發(fā)布時間：2018-01-10 17:29

  本文關(guān)鍵詞：27Ka以來日本海北部的沉積記錄與環(huán)境響應　出處：《中國海洋大學》2014年碩士論文　論文類型：學位論文

  更多相關(guān)文章： 日本海 敏感組分 磁化率 化學元素相對含量 環(huán)境響應

【摘要】：邊緣海既是連接大洋跟陸地之間的紐帶和橋梁，又是與陸地進行物質(zhì)能量交換的主要地區(qū)，其對大陸的氣候演變具有顯著的影響。日本海作為西北太平洋最大和最典型的半封閉邊緣海，重建其沉積記錄對于認識日本海本身、太平洋乃至全球的氣候演化和海平面波動具有重要的意義，同時對分析其與東亞各區(qū)域氣候系統(tǒng)及環(huán)境特征之間的關(guān)系，了解東亞古環(huán)境在特殊氣候事件和關(guān)鍵地質(zhì)時期的演變，以及預測今后可能發(fā)生的氣候變化及環(huán)境演化趨勢，都具有參考的價值。 本文選擇位于日本海北部深層水環(huán)流通道上的巖芯作為研究對象，綜合沉積物粒度參數(shù)、環(huán)境磁學、化學元素相對含量及顏色反射率等指標，通過與相關(guān)文獻及資料對比分析，對其沉積地層進行劃分，分析該區(qū)域的沉積環(huán)境演化歷史。結(jié)果顯示，沉積物以粉砂粒級為主，含量大多超過了60%，砂的含量和粘土的含量都相對較少，但是由于沉積年代跨度較大，且經(jīng)歷了較多的冷暖氣候突變，，因此顆粒大小在垂向上浮動變化較大，通過粒度分析結(jié)果得到敏感組分（22.1-420.4μm）的平均粒徑和含量來做為日本海北部研究區(qū)域沉積環(huán)境的替代指標，結(jié)合開樣記錄和現(xiàn)場觀測，將柱狀樣初步分為八層。通過對磁化率各向異性參數(shù)的分析，整個沉積過程保持了較為原始的沉積狀態(tài)，自形成后并未受到明顯的擾動影響。通過樣品磁化率的垂向變化趨勢發(fā)現(xiàn)，與粗顆粒（砂）含量變化的相關(guān)性更好，基本表現(xiàn)出樣品的顆粒越粗，磁化率值越大的特征，此外結(jié)合顏色反射率數(shù)據(jù)，推測粗顆粒沉積物中的深色鐵磁性礦物是造成沉積物磁化率改變的關(guān)鍵因素。通過Ti元素相對含量的變化曲線可以得出沉積過程中陸源物質(zhì)的輸入變化。Fe元素相對含量可以與粒度參數(shù)、磁化率參數(shù)、顏色反射率成良好的相關(guān)關(guān)系。Co、Zn等過渡金屬元素的相對含量可以初步的反映沉積環(huán)境中的含氧量及氧化還原條件。Ca、Sr元素相對含量則可以作為非陸源沉積的標志，從而間接的推斷出沉積環(huán)境的氧化還原條件和水動力強度。對巖芯的96cm處和346cm處進行的AMS14C測年結(jié)果顯示，兩處的沉積年代分別為8910±25a.BP和26900±90a.BP。 通過對柱狀樣沉積記錄的分析，結(jié)合已有的資料，初步推斷在末次冰期以來發(fā)生的全球性冷暖氣候突變事件在日本海北部有所響應，對研究區(qū)的沉積環(huán)境進行初步的反演，得到以下的結(jié)果： 巖芯346cm深度處從距今約27000年開始沉積，整個沉積過程可能分別經(jīng)過了D-O事件——H2事件（24.1Ka BP的Heinrich事件）——D-O事件——末次盛冰期——D-O事件——H1事件（16.8Ka BP的Heinrich事件）——波令-阿勒羅德暖期——新仙女木事件——8Ka BP冷事件——全新世大暖期。
[Abstract]:The edge of the sea is the connecting bridge between the ocean with the land, and is the main area of the exchange of material and energy and land, the continental climate change has a significant impact. The sea of Japan as the Pacific Northwest largest and most typical semi enclosed marginal sea, the sedimentary record of reconstruction for the understanding of the sea of Japan itself, has an important the significance of climate change and sea level fluctuations in the Pacific and the world, and the analysis of its relationship with the East Asian regional climate system and environmental characteristics, understand the evolution of the East Asian ancient environment in special climate events and key geological period, and predict the possibility of future climate change and environmental evolution tendency, has the reference value.
This choice is located in the Japan sea deep water circulation channel on the core as the research object, comprehensive sediment parameters, environmental magnetism, chemical elements and relative content of color reflectance index, and through the analysis of relevant literature and data comparison, classify their sedimentary strata, sedimentary environment in the region of evolutionary history. The results showed that the sediment the main content of silt, mostly more than 60%, the content of sand and clay are relatively small, but because the depositional age of large span, and experienced more cold climate change, so the particle size in the vertical floating vary by the particle size analysis results of sensitive components (22.1-420.4 m). The average particle size and content as a substitute index of Japan north of the study area the sedimentary environment, based on the sample records and field observation, the columnar sample was divided into eight layers. The analysis of the anisotropy of magnetic susceptibility parameters, the deposition process keeps the deposition state more primitive, since after the formation has not been disturbed obviously. Discoveries to the trend of the magnetic susceptibility in the vertical, and coarse particles (sand) better correlation between the content changes of the samples showed more coarse particles of magnetization the rate of eigenvalue is larger, in addition to combine color reflectance data and that of coarse sediment in dark ferromagnetic minerals is a key factor to cause the change of magnetic susceptibility of sediments. The change curve of Ti content can be obtained by.Fe element input changes terrigenous deposition process with the relative content of grain size parameters, magnetic susceptibility parameters and a good correlation between the color reflectance.Co, sedimentary environment can reflect the initial relative content of Zn transition metal elements in oxygen and redox conditions.Ca, S The relative content of R element can be used as a marker for non terrigenous sediments, thereby indirectly infer the oxidation of sedimentary environment and hydrodynamic conditions to restore strength. 96cm and 346cm of the core of the AMS14C dating results show that in the two deposition were 8910 + 25a.BP and 26900 + 90a.BP.
Through the analysis of the sedimentary record of columnar samples, combined with the existing data, concluded that in the event of global changes since the last glacial climate change events respond in Japan Sea and preliminary inversion sedimentary environment in the study area, we obtain the following results:
The core at the depth of 346cm from about 27000 years ago began to deposition, the deposition process may be respectively after the D-O H2 event (24.1Ka BP event, Heinrich event, D-O event) - LGM - D-O - H1 events (16.8Ka event BP Heinrich event) - wave to Al Rhodes, the Younger Dryas warm period the event 8Ka BP cold event - Holocene warm period.

【學位授予單位】：中國海洋大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：P736.2

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相關(guān)期刊論文 前10條

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本文編號：1406173