本文選題：超大陸重建　切入點(diǎn)：全球磁異常網(wǎng)格數(shù)據(jù)集　出處：《中國(guó)地質(zhì)大學(xué)(北京)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：超大陸的聚合、增生與裂解是地球演化過程中的重大地質(zhì)事件,對(duì)地球各圈層都有著極其重要的影響。超大陸重建主要根據(jù)各陸塊邊界的吻合,陸塊之間古氣候、古生物、地層、構(gòu)造、巖漿等資料和古地磁學(xué)數(shù)據(jù),而利用磁測(cè)數(shù)據(jù)研究板塊之間的相互關(guān)系比較少。大陸磁異常包含了豐富的大地構(gòu)造信息,特別是在深部構(gòu)造解釋方面,磁異常資料有重要優(yōu)勢(shì)。2009年發(fā)布的全球磁異常網(wǎng)格數(shù)據(jù)集是從衛(wèi)星磁測(cè)、航空磁測(cè)、海洋磁測(cè)、地磁臺(tái)地面觀測(cè)和人工地磁勘測(cè)得到的數(shù)據(jù)匯編而成,為研究地球深部構(gòu)造、巖石圈形態(tài)特征以及地球動(dòng)力學(xué)問題提供了大量科學(xué)數(shù)據(jù)和證據(jù)。本文將大陸磁異常的特征和解釋應(yīng)用于超大陸的重建,以檢驗(yàn)現(xiàn)有的主要基于地質(zhì)資料和古地磁資料提出的各板塊之間連接的合理性。同時(shí),在超大陸重建的框架下,也有利于我們進(jìn)一步了解古老穩(wěn)定的克拉通結(jié)晶基底可能引起中、長(zhǎng)波長(zhǎng)的磁異常特征。本文在Gplates軟件中將全球磁異常網(wǎng)格數(shù)據(jù)集繪制成全球磁異常圖,分析得出大洋磁異常特征和大陸磁異常特征明顯不同,大陸磁異常的幅度普遍大于大洋磁異常的幅度。本文分析了大洋磁異常特征,認(rèn)為大洋磁異常特征有三種類型,即大洋磁異常條帶、洋島磁異常和“消失的大陸”造成的磁異常。本文分析了大陸磁異常特征,認(rèn)為大陸磁異常可以分出兩種類型,即造山帶磁異常和克拉通磁異常。造山帶磁異常波長(zhǎng)一般較短,而克拉通磁異常波長(zhǎng)一般較長(zhǎng),造山帶和克拉通磁異常特征明顯不同,界線明顯,可以據(jù)此劃分出大地構(gòu)造單元。本文在Gplates軟件中重建了 1590Ma時(shí)期的Nuna超大陸、900Ma時(shí)期的Rodinia超大陸和230 Ma時(shí)期的Pangea超大陸,以及Pangea超大陸中的Gondwana古陸。將磁異常數(shù)據(jù)疊加到對(duì)應(yīng)的陸塊(構(gòu)造單元)之上,可以看出各陸塊之間磁異常的連接關(guān)系反映出古老的結(jié)晶基底在超大陸時(shí)期連接在一起,而造山帶之間磁異常的連接性也體現(xiàn)出同一時(shí)期的造山事件而使造山帶具有相似的磁性分布。本文重點(diǎn)分析了 Laurentia、Greenland、Baltica和Siberia磁異常特征,將磁異常信息重建了 1590Ma時(shí)期它們之間的連接,這些克拉通磁異常的連接性比較好,說明1590Ma時(shí)期Nuna核心模型比較合理。
[Abstract]:Supercontinent aggregation, proliferation and fragmentation are major geological events in the course of the Earth's evolution, and have an extremely important impact on the Earth's various circles. The reconstruction of the supercontinent is mainly based on the matching of the boundaries of the continents, paleoclimate and paleontology between the landmasses. Stratigraphic, tectonic and magmatic data and paleomagnetic data, while the use of magnetic data to study the correlation between plates is relatively rare. The continental magnetic anomalies contain abundant tectonic information, especially in the interpretation of deep structures. The global magnetic anomaly grid data set released in 2009 was compiled from satellite magnetic survey, aeromagnetic survey, marine magnetic survey, geomagnetic station ground observation and artificial geomagnetic survey to study the deep structure of the earth. In this paper, the characteristics and interpretation of the continental magnetic anomalies are applied to the reconstruction of the supercontinent. To test the reasonableness of existing connections between plates based primarily on geological and paleomagnetic data. At the same time, in the framework of supercontinent reconstruction, It is also helpful for us to further understand the characteristics of medium and long wavelength magnetic anomalies caused by the ancient stable craton crystalline substrates. In this paper, the global magnetic anomaly grid data set is mapped into a global magnetic anomaly map in Gplates software. It is concluded that the characteristics of oceanic magnetic anomaly are obviously different from those of continental magnetic anomaly, and the amplitude of continental magnetic anomaly is generally larger than that of oceanic magnetic anomaly. In this paper, the characteristics of oceanic magnetic anomaly are analyzed, and it is considered that there are three types of oceanic magnetic anomaly. In this paper, the characteristics of continental magnetic anomalies are analyzed, and it is concluded that there are two types of continental magnetic anomalies, such as oceanic magnetic anomalies, oceanic island magnetic anomalies and "vanishing continents". The magnetic anomaly wavelength of orogenic belt is shorter than that of cratonic magnetic anomaly, while the wavelength of cratonic magnetic anomaly is longer, the characteristics of orogenic belt and cratonic magnetic anomaly are obviously different and the boundary is obvious. The authors have reconstructed the Nuna supercontinent of 1590 Ma and the Rodinia supercontinent of 900 Ma and the Pangea supercontinent of 230 Ma in the Gplates software. And the Gondwana paleocontinent in the Pangea supercontinent. When the magnetic anomaly data are superimposed on the corresponding continental blocks (tectonic units), it can be seen that the connection of the magnetic anomalies among the blocks reflects that the ancient crystalline basement was connected together during the supercontinental period. The connectivity of the magnetic anomalies between the orogenic belts also reflects the orogenic events of the same period and makes the orogenic belts have similar magnetic distribution. This paper focuses on the analysis of the magnetic anomalies of Laurentia Greenland Baltica and Siberia. The magnetic anomaly information was reconstructed and the connection between them was reconstructed at 1590 Ma. The connectivity of these cratonic magnetic anomalies is good, which indicates that the core model of Nuna in 1590 Ma is reasonable.
【學(xué)位授予單位】：中國(guó)地質(zhì)大學(xué)(北京)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：P318;P541

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