1：860万中国海区及邻域地貌图：板块构造地貌分类例析

本文论述了新近出版的１：８６０万《中国海区及邻域地貌图》采用的板块构造地貌分类的总体思路及分类方案。     

中国热带气候地貌几个问题的讨论

中国热带气候长期热湿,气候地貌的基本特征表现为强烈风化和持续剥蚀夷平,缺乏地貌的世代演替,所谓"双重风化"和"双重夷平"的经典概念,未必切合中国热带的实际情况.中国热带第四纪气候波动不明显,但是这种波动在气候地貌上仍有反映.红土砾石台地代表中更新世冷湿(砾石堆积)转热干(红土化)的气候地貌.老红砂台地代表晚更新世至全新世热干(风积)转热湿(红土化、古土壤)的气候地貌.海岸贝壳堤反映中全新世风暴潮增强的气候波动.广东、海南的所谓"冰臼群"实乃河流地貌的瓯穴.中国热带末次冰期的冰川遗迹仅见于台湾岛中央山脉.     

中国热带珊瑚礁的第四纪气候记录

珊瑚礁剖面的氧碳同位素、地球化学、造礁珊瑚生长带等分析结果表明,珊瑚礁记录了第四纪气候波动的基本轮廓.早更新世总体趋暖,但至少有4个旋回.中更新世总体趋冷,但至少有7个旋回.晚更新世气候剧烈波动,但总体变化为两个前暖后冷的旋回.全新世为回暖-升温-降温的波动.历史时期约1 700 a来有4个前冷后暖的旋回.近200 a的气候波动表现为前百年正距平,后百年以负距平为主,但总体趋暖.     

中国热带第四纪板块运动的地貌效应

The eastern and western fronts of plate movement in Taiwan Island and Tibetan Plateau respectively are the two major sources of tectonic force for the morphogensis during Quaternary in China′s tropics. Seven examples of geomorphological effects of plate movement are enumerated to discuss the differentiation of tectonic landforms in space and time during Quaternary. The tectonic movement tends to be more active since middle Pleistocene. Some phenomena such as the arc-shape mountain systems, volcanism and crustal deformation imply that the juncture zone of eastern and western tectonic forces is located at about 1 1O°E.     

中国热带第四纪气候波动特征

中国热带早更新世气候波动以高频率小幅度为特征。“中更新世革命”发生在MIS20／MIS21之交。中更新世气候波动一般为三大旋回。晚更新世为两大旋回,但有变暖事件D／01～21及变冷事件H1～H6的表现。可以识别末次间冰期MISS及其阶段5a～5e。末次亚间冰期有4～7次冷暖波动。末次冰期温度一般比今低1～2℃或3～5℃。终止点Ⅰ为15000～13670aB．P．。终止点Ⅱ为0．135～0．130MaB．P．。新冰期Ⅰ、Ⅱ、Ⅲ都有表现。历史时期出现南北朝冷期、北宋冷期、明清小冰期。近200a的气候,前百年升温,后百年降温。     

中国热带第四纪动物群与气候波动

中国热带第四纪动物群的70多个实例约有40%出现在冷期,反映气候波动幅度较小.动物群的时空分布可以佐证早更新世气候波动的2个主旋回、中更新世的3个主旋回、晚更新世的2个主旋回和全新世大暖期.末次冰期和新冰期未曾危及热带动物群的生存.历史时期的冷波动使动物逐步南迁,但其绝迹主要是受人为因素影响.     

