HIGH RESOLUTION CYCLESTRATIGRAPHY BASED ON DARK ANDLITGT COLOR-BANDED CLAYLAYERS

odp leg127从日本海海盆遗址恢复的晚第四纪沉积物具有明显的深色和浅色带状粘土的特征。暗层和亮层的厚度从1厘米到2米多不等。这些暗层和亮层是相关的，并且是同步的盆地宽度，表明它们记录了某种区域性或全球性的古环境变化，而日本海作为一个单一的系统做出了反应。为了了解这些暗层和亮层的含义，我们分析了晚第四纪样品。在海平面高潮期，日本海表水的高盐度使得深水生产和海底通风更加密集，因此对马暖流通过对马海峡的流入非常显著。中期林分期，东海沿岸海水向对马海峡入海口传播并入海。由于海水盐度较低，沿岸水的流入造成了较弱的密度分层和较低的深水产量，造成了缺氧至缺氧的底水状态。在极低潮期，日本海几乎被隔离，表层海水盐度急剧下降，造成强烈的密度分层，形成稳定的低氧底水状态。对明暗层的高分辨率分析表明，由地球轨道元素引起的米兰科维奇旋回以及格陵兰冰芯报告的丹斯加德-奥斯格振荡记录在日本海沉积物中，表现为有机碳含量的变化、硅藻丰度的变化和碎屑组分中科沙组分的变化。在中间林分期间，浅海环流对海平面变化最为敏感。

LATE QUATERNARY SEDIMENTS RECOVERED BY THE ODP LEG127 FROM THE BASINAL SITES OF THE JAPAN SEA ARE CHARACTERIZED WITH DISTINCTLY DARK AND LIGHT COLOR-BANDED CLAY.THICKNESS OF THE DARK AND LIGNT LAYERS VARIES FROM A CENTIMETER TO MORE THAN 2 METERS.THESE DARK AND LIGHT LAYERS ARE CORRELATABLE AND SYNCHRONOUS BASIN WIDE,SUGGESTING THEY RECORD SOME SORT OF REGIONAL OR GLOBAL PALEOENVIRONMENTAL CHANGES TO WHICH THE JAPAN SEA RESPONDED AS A SINGLE SYSTEM.IN ORDER TO UNDERSTAND THE IMPLICATION OF THESE DARK AND LIGNT LAYERS,WE ANALYZED LATE QUATERNARY SAMPLES.INFLOW OF THE TSUSIMA WARM CURRENT THROUGH THE TSUSIMA STRAIT WAS SIGNIFICANT DURING SEA LEVEL HIGHSTANDS WHEN HIGH SALINITY OF THE SURFACE WATER OF THE JAPAN SEA ALLOWED INTENSIVE DEEP WATER PRODUCTION AND VENTILATION OF THE BOTTOM.DURING INTERMEDIATE STANDS,THE EAST CHINA SEA COASTAL WATER PROPAGATED TO THE MOUTH OF THE TSUSIMA STRAIT AND FLOWED INTO THE SEA.DUE TO ITS LOWER SALINITY,THE INFLOW OF THE COASTAL WATER CAUSED WEAK DENSITY STRATIFICATION AND SUBDUED PRODUCTION OF DEEP WATER,WHICH RESULTED IN ANOXIC TO EUXINIC BOTTOM WATER CONDITION.DURING THE VERY LOWSTANDS,THE JAPAN SEA WAS NEARLY ISOLATED AND THE SURFACE WATER SALINITY DRASTICALLY DECREASED,CAUSING STRONG DENSITY STRATIFICATION,WHICH RESULTED IN STABLE EUXINIC BOTTOM WATER CONDITION.HIGH RESOLUTION ANALYSES OF THE DARK AND LIGHT LAYERS SUGGESTED THAT MILANKOVICH CYCLE RESULTING FROM THE EARTHS ORBITAL ELEMENTS AS WELL AS DANSGAARD-OESCHGER OSCILLATION REPORTED FROM GREENLAND ICE CORES ARE RECORDED IN THE JAPAN SEA SEDIMENTS AS VARIATION IN ORGANIC CARBON CONTENT,DIATOM ABUNDANCE CHANGES,AND CHANGES IN KOSA FRACTION WITHIN DETRITAL COMPONENT.IT WAS ALSO SUGGESTED THAT PALE-OCEAN CIRCULATION HAS BEEN MOST SENSITIVE TO SEA LEVEL CHANGES DURING INTERMEDIATE STANDS.