratio distribution and the stress state can be calculated inversely. The inverse method is applied to real test data. The results of the inverse parameter determination are shown and assessed regarding the possibilities and the limitations of the presented method. 相似文献
5.
DENG Xiangzheng HUANG Jikun QIAO Fangbin Rosamond L. Naylor Walter P. Falcon Marshall Burke Scott Rozelle David Battisti 《地理学报》2010,20(1):3-16
This paper aims to demonstrate the relationships between ENSO and rice production of Jiangxi province in order to identify the reason that ENSO might have little effect on Chinese rice production. Using a data set with measures of Jiangxi’s climate and rice production, we find the reason that during 1985 and 2004 ENSO’s well correlated with rainfall did not promote Chinese rice production. First, the largest effects of ENSO mostly occur in the months when there is no rice in the field. Second, there is almost no temperature effect. Finally, the monthly distribution of rainfall is almost the same in ENSO and neutral years because the largest effects are during months when there is the least rain. In addition, due to the high irrigation share and reliable and effective irrigation facilities of cultivated land, China’s rice production is less climate-sensitive. 相似文献
6.
Coupled CaAl-NaSi diffusion in plagioclase feldspar: Experiments and applications to cooling rate speedometry 总被引：5，自引：0，他引：5
Timothy L Grove Michael B Baker Rosamond J Kinzler 《Geochimica et cosmochimica acta》1984,48(10):2113-2121
The rate of CaAl-NaSi interdiffusion in plagioclase feldspar was determined under 1 atm anhydrous conditions over the temperature range 1400° to 1000°C in calcic plagioclase (An80?81) by homogenizing coherent exsolution lamellae. The dependence of the average interdiffusion coefficient on temperature is given by the expression: in °K). This value is for diffusion perpendicular to the (03 1?) interface of the lamellae. CaAl-NaSi interdiffusion is 4 to 5 orders of magnitude slower than oxygen diffusion in the temperature range 1400° to 1200°C and possibly 10 orders of magnitude slower at subsolidus temperatures.The large differences in diffusion rates explain the apparent contradiction posed by the plagioclases of large layered intrusions (e.g., the Skaergaard), which retain delicate Ca, Na compositional zoning profiles on the micron scale, but have undergone complete oxygen isotopic exchange with heated meteoric groundwater from the surrounding wall rocks. CaAl-NaSi diffusion is slow, the closure temperature is high (within the solidus-liquidus interval), and Ca-Na zoning is preserved. Oxygen diffusion is faster, the closure temperature is lower (350°-400°C) and the feldspars exchange oxygen with the low-temperature hydrothermal fluids.The complex micron-scale oscillatory zones in plagioclase can also be used as cooling rate speedometers for volcanic and plutonic plagioclase. Cooling histories typical of large mafic intrusions (e.g. the Stillwater) are slow, begin at high initial temperatures (1200°C) and result in homogenization of oscillatory zones on the scale of 10 microns. The oscillatory zones found in the plagioclase of granodioritic plutons are preserved because cooling is initiated at a lower temperature (1000°C) limiting diffusion to submicron length scales despite the slow cooling rate of the intrusion. 相似文献
7.
Huai-Jen Yang Rosamond J. Kinzler T. L. Grove 《Contributions to Mineralogy and Petrology》1996,124(1):1-18
A new method for modeling fractional crystallization processes that involve olivine (ol), plagioclase (plag) and augite (aug)
is presented. This crystallization assemblage is the major control on the chemical variations in mid-ocean ridge basalts.
The compositional and temperature variations in ol-plag-aug saturated basalts over a range of pressures are described using
empirical expressions. A data base of 190 experiments in natural and basalt-analog chemical systems is used to describe temperature,
Al, Ca and Mg molar fractions as functions of Si, Fe, Na, Ti and K molar fractions and pressure. Increases in the abundances
of Na and K cause Ca and Mg abundances to decrease and Al abundance to increase in ol-plag-aug saturated melts. The equations
can be used to predict pressure and temperature and thus provide a useful thermobarometer. A model is described to calculate
ol-plag-aug fractional crystallization as a function of pressure and melt composition, using melt and augite models developed
here, combined with existing models for olivine-melt and plagioclase-melt equilibria. We compare the fractional crystallization
sequence of ALV-2004-3-1 predicted from the models presented in this paper, Langmuir et al. (1992) modified by Reynolds (1995),
Ghiorso and Sack (1995) and Ariskin et al. (1993) at 0.001 and 4 kbar. As an example the model is applied to estimate pressure
of crystallization of glasses from the east flank of the East Pacific Rise at 11°45′N.
