本文選題：內(nèi)蒙古喇嘛音烏蘇 + 晚更新世�。� 參考：《中國地質(zhì)大學(xué)(北京)》2015年碩士論文

【摘要】：內(nèi)蒙古錫林郭勒盟地區(qū)分布有大面積北西-南東向分布的新生代火山巖區(qū),與蒙古共和國東南部的達(dá)里干加新生代火山巖相連,為亞洲最大的新生代板內(nèi)玄武巖,作者在前人研究的基礎(chǔ)上對(duì)內(nèi)蒙古錫林浩特喇嘛音烏蘇地區(qū)新生代火山巖進(jìn)行調(diào)查研究,查明了火山機(jī)構(gòu)類型、火山巖相及火山噴發(fā)時(shí)代等,劃分了火山噴發(fā)期次,研究了巖石地球化學(xué)特征及大地構(gòu)造環(huán)境,取得了有意義的成果和認(rèn)識(shí)。通過野外調(diào)查與綜合研究,將晚更新世火山作用劃分為四個(gè)噴發(fā)亞旋回,且每個(gè)噴發(fā)亞旋回可進(jìn)一步劃分2個(gè)以上數(shù)量不一的噴發(fā)韻律。劃分出五種主要巖相類型包括噴溢相、火山爆發(fā)崩塌相、火山噴發(fā)沉積相、涌流相及火山通道相,包括錐狀、盾狀、瑪珥式火山。火山作用產(chǎn)物分布特征是火山口附近主要有玄武質(zhì)集塊巖、浮巖、含火山彈火山角礫巖、玄武質(zhì)凝灰角礫巖、致密塊狀橄欖玄武巖、氣孔狀橄欖玄武巖,形成火山機(jī)構(gòu)主體,遠(yuǎn)離火山口主要是橄欖玄武巖漿溢流的熔巖流,構(gòu)成熔巖臺(tái)地,產(chǎn)狀平緩,局部球形風(fēng)化。玄武巖中常見有幔源橄欖石、輝石及下地殼斜長石捕擄晶,少量的花崗巖捕擄體。通過地球化學(xué)分析表明,玄武巖中Ti、Y等呈“V”形,虧損；Ba、Nb、La等呈峰狀,富集,總體反映強(qiáng)不相容元素富集。稀土元素總量(ΣREE)均值為214.50×10-6,輕重稀土比(LREE/HREE)值在2.05-4.56之間,δ Eu在0.94-1.13之間,異常不明顯,CeN/YbN的值在4.99-13.20之間,屬于輕稀土富集型。新生代玄武巖形成于板塊邊緣拉張環(huán)境下,板內(nèi)裂谷型玄武巖,并且與地幔柱活動(dòng)有關(guān)。通過火山噴發(fā)沉積相中獲得光釋光(osl)年齡為116.4±5.6Ka和123.2±5.5Ka,進(jìn)一步厘定了內(nèi)蒙古錫林浩特喇嘛音烏蘇地區(qū)新生代火山作用時(shí)代為晚更新世,為該地域該期火山作用的年代學(xué)研究提供了重要的依據(jù)。
[Abstract]:There is a large area of Cenozoic volcanic rocks in the Xilingulmeng area of Inner Mongolia, which is connected with the Dariganga Cenozoic volcanic rocks in the southeast of Mongolia, and is the largest Cenozoic intraplate basalt in Asia. On the basis of previous studies, the author investigates and studies the Cenozoic volcanic rocks in the Lama-yinwusu area, Xilinhaote, Inner Mongolia, and finds out the types of volcanic institutions, volcanic facies and volcanic eruption epoch, and divides the volcanic eruption periods. The characteristics of geochemistry and geotectonic environment are studied, and significant results and understanding are obtained. Through field investigation and comprehensive study, the late Pleistocene volcanism is divided into four eruptive subcycles, and each eruption subcycle can be further divided into more than two different eruptive rhythms. There are five main lithofacies types, including ejection facies, volcanic eruption collapse facies, volcanic eruption sedimentary facies, inrush facies and volcanic channel facies, including conical, shield and Maar volcanoes. The distribution characteristics of volcanic products are that there are mainly Black Tortoise mass rocks, pumice rocks, volcanic breccia, Black Tortoise tuff breccia, dense block olivine basalt and stomatal olivine basalt near the crater, which form the main body of volcanic mechanism. Far away from the crater is mainly the lava flow overflowing by olivary Black Tortoise magma, which forms a lava platform with a gentle occurrence and local spherical weathering. Mantle-derived olivine pyroxene and lower crust plagioclase are common in basalt and a small amount of granites. Through geochemical analysis, it is shown that Tiao Y is "V" shape in basalt, and Bajiu Nbni-La in depleted basalt is peak and enriched, which reflects the enrichment of strongly incompatible elements in general. The mean value of total rare earth element (危 REE) is 214.50 脳 10 ~ (-6), the LREE / HREE value is 2.05-4.56, 未 EU is 0.94-1.13, and the abnormal CeN- / YbN value is between 4.99-13.20, which belongs to the light rare earth enrichment type. The Cenozoic basalts were formed in the extensional environment of the plate margin, and the intraplate rift basalts are related to mantle plume activity. The age of photoluminescence in sedimentary facies of volcanic eruption is 116.4 鹵5.6Ka and 123.2 鹵5.5 Ka. it is further determined that the Cenozoic volcanic epoch in Xilinhaote, Inner Mongolia, is the late Pleistocene. It provides an important basis for the chronological study of volcanism in this region.
【學(xué)位授予單位】：中國地質(zhì)大學(xué)(北京)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：P588.14;P317

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相關(guān)期刊論文 前1條

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本文編號(hào)：1930527