哈尔滨黄土位于欧亚黄土带最东端,对揭示亚洲内陆干旱化东向扩展进程具有重要意义。早先的哈尔滨黄土堆积的底界年龄与亚洲干旱化进程相矛盾,这限制了对松嫩平原气候—地貌—构造—水系演化等耦合过程的理解。论文对哈尔滨荒山黄土剖面...哈尔滨黄土位于欧亚黄土带最东端,对揭示亚洲内陆干旱化东向扩展进程具有重要意义。早先的哈尔滨黄土堆积的底界年龄与亚洲干旱化进程相矛盾,这限制了对松嫩平原气候—地貌—构造—水系演化等耦合过程的理解。论文对哈尔滨荒山黄土剖面进行较高分辨率的14C、OSL和ESR测年,并通过实际测年结果拟合外推证实了所建立年代学框架的合理性,得出以下结论:①基于贝叶斯模型计算得出哈尔滨黄土底界年龄为170 ka;②哈尔滨黄土位于东亚季风气候区的北缘,代表了欧亚黄土带最东端的风尘堆积,哈尔滨黄土开始堆积指示其源区已发生明显干旱化,即松嫩沙地的形成不晚于170 ka BP,亚洲内陆干旱化的东移进程也因此得到进一步证实;③哈尔滨黄土堆积是对松嫩平原气候—构造(松辽分水岭隆升)—水系演化(松花江水系演化和松嫩古湖消亡)等的共同响应,因此,在可靠的年龄框架基础上哈尔滨黄土底界年龄对松辽分水岭的构造隆升和松花江水系演化的时间具有一定限制作用。展开更多
第四纪处于气候的快速波动期,黄土记录了丰富的古气候信息。为探讨汉江上游地区晚更新世以来气候变化过程,对汉江上游洋县境内汉江Ⅰ级河流阶地朱家村剖面沉积特征、常量元素分布、地球化学参数及形成时代进行研究。结果表明:汉江上游...第四纪处于气候的快速波动期,黄土记录了丰富的古气候信息。为探讨汉江上游地区晚更新世以来气候变化过程,对汉江上游洋县境内汉江Ⅰ级河流阶地朱家村剖面沉积特征、常量元素分布、地球化学参数及形成时代进行研究。结果表明:汉江上游Ⅰ级河流阶地形成于50 ka BP前后;剖面由下到上具有典型黄土(L_(1))→古土壤(S_(0))→全新世黄土(L_(0))→表层土(TS)的地层序列;剖面主要化学成分为SiO_(2)、Al_(2)O_(3)和Fe_(2)O_(3),化学风化过程中Ca、Na元素迁移淋失程度较高,K、Mg元素迁移淋失程度相对较低;剖面化学风化程度呈现从典型黄土(L_(1))→古土壤(S_(0))逐渐增强,到全新世黄土(L_(0))层又略降低的规律,记录了该区域气候在50~11 ka BP干燥寒冷,由11.00 ka BP开始逐渐增温增湿,2.50 ka BP到达最暖湿,2.50~0 ka BP持续降温变干的演变过程。研究成果可为我国北亚热带古气候重建提供数据参考。展开更多
The Zoige Basin,located in the eastern region of the Tibetan Plateau of China,is characterized by its climate sensitivity and complex surface environment.It is vital to understand the response of the surface processes...The Zoige Basin,located in the eastern region of the Tibetan Plateau of China,is characterized by its climate sensitivity and complex surface environment.It is vital to understand the response of the surface processes to environmental changes in the Zoige Basin since the last deglaciation,as well as the response of environmental changes and surface processes on the Tibetan Plateau relate to global changes.In August 2020,a field investigation was conducted in the Zoige Basin.A complete set of stratigraphic profile from the high platform at the front of the glacial-diluvial fan in the Maqu reach of the western basin was selected as the research subject.Optically stimulated luminescence(OSL)dating samples and sedimentary samples were collected from key layers and brought back to the laboratory for experimental analysis,and the surface processes and environment changes since the last deglaciation in the Zoige Basin were investigated through particle size analysis and OSL dating.The results showed that during the last glacial period before 14.5 kyr,a substantial glacial-alluvial fan composed of sand and gravel