本文關(guān)鍵詞：Hf-Fe同位素分析方法及其在騰沖火山巖研究中的應(yīng)用　出處：《中國(guó)科學(xué)技術(shù)大學(xué)》2016年博士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 放射成因同位素Hf 金屬穩(wěn)定同位素Fe 化學(xué)分離 MC-ICP-MS 同位素標(biāo)準(zhǔn)物質(zhì) 同位素示蹤 騰沖火山巖 大陸巖石圈地幔

【摘要】：近年來,隨著同位素測(cè)試技術(shù)的革新以及現(xiàn)代分析儀器的開發(fā)和推廣,同位素分析方法(包括放射成因同位素分析和穩(wěn)定同位素分析)迅速發(fā)展,已成為地學(xué)研究中一門重要的分析技術(shù)。殼-幔體系中,放射成因同位素鉿(Hf)在示蹤源區(qū)特征及演化過程方面,能比傳統(tǒng)鍶-釹-鉛(Sr-Nd-Pb)同位素提供更好的觀察視角：金屬穩(wěn)定同位素鐵(Fe)依據(jù)同位素分餾規(guī)律,在示蹤巖石成因上具有顯著優(yōu)勢(shì),現(xiàn)已成為一種新的地球化學(xué)示蹤劑�；谕凰胤治龇椒ㄅ畈l(fā)展的大背景下,并結(jié)合放射成因同位素和金屬穩(wěn)定同位素的獨(dú)特示蹤優(yōu)勢(shì),我們?cè)贖f-Fe同位素聯(lián)合分析方法及地質(zhì)應(yīng)用方面開展了一系列工作,以期更精確地揭示巖石的源區(qū)特征和殼-幔相互作用,為同位素地球化學(xué)領(lǐng)域開辟一條新的研究思路。本論文主要從以下四個(gè)方面展開：(1)Hf、Fe同位素分析方法研究進(jìn)展隨著多接收電感耦合等離子體質(zhì)譜(MC-ICP-MS)的發(fā)展,同位素分析方法出現(xiàn)重大突破。本部分綜述了Hf、Fe同位素分析技術(shù)的發(fā)展歷程,Hf、Fe化學(xué)分離方法的研究進(jìn)展以及質(zhì)譜測(cè)定的影響因素�？v觀前人研究,Hf和Fe獨(dú)立的化學(xué)分離方法已經(jīng)日趨成熟,并被廣泛應(yīng)用于國(guó)內(nèi)、外各大實(shí)驗(yàn)室。此外,MC-ICP-MS已成為當(dāng)前Hf、Fe同位素組成測(cè)定的主流方法。(2)建立“同一巖樣Hf-Fe化學(xué)分離方法”前人研究表明,主量元素Fe對(duì)Hf同位素分析會(huì)產(chǎn)生巨大的干擾(如聚合物干擾、基質(zhì)效應(yīng)等),如何從Hf待測(cè)溶液中徹底去除Fe是一個(gè)亟待解決的問題。然而,近年來Hf-Fe同位素聯(lián)合分析在高溫地質(zhì)應(yīng)用中的潛在價(jià)值逐漸被發(fā)現(xiàn)。由此,我們提出一個(gè)設(shè)想：是否能從同一份地質(zhì)樣品中分離、純化出Hf和Fe?如此,不但能消除Fe對(duì)Hf的干擾,還能就一份巖樣同時(shí)獲得它們的Hf、Fe同位素信息,進(jìn)而達(dá)到Hf-Fe同位素聯(lián)合分析的目的�；谇叭霜�(dú)立的Hf、Fe分離理念,我們?cè)O(shè)計(jì)出一套簡(jiǎn)單且高效的Hf-Fe多元素化學(xué)分離流程。這是一套離子交換色譜法和提取色譜法相結(jié)合的兩階段分離流程,先通過Bio-Rad AG-MP-1M陰離子交換樹脂從充分溶解的巖液中分離獲得Fe元素,再將所接收到的含Hf基質(zhì)溶液經(jīng)Eichrom LN-Spec樹脂進(jìn)一步分離純化出Hf元素。值得一提的是,本流程除了能徹底分離Hf和Fe之外,還可以根據(jù)需要,進(jìn)一步分離純化出Lu、Rb、Sr、Sm、Nd、Pb等多種元素,能夠就同一份樣品提供更多的同位素信息。(3)確立“合適的Hf、Fe同位素標(biāo)準(zhǔn)物質(zhì)”準(zhǔn)確可靠的同位素標(biāo)準(zhǔn)物質(zhì)是支撐同位素分析技術(shù)發(fā)展的一個(gè)重要保證。然而,就Hf、Fe同位素分析而言,國(guó)際標(biāo)準(zhǔn)物質(zhì)的供不應(yīng)求很大程度上阻礙了該技術(shù)的推廣。同時(shí),一種新Hf、Fe國(guó)際標(biāo)準(zhǔn)的建立,不僅難度大且耗時(shí)長(zhǎng)。因此,人們嘗試從現(xiàn)有的元素標(biāo)準(zhǔn)物質(zhì)中尋找適合用于同位素分析的“內(nèi)部標(biāo)準(zhǔn)”,來協(xié)助國(guó)際標(biāo)準(zhǔn)一起完成常規(guī)測(cè)試�；诖�,我們首次對(duì)三種國(guó)家火成巖一級(jí)標(biāo)準(zhǔn)物質(zhì)(GSR-1花崗巖：GSR-2安山巖;GSR-3玄武巖)進(jìn)行了系統(tǒng)的Hf、Fe同位素分析,判定它們是否適合用作Hf、Fe同位素分析的“內(nèi)部標(biāo)準(zhǔn)”。分析結(jié)果表明,GSR-2和GSR-3均適合用作Hf同位素分析的內(nèi)部標(biāo)準(zhǔn),相應(yīng)的同位素組成推薦值分別為176Hf/177Hf=0.282641±6 (MSWD=1.5,2σ, n=10)和176Hf/177Hf=0.282985±4 (MSWD=0.48,2σ, n=10)。但是,GSR-1花崗巖可能因繼承鋯石而表現(xiàn)出同位素組成上的不均一,由此,它不適合用作Hf同位素標(biāo)準(zhǔn)物質(zhì)。此外,GSR-1, GSR-2和GSR-3均適合用作Fe同位素分析的內(nèi)部標(biāo)準(zhǔn),它們的同位素推薦值657Fe分別為+0.35±0.02‰,+0.22±0.05‰,+0.43±0.02‰(相對(duì)于IRMM-014,2σ,n=3)。(4)晚新生代騰沖火山巖Hf-Fe-(Sr-Nd-Pb)同位素示蹤中國(guó)西南部騰沖火山區(qū)分布著眾多新生代鎂鐵質(zhì)大陸板內(nèi)火山巖,該區(qū)共有68座具有明顯火山錐山體的火山,熔巖的分布面積約為800平方公里。結(jié)合前人已有的報(bào)道,我們對(duì)該區(qū)18個(gè)新鮮的火山巖樣品進(jìn)行了主、微量元素和Hf-Fe-Sr-Nd-Pb多種同位素的綜合分析,旨在深入探究騰沖火山巖的源區(qū)特征以及巖漿演化過程。研究表明,這批火山巖中大部分樣品均經(jīng)歷過分離結(jié)晶-同化混染作用(AFC)。