一种新的适合富有机质沉积岩的Re-Os同位素分析方法初探
A new method for analysis of Re-Os isotopic system in organic-rich sediments
查看参考文献31篇
|
文摘
|
虽然富有机质沉积岩中的Re和Os主要都富集在有机质中,但其中碎屑部分中的Re和Os也会影响其Re-Os等时线的准确度和精度。目前最常用的CrO_3-H_2SO_4溶样法虽然能尽量避免碎屑物质中Re和Os的溶出,但该方法具有Re流程空白高和环境污染严重等问题。因此,本研究尝试在富有机质沉积岩Re-Os同位素分析中使用H_2O_2-HNO_3溶样来代替CrO_3-H_2SO_4溶样。本研究利用国际油页岩标样SGR-lb(USGS)为实验研究对象,分别对HCl-HNO_3溶样、CrO_3-H_2SO_4溶样和H_2O_2-HNO_3溶样3种溶样方法进行了对比研究。研究表明,H_2O_2与HNO_3的体积比约为5: 1的H_2O_2-HNO_3溶液,不仅能保证样品和稀释剂的Re、Os同位素达到同位素交换平衡而且尽可能地避免碎屑物质中Re和Os的溶出。本方法相比于HCl-HNO_3溶样,能尽量避免碎屑物质中Re和Os的溶出;而相比于CrO_3-H_2SO_4溶样,该方法具有本底低、无污染的优点。最后利用H_2O_2-HNO_3溶样方法对广西金秀地区的泥岩样品和广东大宝山地区的碳质页岩样品进行了Re-Os同位素定年分析,分别得到了(404±5) Ma (I_(Os)=1.57±0.13, n=8, MSWD=50)和(211±11) Ma (I_(Os)=0.67±0.09, n=5,MSWD=11.1)的等时线年龄,这一结果与HCl-HNO_3溶样得到的结果((412±11) Ma, I_(Os)=1.18±0.38, n=8,MSWD=311; (223±18) Ma, I_(Os) = 0.59±0.14,n=5,MSWD=63)在误差范围内一致,但更为精确。 |
|
其他语种文摘
|
Rhenium and osmium in organic-rich sedimentary rocks are dominantly enriched in organics, but Re-Os components left in clasts of these rocks will certainly influence the accuracy and precision of the Re-Os isochron generally obtained. The commonly used CrO_3-H_2SO_4 digestion method can minimize the influence of any clast-originated Re and Os, but this medium is restricted by high reagent blank and environmental pollution issues. Therefore, we employ H_2O_2-HNO_3 digestion medium instead of CrO_3-H_2SO_4. We evaluate bulk rock analysis using H_2O_2-HNO_3 digestion medium together with HCl-HNO_3 and CrO_3-H_2SO_4, for international standard sample SGR-lb. The results of Re-Os dating indicate that the H_2O_2-HNO_3 medium with a volume ratio of H_2O_2 to HNO_3 being 5: 1 can allow tracer-sample equilibration via complete oxidation of all Os species, and can also minimize the influence of any non-organic derived Re and Os. Meanwhile, the H_2O_2-HNO_3 medium shows a lower reagent blank and proves to be environmentally friendly. The H_2O_2-HNO_3 digestion technique was used for Re-Os dating of mudstone from Jinxiu, Guangxi Province and carbonaceous shale from Dabao Mountain in Guangdong Province. Compared with the dating results of aqua regia digestion technique, more precise isochron ages of (404±5) Ma with initial ~(187)Os/~(188)Os ratio of 1.57±0.13 (n=8, MSWD=50) and of (211±11) Ma with initial ~(187)Os/~(188)Os ratio of 0.67±0.09 (n=5, MSWD=11.1) were obtained by H_2O_2-HNO_3 digestion technique. |
|
来源
|
地球化学
,2015,44(3):225-237 【核心库】
|
|
关键词
|
富有机质沉积岩
;
Re-Os同位素定年
;
三氧化铬-浓硫酸
;
双氧水-硝酸
;
溶样方法
|
|
地址
|
1.
中国科学院广州地球化学研究所, 同位素地球化学国家重点实验室, 广东, 广州, 510640
2.
国家地质实验测试中心, 北京, 100037
|
|
语种
|
中文 |
|
文献类型
|
研究性论文 |
|
ISSN
|
0379-1726 |
|
学科
|
地质学 |
|
基金
|
同位素地球化学国家重点实验室技术研发基金
;
国家自然科学基金
|
|
文献收藏号
|
CSCD:5424536
|
参考文献 共
31
共2页
|
|
1.
