陳于高臺灣大學：地質科學研究所巫姿萱Wu, Tzu-ShuanTzu-ShuanWu2007-11-262018-06-282007-11-262018-06-282007http://ntur.lib.ntu.edu.tw//handle/246246/54861螢光法的定年技術近年來持續發展之下，已經可以廣泛的應用於各種不同的地質標本；如容易完全曬退的標本像是風成環境以及濱海相的沉積物；亦或部分曬退的沉積物像是河相環境的沉積物，因此，各種沉積物的埋藏年代的測定，可以應用於各種研究目的，來解決古氣候、古地震，以及考古學方面的問題。 在台灣，地震會造成許多嚴重的山崩，這些未固結的土石容易伴隨颱風及豪雨，一瀉而下形成土石流。這些快速堆積的土石常在河階沖積層中被發現，通常由大小不等的礫石及卵石組成，其中以粗砂為基質。而河階的形成年代常是台灣用以研究新構造活動的一個主要材料。在台灣具有山高水急的特性，所以一般河流沉積物的搬運距離短，土石流之堆積更加快速，見光曬退的機率則成為應用螢光定年於土石流沉積物時的主要考量。 研究中選擇了兩個中台灣的土石流發生地區做螢光法的測試分析：(1) 於陳有蘭溪中游的白不仔溪河口採集四個標本 (分別為夾雜在礫石間的基質砂樣；沙層中的砂樣；退水時期所堆積的外洗砂及一般河道搬運之河道砂) (2) 在九九峰地區的乾溪採集三個標本 (分別為夾雜在礫石間的基質砂樣；，另剖面頂部在退水時期所堆積的外洗砂以及一般河道搬運之河道砂)。 本研究希望用最有效率的方法找到曬退最好的標本，所以傳統最有效率的單片法以及新的單顆粒法，都被用於測試沈積剖面上，不同位置所採之樣本。結果顯示最適合處理現生土石流沉積物的方法，是使用單顆粒法去逼近。另外，河道外洗砂的殘餘訊號小於土石流剖面上的其他標本。經過了上面的測試，我們得知像土石流沉積物這樣搬運距離短的標本，一樣有機會被曬退。當然是愈是年輕的標本，較長的搬運距離愈是可以增加被曬退的機會，當然也會增加螢光定年法的可信度。Continuous technological development in luminescence dating techniques has facilitated extensive application to a variety of geologic samples, such as completely bleached sediments from aeolian and shoreface environments or even partially bleached sediments from fluvial environments. Using the luminescence method, the burial ages of sediments last exposed to daylight can be determined, and applied to research areas in paleoclimatology, paleoseismology and archaeology. In Taiwan, earthquakes trigger numerous and serious landslides, the source of disastrous debris flow while heavy rainfalls and typhoons generate unconsolidated landslide material. The rapidly deposited sediments are often found within fluvial terraces, composed of boulders, cobbles and pebbles embedded with sandy matrix. To study the neotectonic activity, knowledge of the burial ages of fluvial terraces is essential. Due to the short transported distance, probable exposure to daylight bleaching is the major concern in the reliability of the luminescence dating of such a deposit. Two individual sites of modern debris deposits in central Taiwan are selected for the luminescence analysis: (1) 4 samples (one from matrix, one from sandy layer, one from outwash sand and one from channel deposits) were collected in the middle reach of one of the tributaries of Chenyulan River. (2) 3 samples (one each from matrix, fluvial sandy bar and outwash channel deposits) were collected near the Ninety-Nine Peak. Regeneration Protocol was adopted as the routine procedure. In finding the most efficient way, both single aliquot and single grain methods were applied to extract the well bleaching portion from debris deposits. Sediments from different debris facies are separately determined. Our results reveal that the single grain approach provides best way to deal with those debris materials. In addition, the residual signals were smaller in the outwash samples than the matrix of the debris flow itself. It can be concluded that even a short distance could still give enough light to bleach certain parts of debris sediments. The longer transportation distance of the fluvial deposits facilitates the bleaching and increases the reliability of the luminescence dating method, especially for the young material.Table of Content Page List of Figures.........................................vii List of Tables...........................................ix 摘要 (Chinese Abstract) ..................................x Abstract.................................................xi Chapter 1 Introduction....................................1 1.1 Motivation............................................1 1.2 Optically Stimulated Luminescence Dating..............2 1.3 Debris Flow...........................................4 1.3.1 Definition..........................................4 1.3.2 Origin of Debris Flow...............................5 1.3.3 Sedimentary Facies..................................7 Chapter 2 Optical Dating Method...........................9 2.1 Basic Principles......................................9 2.1.1 Luminescence........................................9 2.1.2 Energy Band Model of Luminescence..................10 2.2 Sample Preparation...................................12 2.3 Age Estimation.......................................13 2.3.1 Paleodose..........................................13 2.3.1.1 Single-Aliquot and Single Grain Regeneration (SAR) Protocol.................................................14 2.3.2 Annual Dose........................................17 2.4 Other Basic Luminescence Properties..................18 2.5 Statistical Methods to Compute Paleodose............ 19 Chapter 3 Geological Background of Study Area............21 3.1 Chenyulan River (CYL series).........................22 3.1.1 Field Observation of CYL Series....................23 3.2 Ninety-Nine Peak (NNP Series)........................24 3.2.1 Field Observation of NNP Series....................25 Chapter 4 Result.........................................27 4.1 Luminescence Properties Examination..................27 4.1.1 Preheat Plateau....................................27 4.1.2 Growth Curve.......................................28 4.1.3 Thermal Transfer...................................28 4.1.4 Dose Recovery Test.................................29 4.1.5 Calibration of Dose Rate...........................30 4.2 Single Aliquot Result................................31 4.3 Single Grain Result..................................35 4.4 Modern Fluvial Deposit...............................37 Chapter 5 Discussion.....................................38 5.1 Debris Flow Motion Behavior and the OSL Signal.......38 5.2 Discuss of Results of CYL and NNP Series Samples.....39 5.3 The Feasibility of Single Grain Protocol on Modern Debris Deposit...........................................43 5.4 Uncertainty of the Age Determination.................45 Chapter 6 Conclusion.....................................47 Reference................................................482102027 bytesapplication/pdfen-US現生土石流沉積物光螢光部分曬退單顆粒法moderndebris sedimentsOSLpartial bleachingsingle grainthesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/54861/1/ntu-96-R94224109-1.pdf