其中,一些混染較為明顯的樣品,表現(xiàn)出極異常的輕Fe同位素特征,推測(cè)代表了混染的大陸地殼特征。依據(jù)主、微量元素、AFC演化趨勢(shì)以及Hf-Nd同位素特征等多方證據(jù),我們識(shí)別出三個(gè)樣品具有初始巖漿特征,可能直接來源于地幔源區(qū),它們的Hf-Fe-Sr-Nd-Pb同位素組成(176Hf/177Hf=0.282962, δ56Fe=0.13‰,87Sr/86Sr=0.705861,143Nd/144Nd=0.512675,206Pb/204Pb=18.305, 207Pb/204Pb=15.642,208Pb/204Pb=38.948)能夠代表中國(guó)西南部騰沖地幔源區(qū)的特征。通過“熔融模擬”實(shí)驗(yàn),我們認(rèn)為騰沖火山的最佳成因模型可以表示為：受到過交代的地幔源區(qū)(由95-99%的原始虧損地幔(DMM)和1-5%的全球俯沖沉積物(GLOSS)構(gòu)成)經(jīng)歷1-4%的部分熔融后形成騰沖原始巖漿。這些具有富集地幔特征的原始巖漿可能來自俯沖相關(guān)的交代巖石圈地幔。因此,騰沖火山巖的地幔源區(qū)與前人提出的富集地幔端員(如EM1,EM2)或DUPAUL地幔沒有直接的聯(lián)系,它們只是具有相似的同位素特征。此外該區(qū)缺少地幔柱存在的證據(jù),我們推測(cè)騰沖火山作用是在“與印度次大陸反向應(yīng)力有關(guān)”的伸展背景下,熱的富集大陸巖石圈地幔被動(dòng)上涌所觸發(fā)的。由于受交代的富集地幔組分容易發(fā)生熔融,騰沖火山巖即是該區(qū)大陸巖石圈地幔富集組分減壓熔融后的產(chǎn)物。
[Abstract]:In recent years, with the development and popularization of isotope test innovative technology and modern analytical instruments, methods of isotope analysis (including analysis of radiogenic isotope analysis and stable isotope) rapid development, has become an important research in the analysis. The crust mantle system, radiogenic isotope characteristics in HF (Hf) and the evolution of tracer source region process, energy than conventional SR nd Pb (Sr-Nd-Pb) provides a better perspective: metal isotope stable isotope of iron (Fe) on the basis of isotopic fractionation law, has a significant advantage in tracing the petrogenesis, has become a new geochemical tracer. Based on the background of rapid isotope analysis method the development, combined with the unique advantages of radiogenic isotope tracer and metal isotope, Hf-Fe isotope in our joint analysis method and geological application aspects carried out a series of Out of work, in order to more accurately reveal the feature of source rock and crust mantle interaction, open up a new way for the research of isotope geochemical field. This thesis mainly from the following four aspects: (1) Hf, with the research method of receiving power inductively coupled plasma mass spectrometry (Fe isotope analysis MC-ICP-MS) the development of methods to breakthrough isotopic analysis. This part reviews the development course of Hf technology, Fe Hf isotope analysis, the factors influencing the determination of Fe chemical separation methods and research progress of mass spectrometry. In previous studies, Hf and Fe independent chemical separation method has become increasingly mature, and widely used in domestic and outside of the major laboratory. In addition, MC-ICP-MS has become the mainstream method for the determination of Hf, Fe isotopic compositions. (2) the establishment of "the same" previous research samples for chemical separation of Hf-Fe showed that the main elements of Hf in Fe Analysis will produce huge interference (such as polymer matrix interference effect), how to completely remove