layers was formed by flash flood processes triggered by glacial meltwater and heavy precipitation.In the Bølling-Allerød warm period of 14.5–11.7 kyr,a warm and humid climate prevailed,with the formation of silty bog environments in the shallow depressions at the glacial-alluvial fan's forefront and the development of gray-green bog soil deposits.However,during the Younger Dryas period,an abrupt climate deterioration occurred,with the upper section of the gray-green bog soil layer in the shallow depression to experience folding and deformation due to surface freeze-thaw actions.During the early Holocene period from 11.7 kyr to 8.5 kyr,the climate was relatively dry,resulting in prevalent aeolian sand activitities.Coarse silt accumulated in the shallow depression,and sedimentary facies alternating between aeolian sand and bog soil deposits developed owing to strong wind patterns on the plateau surface.In the warm and humid period from 8.5 kyr to 3.1 kyr,increased weathering and pedogenesis enhanced clay content in sediments,which developed into the paleosol.In the late Holocene,starting from 3.1 kyr,the climate became relatively dry once more,with aeolian sand activity prevalent.The coarse silt that accumulated during the late Holocene transformed into subalpine meadow black soil because of rising temperature and humidity levels.These findings indicated that the developmental process of the high platform in the Maqu reach of the Zoige Basin,which was significant for understanding the environmental changes and surface processes in the source region of the Yellow River since the last deglaciation.展开更多
选取福建长乐典型海岸沙丘进行研究,在光释光（OSL）年代学基础上,结合环境代用指标分析和地质雷达图像,探讨研究区晚全新世以来沙丘发育历史及其古环境意义。结果显示：①东山（DS）沙丘发育过程主要存在5个沉积期和3个沉积间断。主要...选取福建长乐典型海岸沙丘进行研究,在光释光（OSL）年代学基础上,结合环境代用指标分析和地质雷达图像,探讨研究区晚全新世以来沙丘发育历史及其古环境意义。结果显示：①东山（DS）沙丘发育过程主要存在5个沉积期和3个沉积间断。主要反映了东亚季风强度变化,是东亚冬季风的区域响应结果。同时与火山活动、中国东部冬半年气温、夏季风降水具有良好对应关系;② DS剖面保存了近6 ka以来福州盆地海平面变化信息。清晰记录了存在于闽粤台地区的大范围的高海面期,分别是5.6～2.8 ka BP、2.8～1.7 ka BP、1.7～0.8 ka BP,其中1.7～0.8ka BP阶段最为明显。③ DS沙丘发育过程与闽东北区域人类活动记录以及新石器文化序列具有良好对应关系。5.6～2.8 ka BP、2.8～1.7 ka BP阶段的人类活动主要受到自然环境影响。～1.7ka BP之后,唐代至五代是福建社会经济的复苏阶段。展开更多
