{"created":"2023-06-20T13:21:19.824204+00:00","id":1498,"links":{},"metadata":{"_buckets":{"deposit":"33ccccae-5c00-4c3e-935a-178585817811"},"_deposit":{"created_by":21,"id":"1498","owners":[21],"pid":{"revision_id":0,"type":"depid","value":"1498"},"status":"published"},"_oai":{"id":"oai:ir.soken.ac.jp:00001498","sets":["2:429:18"]},"author_link":["0","0","0"],"item_1_creator_2":{"attribute_name":"著者名","attribute_type":"creator","attribute_value_mlt":[{"creatorNames":[{"creatorName":"杉崎, 彩子"}],"nameIdentifiers":[{}]}]},"item_1_creator_3":{"attribute_name":"フリガナ","attribute_type":"creator","attribute_value_mlt":[{"creatorNames":[{"creatorName":"スギサキ, サイコ"}],"nameIdentifiers":[{}]}]},"item_1_date_granted_11":{"attribute_name":"学位授与年月日","attribute_value_mlt":[{"subitem_dategranted":"2009-09-30"}]},"item_1_degree_grantor_5":{"attribute_name":"学位授与機関","attribute_value_mlt":[{"subitem_degreegrantor":[{"subitem_degreegrantor_name":"総合研究大学院大学"}]}]},"item_1_degree_name_6":{"attribute_name":"学位名","attribute_value_mlt":[{"subitem_degreename":"博士（理学）"}]},"item_1_description_12":{"attribute_name":"要旨","attribute_value_mlt":[{"subitem_description":"　　Marine sediments contain important archives of past ocean and climate changes,<br />but at high latitudes, such as the polar regions, the absence of carbonate has prevented<br />the construction of accurate chronological models. To get an age model, a method<br />which does not rely on carbonate is needed. In this thesis we have investigated the<br />potential of optically stimulated luminescence (OSL) dating to establish a chronology<br />for our deep sea sediment cores from the Northern Pacific area. OSL dating makes use<br />of the omnipresent quartz and feldspar grains in the sediment so there is no limitation<br />in the presence of the dosimeter. Optical dating is a widely accepted dating method for<br />terrestrial sediments, but only few studies have tested its reliability in the marine<br />environment.<br />　A luminescence age reflects the time that has elapsed since the sediment grains were<br />last exposed to sunlight. The luminescence age equation contains two equally<br />important factors: the equivalent dose and dose rate. The equivalent dose is the total<br />radiation dose that crystals (quartz, feldspar) have absorbed during burial, and the dose<br />rate is the rate at which the sample was exposed to ionising radiation in the<br />environment. Dividing the equivalent dose by the dose rate gives the luminescence age<br />of the sample.<br />　This study is focused on testing the reliability of the optical dating method when<br />applied to marine sediments from the Northern Pacific ocean, more specifically in<br />regions that are known for seasonal-sea ice. The aims of this thesis are (1) determine<br />the accuracy of luminescence ages, e.g. by comparison with AMS <sup>14</sup>C dating and<br />marine oxygen isotope stratigraphy where possible, (2) produce a high resolution<br />sequence of absolute ages which can describe changes in sedimentation rate through<br />time, and (3) test whether it is possible to date back to marine isotope stage 5e (MIS<br />5e).<br />　In this thesis we have made use of fine (4- 11 μm) grains of quartz extracted from the<br />marine sediment cores taken in the south-western Sea of Okhotsk, the Bering Sea and<br />the Central Sea of Okhotsk. In the first study, a high resolution optical age dataset (64<br />samples) from the south-western Sea of.Okhotsk showed continuous ages up to 24 ka<br />and indicated clear sedimentation rate differences during glacial and interglacial<br />periods. Also for the most northern located core in the Bering Sea (sub-arctic area), the<br />OSL ages (12 samples) could date to 64ka and the ages are in good agreement with the<br /><sup>14</sup>Cage ～25ka. The OSL ages in this study are in good agreement with the <sup>14</sup>C ages.