the Fe test solution is an urgent problem to be solved in Hf. However, in recent years the Hf-Fe isotope combined analysis of potential value in high temperature geological application has been found. Therefore, we proposed a hypothesis: whether can be separated from the same geological samples, purified Hf and Fe? So, not only can eliminate the interference of Fe to Hf, but also a specimen obtained at the same time their Hf, Fe isotope information, and then reach a combined analysis of Hf-Fe isotopes. Based on the previous independent Hf, Fe separation principle, we design a simple and efficient Hf-Fe multi element chemical separation process. This is the two stage of a combination of ion exchange chromatography and extraction chromatography separation process, from the first through the rock fluid to fully dissolve Bio-Rad AG-MP-1M anion exchange resin Isolated Fe element, then Hf matrix solution containing received by Eichrom LN-Spec resin was further purified by Hf elements. It is worth mentioning that this process in addition to the complete separation of Hf and Fe, can also according to the needs of the purified Lu, Sr, Sm further separation of Rb, Nd, Pb. And other elements, can provide more information on the same isotope samples. (3) establish appropriate Hf isotope reference material Fe isotope standard material accurate and reliable is an important guarantee for technology development of isotopic analysis support. However, Hf, Fe isotope analysis, international standard material in a large extent hindered the popularization of this technology. At the same time, a new Hf, the establishment of Fe international standard, not only is difficult and time-consuming. Therefore, people try to find suitable for isotopic analysis of internal standard elements from existing standard materials "To assist the international standard together with the completion of routine testing. Based on this, we for the first time on the three kinds of national standard substances of igneous rocks (granite GSR-1: GSR-2 andesite; GSR-3 basalt) of the system Hf, Fe isotope analysis, determine whether they are suitable for Hf, Fe isotope analysis of the" internal standard ". The analysis results show that GSR-2 and GSR-3 are suitable for Hf isotopic analysis of the internal standard, the corresponding isotopic composition of recommended values were 176Hf/177Hf=0.282641 + 6 (MSWD=1.5,2 6, n=10) and 176Hf/177Hf=0.282985 (MSWD=0.48,2 + 4 sigma, n=10). However, the GSR-1 granite may be due to inherited zircons show the isotopic composition of the heterogeneity, thus and it is not suitable for Hf isotope reference material. In addition, GSR-1, GSR-2 and GSR-3 are suitable for Fe isotopic analysis of the internal standard, their isotopic recommended value of 657Fe were +0.35 + 0.02 %, +0.22% + 0.05, +0.43 + 0.02% (relative