Occurrence and distribution of sulfur in peat-forming environments of southern Florida     

Arthur D. Cohen  William Spackman  Philip Dolsen 《International Journal of Coal Geology》1984,4(1):73-96

Cores and surface samples of peats from the Everglades—Mangrove region of Southern Florida were analyzed for total sulfur and pyritic sulfur. These values were compared with the petrographic-botanical components of the peats as determined from point-counts of oriented microtome sections. Pyrite occurs as individual euhedral crystals, loosely packed framboids, and lenses or crusts of minute crystals. Framboids and minute crystals are often associated with organic matter and sometimes with bacteria and fungi. Pyrite tends to selectively occur in void spaces in or between peat tissues. In samples containing very small amounts of pyrite, framboidal pyrite is the prevalent form.Marine to brackish peats contain the highest pyrite and total sulfur contents, with brackish peats generally containing more pyrite than marine peats. Pyrite tends to be lower in all peats within 30 cm of the surface, whether marine or brackish.Burial of freshwater peats beneath marine or brackish peats tends to increase the total sulfur and pyritic sulfur in the underlying peats. Burial beneath brackish-water, clay-rich deposits (such as splays) tends to increase total sulfur and pyritic sulfur in the underlying deposits more than burial beneath less clay-rich deposits.  相似文献   

Creep parameters of rocks on an engineering scale     

Han-Ping Chin  J. David Rogers 《Rock Mechanics and Rock Engineering》1987,20(2):137-146

Vertical shafts of 137 cm diameter were excavated to measure creep deformations of carbonate shale, weathered limestone and tuff. Changes of diameter at successive time intervals were recorded under constant, radial pressure. Three typical models were chosen for a regression analysis of the experimental data and their fitness were compared to one another in a statistical approach.The introduction of a steady state flow term improves the data fit considerably, and the power law was found to yield an even better result. It was also determined that rock masses in the field contain numerous discontinuities which increase the plasticity of the three types of rock tested. The viscosities determined in-situ were found to be much lower than those derived from small intact specimens by up to several orders of magnitude.  相似文献   

Local member response in offshore structures under earthquake excitations     

Stavros A. Anagnostopoulos  Arthur R. Culbertson 《地震工程与结构动力学》1982,10(3):349-358

It is pointed out that local vibrations of certain members in earthquake excited offshore structures can induce substantial stresses that may often dominate the design of these members. Such vibrations are not accounted for in dynamic analyses of structural models with masses lumped at the joints. A practical, easy to implement solution to this problem is recommended and results from an actual structure, subjected to a three-component real earthquake, are presented demonstrating the importance of local inertia effects.  相似文献   

Handbook of exploration geochemistry. volume 1: analytical methods in geochemical prospecting: W. K. Fletcher,Elsevier, 1981, 256 pp, $59.50     

Arthur W. Rose 《Geochimica et cosmochimica acta》1982,46(5):834-835

  相似文献   

ORGANIC COMPOUNDS AND GROUND-WATER POLLUTION     

Wayne A. Pettyjohn  Arthur W. Hounslow 《Ground Water Monitoring & Remediation》1983,3(4):41-47

  相似文献   

DDT,PCB and benzo(a)pyrene levels in white croaker (Genyonemus lineatus) from southern California     

Richard W Gossett  Harold W Puffer  Robert H Arthur  David R Young 《Marine pollution bulletin》1983,14(2):60-65

In 1978 the California Department of Fish and Game carried out a major, independent sportfishing survey in southern California. The results of that survey indicated that approximately one million angler-trip hours per year were spent fishing and that one in three fish caught was a white croaker (Genyonemus lineatus). There was no attempt by the Department of Fish and Game to determine the disposition of caught fish. We conducted a subsequent survey in 1980 which included 12 popular sportfishing sites in the Los Angeles area. Our results also indicated that one in three fish caught was a white croaker. In addition our survey showed that 82% of the sportfishermen ate the white croaker they caught and the median consumption was 14.8 g day^?1 person^?1. White croaker were then sampled by hook-and-line from 11 of the 12 survey sites plus two control sites and analysed for PCB, DDT and BaP. Median PCB levels ranged from 0.014 to 0.41 mg wet kg^?1; median DDT from 0.059 to 7.5 mg wet kg^?1 and BaP was below detectable limits of 1 ng for all sites.  相似文献   