Peucker-Ehrenbrink B. The marine osmium isotope record.
Terra Nova,2000,12(5):205-219
|
被引
24
次
|
|
|
|
|
2.
Yamashita Y. Comparison of reductive accumulation of Re and Os in seawater-sediment systems.
Geochim Cosmochim Acta,2007,71(14):3458-3475
|
被引
16
次
|
|
|
|
|
3.
李超. 富有机质地质样品Re-Os同位素体系研究进展.
岩石矿物学杂志,2010,29(4):421-430
|
被引
23
次
|
|
|
|
|
4.
李超. Re-Os同位素在沉积地层精确定年及古环境反演中的应用进展.
地球学报,2014,35(4):405-414
|
被引
20
次
|
|
|
|
|
5.
沈传波. 油气成藏定年的Re-Os同位素方法应用研究.
矿物岩石,2012,31(4):87-93
|
被引
1
次
|
|
|
|
|
6.
Ravizza G. Application of the ~(187)Re-~(187)Os system to black shale geochronometry.
Geochim Cosmochim Acta,1989,53(12):3257-3262
|
被引
28
次
|
|
|
|
|
7.
Ravizza G. The geochemistry of rhenium and osmium in recent sediments from the Black Sea.
Geochim Cosmochim Acta,1991,55(12):3741-3752
|
被引
19
次
|
|
|
|
|
8.
Ravizza G. A possible link between the seawater osmium isotope record and weathering of ancient sedimentary organic matter.
Chem Geol,1993,107(3):255-258
|
被引
7
次
|
|
|
|
|
9.
Cohen A S. Precise Re-Os ages of organic-rich mudrocks and the Os isotope composition of Jurassic seawater.
Earth Planet Sci Lett,1999,167(3):159-173
|
被引
40
次
|
|
|
|
|
10.
Jaffe L A. Mobility of rhenium, platinum group elements and organic carbon during black shale weathering.
Earth Planet Sci Lett,2002,198(3):339-353
|
被引
32
次
|
|
|
|
|
11.
Ripley E M. Re-Os isotopic composition and PGE contents of Proterozoic carbonaceous argillites, Virginia Formation, Northeastern Minnesota.
Org Geochem,2001,32(6):857-866
|
被引
3
次
|
|
|
|
|
12.
Ripley E M. Re-Os isotopic variations in carbonaceous pelites hosting the Duluth Complex: Implications for metamorphic and metasomatic processes associated with mafic magma chambers.
Geochim Cosmochim Acta,2001,65(17):2965-2978
|
被引
3
次
|
|
|
|
|
13.
Selby D. Re-Os geochronology of organic rich sediments: An evaluation of organic matter analysis methods.
Chem Geol,2003,200(3):225-240
|
被引
28
次
|
|
|
|
|
14.
Kendall B S. Constraints on the timing of Marinoan "Snowball Earth" glaciation by ~(187)Re-~(187)Os dating of a Neoproterozoic, post-glacial black shale in Western Canada.
Earth Planet Sci Lett,2004,222(3):729-740
|
被引
23
次
|
|
|
|
|
15.
Shen J J. Precise Re-Os determinations and systematics of iron meteorites.
Geochim Cosmochim Acta,1996,60(15):2887-2900
|
被引
37
次
|
|
|
|
|
16.
Kendall B. Re-Os and Mo isotope systematics of black shales from the Middle Proterozoic Velkerri and Wollogorang formations, McArthur Basin, northern Australia.
Geochim Cosmochim Acta,2009,73(9):2534-2558
|
被引
29
次
|
|
|
|
|
17.
王剑. 羌塘盆地胜利河海相油页岩地球化学特征及Re-Os定年.
海相油气地质,2007,12(3):21-26
|
被引
35
次
|
|
|
|
|
18.
刘华. 用三氧化铬-硫酸溶剂对黑色页岩铼-锇定年方法初探.
岩矿测试,2008,27(4):245-249
|
被引
15
次
|
|
|
|
|
19.
Li J. Determination of platinum-group elements and Re-Os isotopes using ID-ICP-MS and N-TIMS from a single digestion after two-stage column separation.
Geostand Geoanal Res,2014,38(1):37-50
|
被引
20
次
|
|
|
|
|
20.
Li J. Reassessment of hydrofluoric acid desilicification in the Carius tube digestion technique for Re-Os isotopic determination in geological samples.
Geostand Geoanal Res,2014,39(1):17-30
|
被引
3
次
|
|
|
|
|
了解气象卫星更多信息，请访问