对郧县—白河段汉江Ⅰ级河流阶地上风成黄土的沉积学、理化性质、地球化学和年代学进行了系统研究.结果表明,汉江Ⅰ河流阶的形成不晚于25 ka BP;黄土具有马兰黄土（L1）→过渡黄土（L1）→古土壤（S0）→全新世黄土（L0）→表土（TS）...对郧县—白河段汉江Ⅰ级河流阶地上风成黄土的沉积学、理化性质、地球化学和年代学进行了系统研究.结果表明,汉江Ⅰ河流阶的形成不晚于25 ka BP;黄土具有马兰黄土（L1）→过渡黄土（L1）→古土壤（S0）→全新世黄土（L0）→表土（TS）的地层序列,与渭河谷地的黄土地层序列完全可比;25 ～ 11.5 kaBP,冬季风强盛,气候冷干,从11.5 ka BP开始,冬季风逐渐减弱,气候开始向暖湿方向逐步转化,从8.5 ka BP开始,夏季风达到了末次冰期结束后的鼎盛时期,3.1 ka BP前后,东亚季风格局发生变化,夏季风减弱,重新进入一个相对干冷的时期,而人类活动对地表的影响形成了表土;汉江上游谷地黄土记录的末次冰期后季风逐渐加强、中全新世季风强盛、随后季风衰退和气候变干的夏季风演变模式与渭河谷地黄土的记录高度一致,与邻区石笋和泥炭记录的季风变化趋势也有良好的可比性,但与石笋/泥炭记录的夏季风强盛期的起始时间（9.3 ～ 4.2 kaBP）并不完全一致.展开更多
在对汉江上游河谷进行野外考察的基础上,就郧县盆地汉江I级阶地及其风成黄土-古土壤覆盖层沉积学和理化性质进行了研究,并且采用OSL方法进行了测年断代。获得了26个OSL年龄数据,证实厚层风成黄土L1底部的年龄在25 ka BP,而剖面底部风成...在对汉江上游河谷进行野外考察的基础上,就郧县盆地汉江I级阶地及其风成黄土-古土壤覆盖层沉积学和理化性质进行了研究,并且采用OSL方法进行了测年断代。获得了26个OSL年龄数据,证实厚层风成黄土L1底部的年龄在25 ka BP,而剖面底部风成黄土-冲积砂层交互层(T1-al2)年龄范围在55-25 ka BP之间。地层年龄说明I级阶地上黄土的堆积过程基本连续,汉江I级阶地的发展经历了早期新构造抬升与河流下切阶段(55-25 ka BP)和晚期阶地面稳定接受沉积(25-0 ka BP)两个阶段。距今55 ka BP前后,新构造运动抬升和汉江下切作用加剧,河漫滩相沉积层开始脱离水面并接受风尘堆积物。这个过程持续到距今约25 ka BP,期间河水不时地淹没阶地面,从而形成了风成黄土-冲积砂交互的沉积学特征。距今约25 ka BP以来,河水不再淹没阶地,汉江I级阶地最终形成,阶地面开始接受连续的风尘堆积。在汉江下切作用加剧的同时,全球性末次冰期的发展也逐步进入冰盛期,风尘活动强烈,在阶地表面堆积形成了厚层黄土。汉江I级阶地形成以来,气候的变化使黄土覆盖层受到不同程度的风化成壤改造,形成了黄土-古土壤地层,其地层序列从下向上依次为:河流相砂卵石层(T1-al1)→黄土-冲积砂互层(T1-al2)→马兰黄土(L1)→过渡黄土(Lt)→古土壤(S0)→近代黄土(L0)→表土(MS)。这个层序记录汉江上游流域自从25 ka BP以来的气候变化经历末次冰期后东南季风逐渐加强、中全新世季风强盛、晚全新世季风衰退和气候变干的演变模式。展开更多
文摘哈尔滨黄土位于欧亚黄土带最东端,对揭示亚洲内陆干旱化东向扩展进程具有重要意义。早先的哈尔滨黄土堆积的底界年龄与亚洲干旱化进程相矛盾,这限制了对松嫩平原气候—地貌—构造—水系演化等耦合过程的理解。论文对哈尔滨荒山黄土剖面进行较高分辨率的14C、OSL和ESR测年,并通过实际测年结果拟合外推证实了所建立年代学框架的合理性,得出以下结论:①基于贝叶斯模型计算得出哈尔滨黄土底界年龄为170 ka;②哈尔滨黄土位于东亚季风气候区的北缘,代表了欧亚黄土带最东端的风尘堆积,哈尔滨黄土开始堆积指示其源区已发生明显干旱化,即松嫩沙地的形成不晚于170 ka BP,亚洲内陆干旱化的东移进程也因此得到进一步证实;③哈尔滨黄土堆积是对松嫩平原气候—构造(松辽分水岭隆升)—水系演化(松花江水系演化和松嫩古湖消亡)等的共同响应,因此,在可靠的年龄框架基础上哈尔滨黄土底界年龄对松辽分水岭的构造隆升和松花江水系演化的时间具有一定限制作用。
文摘第四纪处于气候的快速波动期,黄土记录了丰富的古气候信息。为探讨汉江上游地区晚更新世以来气候变化过程,对汉江上游洋县境内汉江Ⅰ级河流阶地朱家村剖面沉积特征、常量元素分布、地球化学参数及形成时代进行研究。结果表明:汉江上游Ⅰ级河流阶地形成于50 ka BP前后;剖面由下到上具有典型黄土(L_(1))→古土壤(S_(0))→全新世黄土(L_(0))→表层土(TS)的地层序列;剖面主要化学成分为SiO_(2)、Al_(2)O_(3)和Fe_(2)O_(3),化学风化过程中Ca、Na元素迁移淋失程度较高,K、Mg元素迁移淋失程度相对较低;剖面化学风化程度呈现从典型黄土(L_(1))→古土壤(S_(0))逐渐增强,到全新世黄土(L_(0))层又略降低的规律,记录了该区域气候在50~11 ka BP干燥寒冷,由11.00 ka BP开始逐渐增温增湿,2.50 ka BP到达最暖湿,2.50~0 ka BP持续降温变干的演变过程。研究成果可为我国北亚热带古气候重建提供数据参考。
基金Under the auspices of the National Natural Science Foundation of China(No.41971116,42271046,42277449)Fundamental Research Funds for the Central Universities(No.2020TS102)。
