The California Electric Power Crisis: Lessons for Other States     

Barry D. Solomon  Michael K. Heiman 《The Professional geographer》2001,53(4):463-468

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Internal constitution and evolution of the moon     

Sean C. Solomon  M. Nafi Toksöz 《Physics of the Earth and Planetary Interiors》1973,7(1):15-38

The composition, structure and evolution of the moon's interior are narrowly constrained by a large assortment of physical and chemical data. Models of the thermal evolution of the moon that fit the chronology of igneous activity on the lunar surface, the stress history of the lunar lithosphere implied by the presence of mascons, and the surface concentrations of radioactive elements, involve extensive differentiation early in lunar history. This differentiation may be the result of rapid accretion and large-scale melting or of primary chemical layering during accretion; differences in present-day temperatures for these two possibilities are significant only in the inner 1000 km of the moon and may not be resolvable. If the Apollo 15 heat-flow result is representative of the moon, the average uranium concentration in the moon is 0.05–0.08 p.p.m.Density models for the moon, including the effects of temperature and pressure, can be made to satisfy the mass and moment of inertia of the moon and the presence of a low-density crust inferred from seismic refraction studies only if the lunar mantle is chemically or mineralogically inhomogeneous. The upper mantle must exceed the density of the lower mantle at similar conditions by at least 5%. The average mantle density is that of a pyroxenite or olivine pyroxenite, though the density of the upper mantle may exceed 3.5 g/cm³. The density of the lower mantle is less than that of the combined crust and upper mantle at similar temperature and pressure, thus reinforcing arguments for early moon-wide differentiation of both major and minor elements. The suggested density inversion is gravitationally unstable and implies stresses in the mantle 2–5 times those associated with the lunar gravitational field, a difficulty that can be explained or avoided by: (1) adopting lower values for the moment of inertia and/or crustal thickness, or (2) postulating that the strength of the lower mantle increases with depth or with time, either of which is possible for certain combinations of composition and thermal evolution.A small iron-rich core in the moon cannot be excluded by the moon's mass and moment of inertia. If such a core were molten at the time lunar surface rocks acquired remanent magnetization, then thermal-history models with initially cold interiors strongly depleted in radioactive heat sources as a primary accretional feature must be excluded. Further, the presence of ～||pre|40 K in a FeFeS core could significantly alter the thermal evolution and estimated present-day temperatures of the deep lunar interior.  相似文献   

Heavy metal accumulation in estuarine sediments in a historical mining of Cornwall     

W.W.-S. Yim 《Marine pollution bulletin》1976,7(8):147-150

Sediments in the Hayle estuary in a historical mining area of Cornwall have been found to contain exceptionally high concentrations of tin, arsenic, copper, lead, tungsten and zinc. In this study, the distribution of these heavy metals is correlated with pollution from past mining activity through mine waste discharge into streams, and changes which took place at the time of the development of the Upton Towans.  相似文献   

Variations in the velocities of the major plates since the late cretaceous     

Daniel M. Davis  Sean C. Solomon 《Tectonophysics》1981,74(1-2)

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The genesis of sediment-hosted,exhalative zinc + lead deposits   总被引：2，自引：0，他引：2  

M. J. Russell  M. Solomon  J. L. Walshe 《Mineralium Deposita》1981,16(1):113-127

Large sediment-hosted lead+zinc deposits like Mount Isa, McArthur River, Navan, Rammelsberg and Sullivan form a distinctive group characterised by stratiform, syngenetic sulphide ores that formed in local basins on the sea floor as a result of protracted hydrothermal activity accompanying continental rifting. Generally there is a development of a sedimentary pre-ore phase mineralization often featuring manganese followed by zinc±lead, iron and chert. Lower main phase zinc+lead lenses are usually almost devoid of copper but Cu tenors increase toward the middle or top of the ore sequences. Hanging wall trace element haloes are common. These characteristics are accounted for by deriving the ore solutions from subsurface convective circulation of modified highly saline seawater. The circulation is initiated during rifting and driven by a high geothermal gradient. As a result of continued extensional strain and cooling of the rock column the brittle-to-ductile transition zone is depressed and the circulation penetrates to greater depth with time. Of the ore metals the downward-penetrating convection fluids first leach and transport zinc and lead, but with increasing temperature are later able to leach and transport some copper. Unless convective circulation ceases the metal sequence generally reverses as the cooling phase sets in. The minimum distance separating major coeval orebodies of this type is 18 km which is a function of the size of the convective systems.  相似文献   

Silurian Sedimentation in the South Qilian Belt: Arc-Continent Collision-related Deposition in the NE Tibet Plateau?     

