發(fā)布時(shí)間：2018-06-27 07:02

  本文選題：佳木斯地塊 + 新元古代-早古生代�。� 參考：《吉林大學(xué)》2017年博士論文

【摘要】：本文對(duì)佳木斯地塊林口-勃利地區(qū)和密山地區(qū)麻山雜巖中表殼巖及侵入其內(nèi)的正片麻巖和各類侵入巖,進(jìn)行了巖石學(xué)、鋯石LA-ICP-MS和SIMS U-Pb年代學(xué)、全巖地球化學(xué)及鋯石Hf同位素的綜合研究,證實(shí)了新元古代巖漿作用的存在、并查明其期次、組合及巖石成因,限定了麻粒巖相變質(zhì)作用的峰期-退變質(zhì)時(shí)間及麻山雜巖中表殼巖的沉積時(shí)限,分析了早古生代巖漿作用的成因機(jī)制及其與晚泛非期高級(jí)變質(zhì)作用的關(guān)系,探討了佳木斯地塊與東岡瓦那大陸Kuunga造山帶的親緣性關(guān)系,初步對(duì)佳木斯地塊可能的時(shí)空演化進(jìn)行了嘗試性恢復(fù)。密山地區(qū)和林口-勃利地區(qū)正片麻巖的原巖結(jié)晶年齡分別為898~891Ma和757~751Ma,首次明確指示佳木斯地塊上至少存在兩期新元古代巖漿作用。~895Ma巖漿作用的產(chǎn)物主要為正長(zhǎng)花崗巖,具有高硅、高鉀、過(guò)鋁、低Sr/Y的特征,鋯石εHf(t)值為-4.2~+0.9(主體為負(fù)值),表明其巖漿起源于古老地殼(成熟度可能較高)的部分熔融,在巖漿演化過(guò)程中存在新生地殼圍巖的混染作用;該期正長(zhǎng)花崗巖形成于俯沖相關(guān)的擠壓-拉張的過(guò)渡環(huán)境,最可能為Rodinia大陸邊緣增生階段的產(chǎn)物。~752Ma巖漿作用主要形成一套堿長(zhǎng)花崗巖、正長(zhǎng)花崗巖和二長(zhǎng)花崗巖的組合,其具有類A型花崗巖的地球化學(xué)特征,鋯石飽和溫度介于788~845℃,鋯石εHf(t)值為-2.8~+4.5(主體為正值),且主、微量元素與SiO2之間具有明顯的線性變化關(guān)系,表明其主要來(lái)源于相對(duì)低壓環(huán)境下的新生地殼物質(zhì)的部分熔融,并伴有虧損軟流圈地幔的熱量和物質(zhì)的雙重貢獻(xiàn),在巖漿演化過(guò)程中經(jīng)歷了分離結(jié)晶作用和古老地殼圍巖的混染作用;該期花崗巖屬于高分異i型花崗巖,其與興凱地塊~757ma變玄武巖構(gòu)成雙峰式火成巖組合,最可能形成于rodinia裂解機(jī)制下的伸展背景。密山地區(qū)麻山雜巖中副片麻巖的碎屑鋯石年齡介于2548~1064ma,結(jié)合~895ma正片麻巖侵入其內(nèi)的地質(zhì)事實(shí),表明麻山雜巖中表殼巖的原巖沉積時(shí)限為1064~898ma。此外,新元古代正、副片麻巖中記錄的諧和變質(zhì)年齡介于568~476ma,綜合考慮鋯石成因類型和野外實(shí)際觀察,可以將其分成兩組:其一為569~560ma(~563ma),測(cè)自固態(tài)重結(jié)晶、重置的變質(zhì)鋯石,且其同位素體系基本未遭受后期熱事件的擾動(dòng),代表了麻粒巖相變質(zhì)作用的峰期時(shí)間;其二為546~476ma,測(cè)自固相線生長(zhǎng)、亞固相線生長(zhǎng)、溶解-再沉淀、重組、重置的變質(zhì)鋯石,其最可能形成于鋯石不同程度蛻晶化或后期富流體花崗巖侵位階段,表明該組年齡反映的是退變質(zhì)作用的時(shí)間。在麻粒巖相變質(zhì)作用峰期之后,佳木斯地塊發(fā)生了大規(guī)模的早古生代巖漿作用,活動(dòng)時(shí)間為541~476ma(持續(xù)~65ma)。該期巖漿作用的產(chǎn)物包括~500ma輝長(zhǎng)巖、~515ma石英正長(zhǎng)巖和541~476ma花崗閃長(zhǎng)巖-二長(zhǎng)花崗巖-正長(zhǎng)花崗巖。~500ma輝長(zhǎng)巖起源于受俯沖流體交代的富集巖石圈地幔的部分熔融,在巖漿演化過(guò)程中基本未受到陸殼物質(zhì)的混染。541~476ma各類花崗質(zhì)巖石(包括~515ma石英正長(zhǎng)巖)屬于普通i型或高分異i型花崗巖,具有復(fù)雜的地球化學(xué)特征,揭示其來(lái)源于多個(gè)巖漿源區(qū),包括古老地殼物質(zhì)、新生地殼物質(zhì)及虧損地幔。i型花崗質(zhì)巖漿主要起源于相對(duì)低壓環(huán)境下地殼物質(zhì)的部分熔融,在巖漿形成及演化過(guò)程中伴隨著虧損地幔巖漿的加入,并遭受了圍巖物質(zhì)的同化混染作用。巖石組合、地球化學(xué)特征及麻粒巖相變質(zhì)作用p-t軌跡的綜合分析表明,佳木斯地塊541~476ma侵入巖形成于后造山的伸展環(huán)境,可能與近等溫減壓變質(zhì)階段后的晚泛非期造山帶的垮塌過(guò)程密切相關(guān)。佳木斯地塊和興凱地塊在新元古代-早白堊世(755~115ma)期間經(jīng)歷了相似的巖漿-變質(zhì)活動(dòng),表明它們?cè)诘刭|(zhì)演化過(guò)程中屬于同一陸塊整體,而中生代敦化-密山斷裂不能作為兩者之間的構(gòu)造界線。綜合上述研究成果、已發(fā)表的區(qū)域地質(zhì)資料及全球范圍內(nèi)的系統(tǒng)對(duì)比,認(rèn)為佳木斯-興凱地塊屬于中亞造山帶中的外來(lái)地體,其不太可能直接來(lái)源于西伯利亞、華北或華南克拉通,而與西伯利亞南緣Sayang-Baikal造山帶和東岡瓦那Kuunga造山帶具有不同程度的可比性。鑒于在新元古代巖漿巖的構(gòu)造背景、早古生代變質(zhì)-巖漿作用過(guò)程、表殼巖年齡特征及物源組成等方面,佳木斯-興凱地塊與東南極和西澳大利亞更為相似,本文提出在晚泛非期時(shí)佳木斯-興凱地塊最可能為Kuunga造山帶的一部分,在1000~750Ma期間,其與東南極-澳大利亞一起記錄了Rodinia聚合-裂解的演化;而在570~470Ma期間,其又經(jīng)歷了Kuunga造山帶從碰撞造山至后造山垮塌的全部過(guò)程;之后在470~433Ma的某個(gè)時(shí)間,佳木斯-興凱地塊從東岡瓦那裂解出來(lái)、并向北漂移,直至210~185Ma才在太平洋作用下與與松遼地塊完成碰撞拼合,最終就位于中亞造山帶東緣。
[Abstract]:In this paper, the lithology, zircon LA-ICP-MS and SIMS U-Pb geochronology, all rock geochemistry and zircon Hf isotopes have been carried out in the Mashan complex of the Jiamusi massif and the Boli and Mishan areas, which have been intruded into the orthopes and various intrusive rocks, which confirmed the existence of the Neoproterozoic magmatism and ascertained its period. The genetic mechanism of the early Palaeozoic magmatism and the relationship with the late Pan African Advanced metamorphism are analyzed, and