文摘The Zoige Basin,located in the eastern region of the Tibetan Plateau of China,is characterized by its climate sensitivity and complex surface environment.It is vital to understand the response of the surface processes to environmental changes in the Zoige Basin since the last deglaciation,as well as the response of environmental changes and surface processes on the Tibetan Plateau relate to global changes.In August 2020,a field investigation was conducted in the Zoige Basin.A complete set of stratigraphic profile from the high platform at the front of the glacial-diluvial fan in the Maqu reach of the western basin was selected as the research subject.Optically stimulated luminescence(OSL)dating samples and sedimentary samples were collected from key layers and brought back to the laboratory for experimental analysis,and the surface processes and environment changes since the last deglaciation in the Zoige Basin were investigated through particle size analysis and OSL dating.The results showed that during the last glacial period before 14.5 kyr,a substantial glacial-alluvial fan composed of sand and gravel layers was formed by flash flood processes triggered by glacial meltwater and heavy precipitation.In the Bølling-Allerød warm period of 14.5–11.7 kyr,a warm and humid climate prevailed,with the formation of silty bog environments in the shallow depressions at the glacial-alluvial fan's forefront and the development of gray-green bog soil deposits.However,during the Younger Dryas period,an abrupt climate deterioration occurred,with the upper section of the gray-green bog soil layer in the shallow depression to experience folding and deformation due to surface freeze-thaw actions.During the early Holocene period from 11.7 kyr to 8.5 kyr,the climate was relatively dry,resulting in prevalent aeolian sand activitities.Coarse silt accumulated in the shallow depression,and sedimentary facies alternating between aeolian sand and bog soil deposits developed owing to strong wind patterns on the plateau surface.In the warm and humid period from 8.5 kyr to 3.1 kyr,increased weathering and pedogenesis enhanced clay content in sediments,which developed into the paleosol.In the late Holocene,starting from 3.1 kyr,the climate became relatively dry once more,with aeolian sand activity prevalent.The coarse silt that accumulated during the late Holocene transformed into subalpine meadow black soil because of rising temperature and humidity levels.These findings indicated that the developmental process of the high platform in the Maqu reach of the Zoige Basin,which was significant for understanding the environmental changes and surface processes in the source region of the Yellow River since the last deglaciation.