<br />In the third study in the central Sea of Okhotsk, a test of accuracy of the OSL ages<br />back to MIS 5e was carried out. The OSL ages (40 samples) are in good agreement<br />with the well-established oxygen isotope stratigraphy at this site back to the MIS 5e<br />(130ka). In all these studies, the luminescence characteristics of the dosimeter are<br />investigated in detail and extensive tests of the performance in the chosen<br />measurement protocol are presented.<br />　Despite the good agreement of the optical ages with the independent age control, it<br />must be noted that the OSL ages are largely dependent on the water content. The<br />evaluation of the appropriate water content model is discussed. It appears that the<br />observed water content values, measured immediately after core extraction, seem to<br />give the most accurate ages.<br />　This thesis shows that OSL dating is a useful method for dating marine sediment in<br />the North Pacific area. The data confirm that the OSL dating using fine-grain quartz<br />that is distributed all over the ocean has very great potential in the establishment of an<br />absolute chronology for deep sea sediments; because luminescence does not depend on the presence of carbonate for AMS <sup>14</sup>C dating, it is now likely that we can establish a<br />chronology is regions of the ocean that were previously undatable.","subitem_description_type":"Other"}]},"item_1_description_7":{"attribute_name":"学位記番号","attribute_value_mlt":[{"subitem_description":"総研大甲第1283号","subitem_description_type":"Other"}]},"item_1_select_14":{"attribute_name":"所蔵","attribute_value_mlt":[{"subitem_select_item":"有"}]},"item_1_select_8":{"attribute_name":"研究科","attribute_value_mlt":[{"subitem_select_item":"複合科学研究科"}]},"item_1_select_9":{"attribute_name":"専攻","attribute_value_mlt":[{"subitem_select_item":"16 極域科学専攻"}]},"item_1_text_10":{"attribute_name":"学位授与年度","attribute_value_mlt":[{"subitem_text_value":"2009"}]},"item_creator":{"attribute_name":"著者","attribute_type":"creator","attribute_value_mlt":[{"creatorNames":[{"creatorName":"SUGISAKI, Saiko","creatorNameLang":"en"}],"nameIdentifiers":[{}]}]},"item_files":{"attribute_name":"ファイル情報","attribute_type":"file","attribute_value_mlt":[{"accessrole":"open_date","date":[{"dateType":"Available","dateValue":"2016-02-17"}],"displaytype":"simple","filename":"甲1283_要旨.pdf","filesize":[{"value":"311.9 kB"}],"format":"application/pdf","licensetype":"license_11","mimetype":"application/pdf","url":{"label":"要旨・審査要旨","url":"https://ir.soken.ac.jp/record/1498/files/甲1283_要旨.pdf"},"version_id":"091b6327-dbf2-49b5-a805-9e3106051122"}]},"item_language":{"attribute_name":"言語","attribute_value_mlt":[{"subitem_language":"eng"}]},"item_resource_type":{"attribute_name":"資源タイプ","attribute_value_mlt":[{"resourcetype":"thesis","resourceuri":"http://purl.org/coar/resource_type/c_46ec"}]},"item_title":"High-resolution optical dating for marine sediments from North Pacific Ocean","item_titles":{"attribute_name":"タイトル","attribute_value_mlt":[{"subitem_title":"High-resolution optical dating for marine sediments from North Pacific Ocean"},{"subitem_title":"High-resolution optical dating for marine sediments from North Pacific Ocean","subitem_title_language":"en"}]},"item_type_id":"1","owner":"21","path":["18"],"pubdate":{"attribute_name":"公開日","attribute_value":"2010-06-09"},"publish_date":"2010-06-09","publish_status":"0","recid":"1498","relation_version_is_last":true,"title":["High-resolution optical dating for marine sediments from North Pacific Ocean"],"weko_creator_id":"21","weko_shared_id":-1},"updated":"2023-06-20T15:58:37.324206+00:00"}