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101.
102.
Lutz Nasdala Wolfgang Hofmeister Nicholas Norberg James M. Martinson Fernando Corfu Wolfgang Dörr Sandra L. Kamo Allen K. Kennedy Andreas Kronz Peter W. Reiners Dirk Frei Jan Kosler Yusheng Wan Jens Götze Tobias Häger Alfred Kröner John W. Valley 《Geostandards and Geoanalytical Research》2008,32(3):247-265
We introduce and propose zircon M257 as a future reference material for the determination of zircon U‐Pb ages by means of secondary ion mass spectrometry. This light brownish, flawless, cut gemstone specimen from Sri Lanka weighed 5.14 g (25.7 carats). Zircon M257 has TIMS‐determined, mean isotopic ratios (2s uncertainties) of 0.09100 ± 0.00003 for 206pb/238U and 0.7392 ± 0.0003 for 207pb/235U. Its 206pb/238U age is 561.3 ± 0.3 Ma (unweighted mean, uncertainty quoted at the 95% confidence level); the U‐Pb system is concordant within uncertainty of decay constants. Zircon M257 contains ~ 840 μg g?1 U (Th/U ~ 0.27). The material exhibits remarkably low heterogeneity, with a virtual absence of any internal textures even in cathodoluminescence images. The uniform, moderate degree of radiation damage (estimated from the expansion of unit‐cell parameters, broadening of Raman spectral parameters and density) corresponds well, within the “Sri Lankan trends”, with actinide concentrations, U‐Pb age, and the calculated alpha fluence of 1.66 × 1018 g?1. This, and a (U+Th)/He age of 419 ± 9 Ma (2s), enables us to exclude any unusual thermal history or heat treatment, which could potentially have affected the retention of radiogenic Pb. The oxygen isotope ratio of this zircon is 13.9%o VSMOW suggesting a metamorphic genesis in a marble or calc‐silicate skarn. 相似文献
103.
Taeko Shinonaga Helmuth Aigner Dilani Klose Peter Spinder Heinz Fröschl David Donohue 《Geostandards and Geoanalytical Research》2008,32(1):93-101
The recommended concentrations of 239Pu, 240Pu and 239+240Pu in reference material IAEA‐315 (marine sediment) were estimated by three analytical methods: isotope dilution thermal ionisation mass spectrometry (TIMS), isotope dilution inductively coupled plasma‐mass spectrometry (ICP‐MS) and alpha spectrometry. The determination of 239Pu and 240Pu (239+240Pu by alpha spectrometry) was carried out with samples from randomly selected bottles using each method. Plutonium‐238 was also measured by alpha spectrometry. A plutonium‐242 reference material was used as a spike for the quantitative analysis. The influence of 242Pu in the samples was therefore calculated; however, this contribution was less than the range of uncertainty and did not influence the final results. The obtained data were statistically analysed using variance component analysis and paired comparison. The combined standard uncertainties from “method/measurement”, “bottle” and “sub‐sample” were in the order of 3 to 6%. The main contributions to the uncertainty were from the material heterogeneity and from systematic differences between methods. Based on this study with twenty‐seven analyses using 10–14 g sample mass, concentrations of (38 ± 3) Bq kg?1, (28 ± 3) Bq kg?1 and (66 ± 4) Bq kg?1 are proposed as recommended values for 239Pu, 240Pu and 239+240Pu, respectively, and (9.5 ± 0.4) Bq kg?1 for 238Pu as an information value in reference material IAEA‐315. In mass concentration units, these amount to (16.4 ± 1.2) ng kg?1, (3.3 ± 0.4) ng kg?1 and (0.015 ± 0.003) ng kg?1 for 239Pu, 240Pu and 238Pu, respectively. The certified reference materials NIST 4350B and NIST 4354 were also analysed by TIMS for quality assurance of the method used in this study. 相似文献
104.
应用生烃动力学法研究川东上二叠统烃源岩生烃史 总被引:3,自引:2,他引:1
现今川东上二叠统烃源岩生烃史研究具有局限性.首先,没有对上二叠统Ⅰ-Ⅱ1型灰岩生油、Ⅲ型泥岩的生气史分开评价;其次,海相镜质组反射率通过拟合公式换算成镜质体反射率评价烃源岩成熟度具有局限性.针对上述不足,笔者通过热模拟实验,利用化学动力学方法,标定出两类源岩生油、生气的动力学参数,并结合川东地区的埋藏史及热史,模拟出源岩有机质的成烃转化率曲线.研究表明:上二叠统灰岩、泥岩有机质在距今200 Ma和190 Ma分别进入了生油、生气门限,而在距今170 Ma和140 Ma生烃结束. 相似文献
105.