YAN Zhen  FU Changlei  Jonathan C. AITCHISON  ZHOU Renjie  Solomon BUCKMAN  CHEN Lei 《《地质学报》英文版》2020,94(4):901-913

The South Qilian belt mainly comprises an early Paleozoic arc-ophiolite complex, accretionary prism, microcontinental block, and foreland basin. These elements represent accretion-collision during Cambrian to Silurian time in response to closure of the Proto-Tethyan Ocean in the NE of the present-day Tibet Plateau. Closure of the Proto-Tethyan Ocean between the Central Qilian block and the Oulongbuluke block and the associated collision took place from NE to SW in a zipper-like style. Sediment would have been dispersed longitudinally SW-ward with a progressive facies migration from marginal alluvial sediments toward slope deep-water and deep-sea turbidites. This migration path indicates an ocean basin that shrank toward the SW. The Balonggongga'er Formation in the western South Qilian belt represents the fill of a latest Ordovician-Silurian remnant ocean basin that separated the Oulongbuluke block from the Central Qilian block, and records Silurian closure of the Proto-Tethyan Ocean and subduction beneath the Central Qilian block. However, alluvial deposits in the Lajishan area were accumulated in a retro-foreland basin, indicating that continent-continent collision in the eastern South Qilian belt occurred at c. 450–440 Ma. These results demonstrate that the Proto-Tethyan Ocean closed diachronously during early Paleozoic time.  相似文献   

An ML scale for Eastern Dharwar Craton and adjoining regions     

Sharma  Aman  Vashisth  Divakar  Naresh  B.  Suresh  G.  Raju  P. Solomon  Raghavan  R. Vijaya  Srinagesh  D. 《Journal of Seismology》2021,25(5):1251-1263

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Zn–Pb–Cu volcanic-hosted massive sulphide deposits: criteria for distinguishing brine pool-type from black smoker-type sulphide deposition     

M. Solomon  F. Tornos  R. R. Large  J. N. P. Badham  R. A. Both  Khin Zaw 《Ore Geology Reviews》2004,25(3-4):259-283

Eight Zn–Pb–Cu massive sulphide deposits that appear to have formed on the sea floor (seven in Spain, one in Tasmania) are believed to have been precipitated in brine pools, based on the salinities and temperatures of fluid inclusions in underlying stockworks. Comparing the geological features of these deposits with those of the Zn–Pb–Cu massive sulphide ores of the Hokuroku Basin, Japan, which have formed as mounds from buoyant fluids of low salinity, shows that brine pool deposits have: (1) potentially very large size and tonnage, and high aspect ratio, (2) higher Zn/Cu and Fe/Cu values, (3) no evidence of chimneys, (4) relatively abundant framboidal pyrite and primary mineral banding, (5) reduced mineral assemblages (pyrite-arsenopyrite/pyrrhotite), and minor or rare barite in the massive sulphide, (6) associated stratiform and/or vein carbonates, (7) relatively unimportant zone refining, (8) lack of vertical variation in sphalerite and sulphur isotopic compositions, and (9) evidence of local bacterial sulphate reduction. Application of these criteria to the Rosebery deposit in Tasmania, for which there are no fluid inclusion data, leads to the conclusion that the southern section was deposited as separate lenses in a brine-filled basin or basins. Other potential candidates include Brunswick no. 12 and Heath Steele (Canada), Woodlawn and Captains Flat (New South Wales), Hercules and Que River (Tasmania), and Tharsis and the orebodies at Aljustrel (Spain and Portugal). Recently published fluid inclusion data for Gacun (China) and Mount Chalmers (Queensland) suggest that not all ores deposited from highly saline fluids have reduced mineral assemblages.  相似文献   

Micromycetes from the Saline Arubotaim Cave: Mount Sedom, The Dead Sea Southwestern Shore, Israel     

Isabella Grishkan  Eviatar Nevo  Solomon P. Wasser 《Journal of Arid Environments》2004,57(4):431

We examined the soil microfungal community of the saline Arubotaim Cave, Israel. A total of 68 species from 28 genera were isolated. The most prominent features of the cave mycobiota were: the prevailing number of melanin-containing micromycetes; the abundant presence of the Aspergillus species; a comparatively large share of sexual ascomycetes; and the spatial and temporal variation of the mycobiota composition. Nine species were considered as a characteristic micromycete core for the cave. Many of the micromycetes isolated are distributed worldwide. This confirms the conclusion of many mycologists working in areas with saline and arid soils that there is no specific halophilous mycobiota characteristic for these soils.  相似文献   

香港西博寮海峡WB7孔的第四纪沉积及硅藻研究   总被引：1，自引：1，他引：1  

李家英  严维枢 《地质论评》1997,43(6):616-630

香港西搏寮海峡ＷＢ７孔第四纪沉积物中共有硅藻５４属，１８６个分类单位，该硅藻生物群以沿岸潮间带和近岸浅海种为主，伴有热性，暖热性浮游硅藻。依据硅藻在剖面中的分布特征，丰度及百分比含量变化，自下而上可划分出６个硅藻组合带。并明显反映该沉积时期的古气候与古环境特征，其中第５，６，带相当于全新世，其余４个带均属更新世。  相似文献