CAJ | 학술논문

通过对泾河流域深入的野外考察,在其中游基岩峡谷内发现了含有龙山文化末期文化层和古洪水滞流沉积单元的全新世黄土土壤剖面.利用光释光的单片测年技术,确定古洪水滞流沉积层覆盖着的黑垆土层的OSL年龄为 4078±382aB.P. 和 4111±450aB.P. .结合其中所含龙山文化遗址的考古年代,揭示出泾河流域在 4100～4000aB.P.之间出现一个古洪水多发时期.这组古洪水滞流沉积单元包含5个单层,记录了 4100～4000aB.P.之间泾河流域曾经发生的5次特大古洪水事件.这个洪水期对应着我国北方在4000aB.P.前后,由全新世大暖期向着全新世晚期干旱期转折过程中的气候剧烈变化.这些史前洪水事件可能对我国龙山文化的衰落和古代华夏文明的诞生具有重大的影响.
통과대경하류역심입적야외고찰,재기중유기암협곡내발현료함유룡산문화말기문화층화고홍수체류침적단원적전신세황토토양부면.이용광석광적단편측년기술,학정고홍수체류침적층복개착적흑로토층적OSL년령위 4078±382aB.P. 화 4111±450aB.P. .결합기중소함룡산문화유지적고고년대,게시출경하류역재 4100～4000aB.P.지간출현일개고홍수다발시기.저조고홍수체류침적단원포함5개단층,기록료 4100～4000aB.P.지간경하류역증경발생적5차특대고홍수사건.저개홍수기대응착아국북방재4000aB.P.전후,유전신세대난기향착전신세만기간한기전절과정중적기후극렬변화.저사사전홍수사건가능대아국룡산문화적쇠락화고대화하문명적탄생구유중대적영향.
In tributary valleys of the Yellow River over the Loess Plateau,it has been found that slackwater deposits due to past overbank floods were alternated with loess and soil formation throughout the Holocene. These bedded palaeoflood deposits without subsequent erosion and destruction recorded past hydrological events. Their age can be indirectly obtained by optically stimulated luminescence(OSL)dating of their intercalated loess and soil. During our fieldwork,such palaeoflood slackwater deposits were identified in a loess-soil sequence of the Jinghe River middle reaches. Loess and soil samples taken from this sequence were studied with polymineral fine grain OSL dating based on a single aliquot regenerative-dose(SAR)protocol. All OSL measurements were made using an automated Ris(φ) TL/OSL DA-15 system. The dose rate was converted with the concentration of U,Th and K in samples. The dating results show that the extreme palaeofloods occurred 4100～4000aB.P. ,that is,the late period of Longshan Culture(4300～4000aB.P.). This flood episode involved five flood depositional layers,indicating at the least five extreme flood events occurred on the Jinghe River. It can be seen at some of valley terraces that ruins of the Longshan Culture were inundated with these flood layers. The flooding episode corresponded to the climatic turn from the Middle Holocene Climatic Optimum to the Late Holocene dry-cold climate about 4200～4000aB.P.in North China. Because the climate conditions were highly instable and variable in this episode,those flood events may be of great importance to the collapse of the Neolithic Longshan Culture and the emergence of Chinese Bronze Civilization,especially the emergence of the Xia Dynasty.