the relationship between the Jiamusi block and the Kuunga orogenic belt of the East Gondwana continent is discussed. The possible temporal and spatial evolution of the Jiamusi massif was tentatively restored. The original rock age of the primary rock in the Mishan region and the Linkou Boli region was 898~891Ma and 757~751Ma, respectively. It was the first time that there was at least two Neoproterozoic magmatism on the Jiamusi massif. The main product of the ~895Ma magmatism was the long granite. Rock, characterized by high silicon, high potassium, over aluminum, and low Sr/Y, the zircon epsilon Hf (T) value is -4.2~+0.9 (the main body is negative), indicating that the magma originated from the partial melting of the ancient crust (the maturity may be higher), and in the process of magma evolution there was a mixed staining of the surrounding rock of the new crust in the process of magma evolution, and this period of granites was formed by subduction related squeezing and stretching. To ferry the environment, the most likely product of the Rodinia continental margin, the product of.~752Ma magmatism, mainly formed a set of alkali feldspar, the combination of the zigzah granite and two granites, which had the geochemical characteristics of the type A type granite, and the zircon saturation temperature was at 788~845 C, and the value of the zircon epsilon Hf (T) was -2.8~+4.5 (the main body was positive), and the main and trace amounts were trace. There is a clear linear relationship between the element and the SiO2, which indicates that it mainly originates from the partial melting of the new crust material in the relative low pressure environment and the dual contribution of the heat and substance of the mantle of the loss asthenosphere. In the process of magma evolution, the separation and crystallization of the crust is mixed with the ancient crustal surrounding rock, and this period of granite is a granite. The rock belongs to the high Division I type granite, which is composed of the Shuangfeng type igneous rock composed of the ~757ma basalt of Xingkai massif, most likely to be formed in the extension background under the mechanism of Rodinia cracking. The detrital zircon age of the parisnee in the Mishan area of the Mashan complex is between 2548~1064ma and the geological facts of the intrusion of ~895ma gneiss, indicating that Mashan The Proterozoic sedimentary rocks in the complex rocks are limited to 1064~898ma., in Neoproterozoic, and in the consonant metamorphic age recorded in parnegneiss, which can be divided into two groups: one is 569~560ma (~563ma), a solid recrystallization, a resetting metamorphic zircon, and its isotopes. The system basically does not suffer from the disturbance of late thermal events and represents the peak time of granulite facies metamorphism, and the second is 546~476ma, which is measured from solid phase line growth, subsolid phase line growth, dissolving reprecipitation, reorganizing and resetting metamorphic zircon, which is most likely to be formed in the phase of metamorphic crystallization of zircon or in the emplacement stage of late rich fluid granite. The age of the group reflects the time of retrograde metamorphism. After the peak period of the granulite facies metamorphism, a large-scale Early Paleozoic magmatism occurred in the Jiamusi massif, and the activity time was 541~476ma (continuous ~65ma). The products of the magmatism included ~500ma gabbro, ~515ma quartz syenite and 541~476ma granodiorite - two granitic granite. The.