【摘要】：長江三角洲地區(qū)的磁性地層認識存在很大不確定性.為建立一個可靠的年代標尺,為區(qū)內(nèi)沉積環(huán)境和氣候演化研究提供約束,在年代地層和磁性地層基礎(chǔ)上,以頻率磁化率為信號源、ETP為靶曲線,通過軌道調(diào)諧方法對區(qū)內(nèi)LZK1孔開展了天文年代標尺研究,建立了年代序列框架.結(jié)果顯示,M/B界線埋深約為143.0m、Ga/M界線埋深約為219.0m、Gi/Ga界線埋深約為296.6m.受氣候和沉積環(huán)境控制,沉積旋回特征清楚,沉積速率具有明顯的階段性.調(diào)諧后的頻率磁化率顯示了顯著的125ka、96ka、41ka、23ka、22ka、18ka等軌道周期,并在軌道周期上與ETP曲線高度相關(guān),相關(guān)性超過了95%檢驗標準.100ka、41ka和23ka周期的帶通濾波曲線與偏心率、斜率和歲差在振幅和相位上吻合較好,但局部時間段有差異,可能與低沉積速率、沉積速率突變或短時間尺度的地層缺失等因素有關(guān).研究表明,在具有短暫沉積缺失的持續(xù)沉降區(qū)域,只要保證樣品分辨率,可以通過軌道調(diào)諧方法建立可靠的年代框架.
[Abstract]:There is great uncertainty in the understanding of magnetic strata in the Yangtze River Delta region. In order to establish a reliable chronological scale and provide constraints for the study of sedimentary environment and climate evolution in the region, based on chronostratigraphy and magnetic strata, frequency susceptibility is used as signal source and ETP as target curve. The astronomical chronological scale of LZK1 holes in the region was studied by orbital tuning method, and the chronological sequence framework was established. The results show that the buried depth of the M / B boundary is about 143.0 m / m and the depth of the Ga / Ga line is about 219.0mGi / Ga boundary is about 296.6m. Controlled by climate and sedimentary environment, the characteristics of sedimentary cycle are clear, and the deposition rate has obvious stages. The frequency magnetization after tuning shows a remarkable orbital period of 125ka / 96ka / 41ka/ 23ka/ 22ka/ 18ka, and is highly correlated with the ETP curve in the orbital period, which exceeds the 95% test standard. The bandpass filtering curve and eccentricity of the 100ka / 41ka and 23ka period are obtained. The slope and precession agree well with each other in amplitude and phase, but there are differences in local time periods, which may be related to the low deposition rate, the sudden change of deposition rate or the lack of strata on a short time scale. It is shown that in the area of continuous subsidence with transient sedimentary absence, a reliable chronological framework can be established by orbital tuning method as long as the resolution of the sample is ensured.
【作者單位】： 中國地質(zhì)大學(xué)地球科學(xué)學(xué)院;上海市地質(zhì)調(diào)查研究院;中國科學(xué)院地球環(huán)境研究所;江蘇省地質(zhì)調(diào)查研究院;
【基金】：基金項目:長江三角洲海岸帶綜合地質(zhì)調(diào)查與監(jiān)測(No.GZH201200506) 上海區(qū)域地質(zhì)調(diào)查片區(qū)總結(jié)與服務(wù)產(chǎn)品開發(fā)(No.DD20160345-07)
【分類號】：P539.3
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本文編號：2291135