中国热带第四纪气候波动幅度问题

根据40多个有关气候波动的实例分析,中国热带第四纪几个特征时段比今升温的幅度为1.0～3.0℃：降温幅度较大者为3．0～7．0℃,较小者为1．0—3．0℃。而中国热带地区现代理论雪线高度约为4300m;北半球长年冻土地带南界的年均温为-6．0～-8．0℃。因此,中国热带除台湾岛外,第四纪不具备形成冰川或冰缘现象的气候条件。     

中国热带第四纪气候波动的海陆对比

古气候分析典型实例的对比．表明中国热带第四纪的气候波动，海域与陆域的差异主要出现在早、中更新世及末次盛冰期，而晚更新世以来直至历史时期，海陆的气候波动基本同步。中国热带万年尺度的气候变化．既受地球轨道参数的驱动，亦受季风环流的影响；千年和百年尺度的气候变化，与太阳常数本身的变化有关。     

第四纪中国热带对全球气候变化的响应

根据20多个有关沉积、δ18O、孢粉、石笋等分析实例,并与代表全球变化的气候曲线进行对比,认为中国热带万年尺度气候变化的机制,早更新世为轨道驱动,中更新世为季风环流的非轨道驱动,晚更新世为轨道驱动,这个过程与青藏高原隆起的高度和速率有关.晚更新世的千年尺度变化和小冰期的百年尺度变化,其机制是受太阳常数周期性变化的影响.     

中国热带晚第四纪冷波动的地带性探讨

分析孢粉、氧碳同位素、硅藻、沉积、史籍记载等约70个实例,表明中国热带末次冰期晚期(MIS2)以来有12期主要的冷波动。冷波动的地区分布具有热带南部和北部的纬度地带性,冷波动分布和降温程度的经度地带性表现在西区、中区、东区、台湾岛4个区的分异。西区位于热带西部,属南亚季风区,冷波动少,降温幅度小;中区、东区、台湾岛位于热带东部,属东亚季风区,冬季风的强度有东西向的交替变化,中区的冷波动最明显。各期冷波动的降温幅度大多为0.5~2℃,少数为3~5℃。     

Geomorphological effects of plate movement during Quaternary in China'' s tropics

China'stropicsliesintheregionsouthofabout24oN,occupyinganareaofabout51.85×104km2(5.4%ofChina).InChina,thistropicalregionisquiteclosetotheeasternandwesternconvergentboundariesbetweentwoplatessothatthegeomorphologicaleffectsofplatetectonicsaremoreobviousthanthoseinnorthernChina.Thisstudywillpresentsevenexamplesofappearanceofplatemovementingeomorphology.1ThesourceoftectonicforceTheregionofChina'stropicsundergoesconvergingattackfromeasternandwestern"fronts"ofplatemovement.Thewesternfrontofther…     

Geomorphological effects of plate movemen during Quaternary in China＇s tropics

The eastern and western fronts of plate movement in Taiwan Island and Tibetan Plateau respectively are the two major sources of tectonic force for the morphogensis during Quaternary in China’s tropics. Seven examples of geomorphological effects of plate movement are enumerated to discuss the differentiation of tectonic landforms in space and time during Quaternary. The tectonic movement tends to be more active since middle Pleistocene. Some phenomena such as the arc-shape mountain systems, volcanism and crustal deformation imply that the juncture zone of eastern and western tectonic forces is located at about 110°E.     

Geomorphological effects of plate movement during Quaternary in China’s tropics

The eastern and western fronts of plate movement in Taiwan Island and Tibetan Plateau respectively are the two major sources of tectonic force for the morphogensis during Quaternary in China’s tropics. Seven examples of geomorphological effects of plate movement are enumerated to discuss the differentiation of tectonic landforms in space and time during Quaternary. The tectonic movement tends to be more active since middle Pleistocene. Some phenomena such as the arc-shape mountain systems, volcanism and crustal deformation imply that the juncture zone of eastern and western tectonic forces is located at about 110oE.     