山东山旺盆地中新世两个蚂蚁新属（Heteromyrmex Zhang,1989和Tolylasius Zhang,1989）的修正     

洪友崇  吴坚等 《地质论评》2001,47(4):345-349

1989年,张俊峰发表了山东山旺盆地中新世（N2）2个蚂蚁新属新种：Heteromyrmex atopogaster Zhang,1989和Tolylasius inflatus Zhang,1989。经检验,前一个属是基于不实的观察结果,新属、种应予废除,作为未定属种归人蚁亚科（Formicinae);后一个属的建属根据都非建属的根据,其他的特征系毛蚁属（Lasius)的属征范围,没有建属条件,属应予废,保留其种,转移到毛蚁属。  相似文献   

张广才岭燕山早期白石山岩体成因与壳幔相互作用   总被引：34，自引：19，他引：34  

孙德有  吴福元  林强  路孝平 《岩石学报》2001,17(2):227-235

出露于东北地区张广才岭的白石山岩体,其全岩-矿物Rb-Sr等时线年龄为196士4 Ma,表明形成于中生代的燕山早期,而非传统认识上的印支期.岩体主岩和闪长质包体均具有低ISr(≈0.705)和正εNd(t)(+1.7～+2.2)值的特点,反映岩体成因与地幔具有密切的联系.地质学、岩石学和地球化学的详细研究表明该岩体具有壳幔混合成因,闪长质包体是较基性的地幔岩浆进入主岩浆中淬火结晶而成,花岗质岩浆的源区主要为新生的地壳物质.动力学分析表明,本区在华北板块和西伯利亚板块碰撞拼合后,由于东侧大洋板块的俯冲及后续的岩石圈拆沉效应,导致软流圈地幔上隆及幔源岩浆的板底垫托,并进而造成先存和新生地壳的部分熔融和不同源区岩浆的混合作用.底垫的新生地壳是兴蒙造山带造山后晚期形成的.因此,古生代-中生代是本区地壳生长的重要时期,且这种地壳生长是在垂向构造机制下进行的.  相似文献   

Holocene History of the Bering Sea Bowhead Whale (Balaena mysticetus) in Its Beaufort Sea Summer Grounds off Southwestern Victoria Island, Western Canadian Arctic     

Arthur S. Dyke  James M. Savelle 《Quaternary Research》2001,55(3):371

The fossil remains of 43 bowhead whales were mapped on the raised beaches of western Wollaston Peninsula, Victoria Island, Canadian Arctic, near the historic summer range limit of the Bering Sea stock in the Beaufort Sea. The elevations and radiocarbon ages of the remains demonstrate that the bowhead ranged commonly into the region following the submergence of Bering Strait at ca. 10,000 ¹⁴C yr B.P. until ca. 8500 ¹⁴C yr B.P. During the same interval, bowheads ranged widely from the Beaufort Sea to Baffin Bay. Subsequently, no whales reached Wollaston Peninsula until ca. 1500 ¹⁴C yr B.P. Late Holocene populations evidently were small, or occupations were brief, in comparison to those of the early Holocene. Although the late Holocene recurrence may relate to the expansion of pioneering Thule whalers eastward from Alaska, there are few Thule sites and limited evidence of Thule whaling in the area surveyed to support this suggestion.  相似文献   

Reply to Russell Graham about Mustela macrodon     

Jim I Mead  Arthur E Spiess 《Quaternary Research》2001,56(3):422

  相似文献