to IRMM-014,2 sigma, n=3). (4) late Cenozoic volcano rock of Tengchong Hf-Fe- (Sr-Nd-Pb) Chinese isotope tracer in southwest Tengchong volcano area distribution of volcano rock many Cenozoic mafic continental intraplate region, the total of 68 cities has obvious volcano cone the mountain volcano, lava distribution area is about 800 square kilometers. According to previous reports, we conducted principal of volcano rock samples fresh 18 in this area, a comprehensive analysis of trace elements and Hf-Fe-Sr-Nd-Pb isotopes, probes into the Tengchong volcano rock source characteristics and magmatic evolution process. The results show that the most of the samples in the volcano rock group experienced fractional crystallization - assimilation effect (AFC). Among them, some of the more obvious contamination samples showed light Fe isotopic characteristics very abnormal, that represents the characteristics of continental crust contamination. On the basis of The main and trace elements, AFC and Hf-Nd isotopic characteristics of the evolution trend of multi evidence, we identified three samples with the characteristics of the initial magma may be directly derived from the mantle source region, Hf-Fe-Sr-Nd-Pb isotope composition (176Hf/177Hf=0.282962, 87Sr, /86Sr=0.705861143Nd/144Nd=0.512675206Pb/204Pb=18.305, 56Fe=0.13%, 207Pb/204Pb=15.642208Pb/204Pb=38.948) to represent the characteristics of China in southwestern Tengchong. Mantle source region through the simulation of melt "experiment, we think that the best model for the origin of Tengchong volcano can be expressed as: by metasomatism of the mantle source region (by the original 95-99% (DMM) and 1-5% depleted mantle subducted sediments (GLOSS) global composition) experienced partial melting of 1-4% after the formation of Tengchong primary magma. These have enriched mantle characteristics. The original magma may be derived from a subduction related metasomatic lithospheric mantle so, The enriched mantle end member of the mantle source region and the former Tengchong volcano rock proposed (such as EM1, EM2 or DUPAUL) have no direct contact with the mantle, they are similar. In addition to the isotopic characteristics of the mantle plume district is the lack of evidence, we speculate that the Tengchong volcano in the background is stretching and reverse stress on the subcontinent of India under the heat of the enriched continental lithospheric mantle upwelled triggered. Due to the metasomatic enriched mantle group prone to melting, Tengchong volcano rock is product divided after the decompression melting of continental lithospheric mantle enrichment group.

【學(xué)位授予單位】：中國(guó)科學(xué)技術(shù)大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2016
【分類號(hào)】：P597;P588.14
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本文編號(hào)：1437078