阿尔泰山喀纳斯河谷晚第四纪冰川地貌演化过程

阿尔泰山喀纳斯河流域在第四纪期间发生过多次冰川进退,丰富的侵蚀与堆积地貌为区域地貌演化过程分析提供了重要依据,同时,该区的第四纪冰川作用对全球环境变化研究具有重要的科学意义。通过对喀纳斯湖口以下主谷内古冰川地貌的实地考察,测定不同地段多级U型谷底(台地)的海拔高度以及冰川漂砾的上限与分布位置,并对主谷内不同地段不同期次的冰碛物进行电子自旋共振(ESR)测年,研究发生在主谷内的古冰川作用系列、规模及演化过程。结果表明:喀纳斯湖到驼颈湾地区的谷地中主要发生过4次冰川作用,时代分别对应中梁贛冰期(MIS12)、MIS8/10、倒数第二次冰期(MIS6)以及末次冰期。末次冰期冰川作用又可细分为3个阶段,分别对应MIS4、MIS3中期与MIS2;根据三级U型谷的分布特征推断,古冰川作用规模呈现渐次变小的规律,自冰川站至下游接近冰川末端,中梁贛冰期时冰川厚度达50~395 m,覆盖范围包括主谷及两侧的山梁和支谷,延伸的长度和宽度都最大,MIS8/10以及倒二冰期时的厚度分别在102~199 m和88~269 m之间,冰川末端到达驼颈湾附近;鸭泽湖附近坡地上保存完好的多级台地,说明发生在河谷内的古冰川活性大,流动性和连续性较强,具有温冰川的性质;喀纳斯主谷有明显的不对称性,与局部小气候和地形对冰川的发育影响有关。     

中国热带琼雷生态经济区的建设构想

生态经济区克服了传统经济区生态环境约束下的经济增长瓶颈,是区域经济发展的重要内容和方向。目前黄河三角洲高效生态经济区和鄱阳湖生态经济区的建设都已引起国家的高度关注。琼雷生态经济区是在充分考虑了湛江市(雷州半岛)和海南省(海南岛)地区热带资源禀赋、生态环境脆弱性及经济空间紧密性的基础上提出来的战略构想。琼雷地区生态本底较好;热带作物资源、海洋资源及港口资源十分丰富,热带特色显著;经济结构以一、三产业为主,生态恢复与维护成本较小;存在地缘一致性和经济紧密性,有一定区域联系基础。但同时本区域存在生态环境的脆弱性,影响区域生态安全的因素较多,因此必须坚持生态主导下的经济发展原则。为此,建立中国热带琼雷生态经济区是必要的和及时的。本文从宏观的角度,详细分析了琼雷生态经济区的功能定位和建设的主要内容,以期在中国的典型热带区域打造生态经济区发展平台,构筑中国热带生态经济发展高地。     

Geomorphological and sedimentological features in Quaternary fluvial systems affected by solution-induced subsidence (Ebro Basin, NE-Spain)

The Quaternary evolution and the morpho-sedimentary features of some of the most important rivers in Spain (Ebro and Tagus rivers among others) have been controlled by subsidence due to alluvial karstification of the evaporitic bedrock. The subsidence mechanism may range from catastrophic collapse to slow sagging of the alluvium by passive bending. In the Ebro Basin, the mechanisms and processes involved in karstic subsidence were studied through the analysis of present-day closed depressions as well as through old subsidence depressions (palaeocollapses and solution-induced basins) and associated deformations recorded in the Quaternary alluvial sediments. The Gállego–Ebro river system is presented as a case study of channel adjustments and geomorphic and sedimentary evolution of fluvial systems in dissolution-induced subsidence areas. In this fluvial system, evaporite dissolution during particular Quaternary time intervals (namely early and middle Pleistocene) have lead to the development of a solution-induced basin, approximately 30 km-long by 8 km-wide, filled by Quaternary deposits with a total thickness in excess of 190 m. The main river response to balance the subsidence in the alluvial plain was aggradation in the central reach of the subsiding area, and degradation both in the upstream reach and in the valley sides where alluvial fans and covered pediments may prograde over the fluvial sediments. The main sinking areas are recognized in the sedimentary record by anomalous thickenings in the alluvial deposits and fine-grained sediments deposited in backswamp and ponded areas.     

中国第四纪海面变化信息系统初探

海面变化研究是具重要理论和实践意义的地学研究领域。全球性气候变化、海面升降和环境变迁的预测等研究,引起国际学术界和各国政府部门高度重视,成为国际地圈－生物圈计划