Received: 24 July 1995 / Accepted: 12 January 1996 相似文献
8.
T. L. Grove R. J. Kinzler M. B. Baker J. M. Donnelly-Nolan C. E. Lesher 《Contributions to Mineralogy and Petrology》1988,99(3):320-343
At Medicine Lake volcano, California, andesite of the Holocene Burnt Lava flow has been produced by fractional crystallization of parental high alumina basalt (HAB) accompanied by assimilation of granitic crustal material. Burnt Lava contains inclusions of quenched HAB liquid, a potential parent magma of the andesite, highly melted granitic crustal xenoliths, and xenocryst assemblages which provide a record of the fractional crystallization and crustal assimilation process. Samples of granitic crustal material occur as xenoliths in other Holocene and Pleistocene lavas, and these xenoliths are used to constrain geochemical models of the assimilation process.A large amount of assimilation accompanied fractional crystallization to produce the contaminated Burnt lava andesites. Models which assume that assimilation and fractionation occurred simultaneously estimate the ratio of assimilation to fractional crystallization (R) to be >1 and best fits to all geochemical data are at an R value of 1.35 at F=0.68. Petrologic evidence, however, indicates that the assimilation process did not involve continuous addition of granitic crust as fractionation occurred. Instead, heat and mass transfer were separated in space and time. During the assimilation process, HAB magma underwent large amounts of fractional crystallization which was not accompanied by significant amounts of assimilation. This fractionation process supplied heat to melt granitic crust. The models proposed to explain the contamination process involve fractionation, replenishment by parental HAB, and mixing of evolved and parental magmas with melted granitic crust. 相似文献
9.
This paper aims to demonstrate the relationships between ENSO and rice production of Jiangxi province in order to identify the reason that ENSO might have little effect on Chinese rice production. Using a data set with measures of Jiangxi's climate and rice production,we find the reason that during 1985 and 2004 ENSO's well correlated with rainfall did not promote Chinese rice production. First,the largest effects of ENSO mostly occur in the months when there is no rice in the field. Second,there is almost ... 相似文献
10.
High pressure phase relations of primitive high-alumina basalts from Medicine Lake volcano,northern California 总被引：8，自引：1，他引：8
Karen S. Bartels Rosamond J. Kinzler Timothy L. Grove 《Contributions to Mineralogy and Petrology》1991,108(3):253-270
Anhydrous phase relations were determined at 1 atm and 10 to 15 kbar for primitive high-alumina basalts (79–35g and 82–72f)
from Giant Crater at Medicine Lake volcano. These compositions are multiply saturated with olivine+augite+plagioclase+spinel+/-orthopyroxene
near the liquidus at about 11 kbar. Experiments on mixtures of sample 79–35g with orthopyroxene and olivine determined the
location of the multiple saturation boundaries where liquid coexists with the assemblage olivine+augite+orthopyroxene+plagioclase
at 10 kbar and olivine+augite+orthopyroxene+spinel at 15 kbar. The mix experiments showed that primitive Medicine Lake high
alumina basalts (HABs) are close in composition to liquids in equilibrium with a mantle lherzolite source containing olivine+augite+
orthopyroxene+spinel+plagioclase at 11 kbar. Orthopyroxene observed as a near liquidus phase in an 11 kbar experiment on sample
82–72f supports this conclusion. The most primitive HABs from Medicine Lake are low in K2O (0.07 wt.%), high in MgO (>10 wt.%) and Ni (231 ppm), and have light-rare earth element depletions and large ion lithophile
element enrichments. A model for the origin of these near-primary high-alumina basalts is that they are partial melts of a
MORB-like mantle lherzolite source that has been enriched by a fluid component derived from the subducted slab. The HAB magma
segregated from its mantle residue just below the base of the crust near the crust-mantle boundary. 相似文献