文摘选取福建长乐典型海岸沙丘进行研究,在光释光（OSL）年代学基础上,结合环境代用指标分析和地质雷达图像,探讨研究区晚全新世以来沙丘发育历史及其古环境意义。结果显示：①东山（DS）沙丘发育过程主要存在5个沉积期和3个沉积间断。主要反映了东亚季风强度变化,是东亚冬季风的区域响应结果。同时与火山活动、中国东部冬半年气温、夏季风降水具有良好对应关系;② DS剖面保存了近6 ka以来福州盆地海平面变化信息。清晰记录了存在于闽粤台地区的大范围的高海面期,分别是5.6～2.8 ka BP、2.8～1.7 ka BP、1.7～0.8 ka BP,其中1.7～0.8ka BP阶段最为明显。③ DS沙丘发育过程与闽东北区域人类活动记录以及新石器文化序列具有良好对应关系。5.6～2.8 ka BP、2.8～1.7 ka BP阶段的人类活动主要受到自然环境影响。～1.7ka BP之后,唐代至五代是福建社会经济的复苏阶段。
文摘对郧县—白河段汉江Ⅰ级河流阶地上风成黄土的沉积学、理化性质、地球化学和年代学进行了系统研究.结果表明,汉江Ⅰ河流阶的形成不晚于25 ka BP;黄土具有马兰黄土（L1）→过渡黄土（L1）→古土壤（S0）→全新世黄土（L0）→表土（TS）的地层序列,与渭河谷地的黄土地层序列完全可比;25 ～ 11.5 kaBP,冬季风强盛,气候冷干,从11.5 ka BP开始,冬季风逐渐减弱,气候开始向暖湿方向逐步转化,从8.5 ka BP开始,夏季风达到了末次冰期结束后的鼎盛时期,3.1 ka BP前后,东亚季风格局发生变化,夏季风减弱,重新进入一个相对干冷的时期,而人类活动对地表的影响形成了表土;汉江上游谷地黄土记录的末次冰期后季风逐渐加强、中全新世季风强盛、随后季风衰退和气候变干的夏季风演变模式与渭河谷地黄土的记录高度一致,与邻区石笋和泥炭记录的季风变化趋势也有良好的可比性,但与石笋/泥炭记录的夏季风强盛期的起始时间（9.3 ～ 4.2 kaBP）并不完全一致.
文摘在对汉江上游河谷进行野外考察的基础上,就郧县盆地汉江I级阶地及其风成黄土-古土壤覆盖层沉积学和理化性质进行了研究,并且采用OSL方法进行了测年断代。获得了26个OSL年龄数据,证实厚层风成黄土L1底部的年龄在25 ka BP,而剖面底部风成黄土-冲积砂层交互层(T1-al2)年龄范围在55-25 ka BP之间。地层年龄说明I级阶地上黄土的堆积过程基本连续,汉江I级阶地的发展经历了早期新构造抬升与河流下切阶段(55-25 ka BP)和晚期阶地面稳定接受沉积(25-0 ka BP)两个阶段。距今55 ka BP前后,新构造运动抬升和汉江下切作用加剧,河漫滩相沉积层开始脱离水面并接受风尘堆积物。这个过程持续到距今约25 ka BP,期间河水不时地淹没阶地面,从而形成了风成黄土-冲积砂交互的沉积学特征。距今约25 ka BP以来,河水不再淹没阶地,汉江I级阶地最终形成,阶地面开始接受连续的风尘堆积。在汉江下切作用加剧的同时,全球性末次冰期的发展也逐步进入冰盛期,风尘活动强烈,在阶地表面堆积形成了厚层黄土。汉江I级阶地形成以来,气候的变化使黄土覆盖层受到不同程度的风化成壤改造,形成了黄土-古土壤地层,其地层序列从下向上依次为:河流相砂卵石层(T1-al1)→黄土-冲积砂互层(T1-al2)→马兰黄土(L1)→过渡黄土(Lt)→古土壤(S0)→近代黄土(L0)→表土(MS)。这个层序记录汉江上游流域自从25 ka BP以来的气候变化经历末次冰期后东南季风逐渐加强、中全新世季风强盛、晚全新世季风衰退和气候变干的演变模式。