~500ma gabbro of the zigzah granite originated from partial melting of the enriched lithospheric mantle under subduction fluid. During the evolution of the magma, the mixture of.541~476ma granitic rocks (including ~515ma quartz syenite), which was not contaminated by the crust material, belonged to the common I or high fractionated I type granites, which had complex geochemical characteristics. It is revealed that it originates from several magmatic source areas, including ancient crustal matter, new crust material and.I type granitic magma of the depleted mantle derived mainly from partial melting of crustal material under the relative low pressure environment, which is accompanied by the addition of the depleted mantle of magma in the process of magma formation and evolution, and has been subjected to assimilation and contamination of rock mass. The comprehensive analysis of rock assemblage, geochemical characteristics and P-T trajectories of granulite facies metamorphism shows that the 541~476ma intrusive rocks in the Jiamusi massif are formed in the extensional environment of the post orogenic belt, which may be closely related to the collapse process of the late pan non phase orogenic belt after the nearly isothermal decompression and metamorphism stage. The Jiamusi and Xingkai blocks are in the Neoproterozoic Early Cretaceous. During the period of 755~115ma, similar magmatic metamorphism has been experienced, indicating that they belong to the same monolithic whole in the process of geological evolution, while the Mesozoic Dunhua Mishan fault can not be used as a tectonic boundary between the two. The results of the study, the published regional geological data and the system comparison in the global scope, are considered to be Jiamusi Xing. The Kay massif belongs to the Central Asian orogenic belt, which is not likely to be directly derived from Siberia, North China or Southern China craton, but with the Sayang-Baikal orogenic belt of the southern margin of Siberia and the East gonzwana Kuunga orogenic belt in varying degrees. The Jiamusi Xingkai block is more similar to the southeast pole and Western Australia in the process, the age characteristics of the crust rock and the source composition of the Jiamusi Xingkai block. This paper suggests that the Jiamusi Xingkai massif is most likely to be part of the orogenic belt in the late Pan African period. In the period of 1000~750Ma, it recorded the Rodinia polymerization cracking together with the southeast pole Australia. In the period of 570~470Ma, the whole process of the evolution of the Kuunga orogenic belt from the collision orogenic to the post orogeny; then, at some time in the 470~433Ma, the Jiamusi Xingkai block broke out from the East Gondwana and moved northward until the 210~185Ma was used to complete the collision with the Songliao block in the Pacific Ocean. The eastern margin of the Central Asian orogenic belt.
【學(xué)位授予單位】：吉林大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2017
【分類號(hào)】：P542
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本文編號(hào)：2073086