Rock magnetic record of Cenozoic lake sediments from the Linxia basin and aridification of the Asian inland 总被引:1,自引:0,他引:1
High resolution research of rock magnetic records and quartz sands from the Maogou Section in the Linxia basin reveals that
after a relatively stable environment between 13.07 Ma and 8.6 Ma, the basin was gradually influxed by eolian dusts at about
8.6 Ma, with two rapid increases at about 6.4 Ma and 5.3 Ma, respectively. The study suggests that drying of northwest China
began at 8.6 Ma and strengthened rapidly at about 6.4 Ma and 5.3 Ma.
__________
Translated from Marine geology & Quaternary geology, 2007, 27(4): 103–110 [译自: 海洋地质与第四纪地质] 相似文献
106.
Zhanhong LIU Sitian LI Renchen XIN Changgui XU Jianchun CHENG 《Frontiers of Earth Science》2008,2(1):73-82
Bohaiwan basin, covering an area of 200 000 km2, is one of the most important oil-bearing basins in Eastern China. Rifting processes formed the basin, and two evolution
phases can be recognized. The rifting phase developed in Paleogene, and post-rifting phase occurred in Neogene. More than
200 oil fields have been found in the onshore and offshore area in Bohaiwan basin in recent years. The distribution of the
oil fields is closely related to the rich hydrocarbon depressions, and the Huanghekou depression is one of these rich hydrocarbon
depressions. A number of large and medium-sized oil and gas fields have been found in this area, such as BZ25-1, BZ34 etc.,
and the hydrocarbon was mainly from the Huanghekou depression. The formation of rich hydrocarbon source rocks depended on
the tectonic setting of rapid subsidence, favorable paleoclimatic conditions and paleolimnology environments. The effects
of paleoclimatic condition on hydrocarbon source rocks are the focus of this paper.
__________
Translated from Geological Bulletin of China, 2007, 26(7): 830–840 [译自: 地质通报] 相似文献
107.
青藏高原羌D2井海相烃源岩评价和油源对比 总被引:1,自引:0,他引:1
南羌塘坳陷D2井中侏罗统曲布组海相碳酸盐岩大部分为差—好烃源岩级别,少部分为非烃源岩级别,有机质母质类型以Ⅱ型为主,热演化处于成熟—高成熟阶段。油源对比分析表明,羌D2井曲布组白云岩和含沥青角砾岩中油质沥青来自该组地层灰岩烃源岩,具自生自储性质。同时,中侏罗统雀莫错组灰黑色泥页岩作为烃源层也存在提供油源的可能性。 相似文献
108.
封闭体系有机质与有机碳氢氮恢复动力学研究 总被引:3,自引:0,他引:3
在封闭体系的条件下,对典型的Ⅰ、Ⅱ、Ⅲ型干酪根在热演化过程中的损失进行生烃动力学研究,获得了Ⅰ、Ⅱ、Ⅲ型干酪根的总量、有机碳、氢以及氮质量损失动力学参数。用Kinetics软件计算了封闭体系干酪根有机碳丰度、氢碳原子比和氮碳原子比的恢复系数。认为在对高成熟—过成熟干酪根进行生烃评价时,Ⅰ、Ⅲ型干酪根残余有机碳丰度需要进行恢复,而Ⅱ型干酪根残余有机碳丰度不需要恢复。三种类型干酪根的氢碳原子比均需要进行恢复。 相似文献
109.
我国古生代海相碳酸盐岩成藏理论的新进展 总被引:1,自引:0,他引:1
近年来在中国古生界新发现大中型油气田40多个,其中大型油气田16个。在长期研究中国古生代海相沉积特征的基础上,总结归纳近几年来新发现的海相烃源岩,提出对碳酸盐岩有效烃源岩的新认识。从有效烃源岩、古岩溶储集体、油气成藏期次和成藏模式等四个方面概述油气成藏理论方面的新进展;根据油气成藏史研究,结合区域构造演化史、生烃史等,提出塔河油田奥陶系有四个成藏期:加里东中晚期至海西早期;海西晚期;燕山期-喜马拉雅早中期;喜马拉雅晚期。 相似文献
110.
金岭寺—羊山盆地北票组烃源岩特征 总被引:2,自引:0,他引:2
通过对采集的岩样进行地球化学综合分析,得出金羊盆地北票组为盆地主要烃源岩,为盆地油气生成提供了物质基础;北票组烃源岩有机质丰度不高,属差一中等烃源岩;干酪根类型以腐殖型为主,成烃母质为陆地高等植物:金羊盆地北票组烃源岩已经进入成烃门限.并处于成熟阶段中的低成熟到中成熟阶段。 相似文献