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191.
Hydrous pyrolysis (closed vessel autoclaving in the presence of excess water) of organic-rich rocks is said to generate oils which closely resemble natural crude oils in their broad characteristics and composition. However there are only a few accounts of the proportions and compositions of hydrocarbons in hydrous pyrolysates and none of these discuss the aromatic hydrocarbon composition in detail. The present paper presents some data on the latter.Hydrous pyrolysis (3 days) of a dolomitic siltstone (Permian, Marl Slate) at 280, 300,320, 340 and 360°C produced significant amounts of oils in which the aromatic hydrocarbons were one and a half to two times as abundant as the saturated hydrocarbons.The overall composition of the aromatic hydrocarbons was similar to most crude oils; the major components isolated by our methods from natural oils and from pyrolysates were C1–4 alkylnaphthalenes. At the lowest pyrolysis temperature (280°C) the distributions of the more minor components of the pyrolysates (e.g. alkylphenanthrenes, aromatic steroids) were also generally similar to those found in natural crudes. However, a number of components (e.g. methylanthracenes, Diels' hydrocarbon) which are not usually reported in crudes, were also detected and the relative proportions of these increased at the higher temperatures. Hydrous pyrolysis (340°C) of an organic-rich oil shale (Jurassic, Kimmeridge) and an asphaltic-material containing no minerals produced pyrolysates in which many of these unusual compounds were also present. In addition the pyrolysate of the oil-shale contained higher proportions of organic sulphur compounds. It appears that the formation of the unusual compounds is not simply a function of the type of organic matter or mineralogy but rather of the high temperatures or fast heating rates employed. 相似文献
192.
利用闪电定位仪每分钟实测资料、加密自动站逐分钟雨量和卫星云图云顶亮温TBB资料,对2013年4月29日西南涡东移过程中MCS产生的局地暴雨地闪特征进行了分析。结果表明:这次过程产生了大量地闪活动,且地闪主要出现在西南涡东侧500 hPa槽前辐合上升运动区、700 hPa暖切南侧850 hPa暖切北部的辐合带、TBB小于等于220 K区域南侧TBB水平梯度大值区的叠置区。整个过程负闪占主导地位,强降水发生在负闪密集区;MCS生命史不同阶段的正负闪频数、密集程度和分布位置是不同的。进一步分析发现单站地闪频数与TBB和强降水在时空变化上有一定的相关性,地闪频数和TBB表现为负相关,即TBB下降到最低值时,地闪频数则到达峰值;逐时地闪频数和雨强均呈单峰分布,负闪频数和强降水发展演变趋势一致,负闪峰值和最大雨峰时刻对应,正闪或和最大雨峰一致或略滞后,正负闪和雨峰的6 min演变趋势呈多峰分布,负闪初现12~18 min后出现降水,负闪突增较强降水有18~24 min的提前量。此个例显示MCS将朝向移动路径前侧的负闪密集区域移动,负闪密集区对局地强降水的落区和强度有较好的指示意义。 相似文献
193.
Late Triassic–Early Jurassic intrusions of the Erguna Block, Northeast China, are located along the southern margin of the Mongol–Okhotsk orogenic belt. They comprise granodiorite, monzogranite, syenogranite, and lesser gabbro–diorite, of adakitic and calcalkaline affinity. The adakite-like and calcalkaline granites share similar light rare earth elements (LREE) characteristics; however, their heavy rare earth elements (HREE) trends differ from one another. The relative abundances of HREE in the calcalkaline granites are relatively consistent and are similar to those of intrusive rocks formed from dehydration melting of garnet-free amphibolitic source rocks at relatively low pressures. In contrast, the adakite-like granites show more prominent HREE fractionation trends, indicating that they crystallized at higher pressures, where garnet in the source rocks was stable. At least two isotopically distinct sources were involved in the petrogenesis of the granites, but the extent to which they contributed varies between plutons. Most intrusions have incorporated an isotopically primitive component, possibly juvenile mafic crust. The other sources include a small proportion of old continental crustal material and isotopically evolved wall rocks. The gabbro–diorites have high MgO contents (>7 wt.%), a high Mg# (>0.6), and show moderate LREE and HREE fractionation, indicating they formed from the melting of subducted metasomatized lithospheric mantle. All of the intrusions in the study area are characterized by a relative enrichment in large ion lithophile elements (LILE) and depletion in high field strength elements (HFSE), indicating they were emplaced in an Andean-type active continental margin setting related to southward subduction of the Mongol–Okhotsk oceanic plate. 相似文献