试说中国陆内构造变形和其地球动力学特征

中国陆内构造变形主要始于晚二叠世中国北方进入后海西地台发展时期。印支期末以至喜马拉雅期,随着特提斯洋的关闭,大陆范围也随即向中国南方和青藏地区增生和扩展。中国的陆内构造变形从后海西地台形成的准平原化阶段即已开始。但规模巨大的变形则发生于燕山构造旋回中期和喜马拉雅旋回。陆内构造变形的规模可分两个等级:一是覆盖整个中国大陆的,另一是局部的。前者两次改变了中国构造-地貌的整体面貌;后者则表现为造山、造盆和微陆块纵向或横向的逃逸,以及由此引起的造山或造盆。根据中国陆内构造变形特征及其与区域构造背景演化的关系分析认为,中国陆内构造变形主要是由周边洲级规模板块运动引起的,同时,随着地壳上部构造变形引发的地壳或岩石圈均衡调整,则使地下深处产生相应的构造响应。     

陇东新近纪红粘土与第四纪黄土地球化学特征及其物源和风化指示意义

甘肃省平凉市灵台县邵寨镇剖面风尘堆积底界年龄大约为5.23 Ma B.P.,通过对该剖面新近纪红粘土与第四纪黄土-古土壤序列的常量元素、 微量元素、Nd同位素的测试,分析其在物源和风化方面的指示意义,发现新近纪红粘土与第四纪黄土具有相似的常量、 微量元素UCC标准化曲线和稀土元素球粒陨石标准化曲线,指示二者皆来自广阔的...     

The Quaternary Lancaster Sound trough‐mouth fan,NW Baffin Bay

The development of the Lancaster Sound Trough Mouth Fan (TMF) and glacial history in Arctic Canada were studied using a high‐resolution seismic profile across the entire fan and two piston cores. Stacked tills separated by erosion surfaces on the shelf pass seaward through till deltas into thick transparent glacigenic debris flow (GDF) deposits on the slope, separated by thin, well‐stratified glaciomarine layers. An age model was built by ties to the Ocean Drilling Program Site 645. The deepest GDF on the seismic profile was indicative of the onset of shelf‐crossing glaciation in the Early Pleistocene. The transition of the growth of Lancaster Sound TMF from an aggradational sequence (unit M) to an aggradational–progradational sequence (unit F) occurred at the Middle Pleistocene transition in glacial cyclicity. In the most recent glacial cycle, GDF sheets were deposited during Heinrich events 4 and 2 according to the correlation of the main detrital carbonate beds in two piston cores. The outmost till wedge reflects the maximum advance of the grounding glacier, far seaward of previously proposed Last Glacial Maximum ice extent. Copyright © 2011 John Wiley & Sons, Ltd.     

Late Quaternary stratigraphy and sedimentology of the inner part of southwest Joseph Bonaparte Gulf

Joseph Bonaparte Gulf is a large embayment on the northwestern continental margin of Australia. It is approximately 300 km east‐west and 120 km north‐south with a broad continental shelf to seaward. Maximum width from the southernmost shore of Joseph Bonaparte Gulf to the edge of the continental shelf is 560 km. Several large rivers enter the gulf along its shores. The climate is monsoonal, sub‐humid, and cyclone‐prone during the December‐March wet season. A bedrock high (Sahul Rise) rims the shelf margin. The sediments within the gulf are carbonates to seaward, grading into clastics inshore. A seaward‐thinning wedge of highstand muds dominates the sediments of the inner shelf of Joseph Bonaparte Gulf. Mud banks up to 15m thick have developed inshore. Coarse‐grained sand ridges up to 15 m high are found off the mouth of the Ord River. These overlie an Upper Pleistocene transgressive lag of mixed carbonate and gravelly siliciclastic sand. Four drowned strandlines are present on the inner shelf at depths of 20, 25, 28 and 30 m below datum. These are interpreted as having formed during stillstands in the Late Pleistocene transgression. Older strandlines at great depths are inferred as having formed during the fall in sea‐level following the last highstand. For the most part the Upper Pleistocene‐Holocene marine sediments overlie an erosion surface cut into older Pleistocene sediments. Incised valleys cut into this erosion surface are up to 5 km wide and have a relief of at least 20 m. The largest valley is that cut by the Ord River. Upper Pleistocene sediments deposited in the incised valleys include interpreted lowstand fluvial gravels, early transgressive channel sands and floodplain silts, and late transgressive estuarine sands and gravels. Older Pleistocene sediments are inferred to have been deposited before and during the 120 ka highstand (isotope stage 5). They consist of sandy calcarenites deposited in high‐energy tide‐dominated shelf environments. Still older shelf and valley‐fill sediments underlie these. The contrast between the Holocene muddy clastic sediments and the sandy carbonates deposited by the 120 ka highstand suggests that either the climate was more arid in the past, with less fluvial transport, or that mud was more effectively trapped in estuaries, allowing development of carbonate depositional environments inshore.     

The last deglaciation in the Picos de Europa National Park (Cantabrian Mountains,northern Spain)

A sedimentological and geochemical study of the Lago Enol sequence (Cantabrian Mountains, northern Spain), together with detailed geomorphological mapping, provides a first record of glacier evolution and climate change over the last 40 ka in the Picos de Europa National Park. The Enol glacier retreated from its maximum extent prior to 40 ka BP as demonstrated by the onset of proglacial lacustrine sedimentation in two glaciated depressions: the Comella hollow to the north (before 40 ka BP) and the Lago Enol (before 38 ka BP). These results support previous evidence that the maximum extent of southern European glaciers occurred earlier than in northern Europe. Alternation of homogeneous and laminated proglacial sediments during the glacier retreat illustrate a dynamic glacial evolution during the Marine Isotope Stage (MIS) 3 (40–26 ka BP). A slight warming is detected at 26 ka ago with the change from proglacial sediments (in a lake located in contact to the glacier) to glaciolacustrine sedimentation (in a non‐contact or distal lake). Finally, the onset of organic‐rich sediments took place at 18 ka ago. This last transition occurred in two phases, similarly to the North Atlantic Last Termination, suggesting a link between North Atlantic Deep Water formation oscillations and palaeohydrological variability in the Cantabrian Mountains. Copyright © 2009 John Wiley & Sons, Ltd.     

中国沙漠植物学术语注释

注释并举例说明我国沙区植物常用术语，如短生植物、类短生植物、替代种、特有种、属的起源中心、发展中心、演替、顶极、偏途顶极等。     

林超的学术思想与成就

林超是著名的中国当代地理学家,他在长达60多年的地理科学研究和教学生涯中,博学精思,成果累累。本文从地理学理沦、地理学方法论、综合自然地理学、中国地理学史、地理教育、中外地理学交流、治学之道等方面,概括了他的学术思想和学术成就。     

我国大陆及其邻区6级以上地震的“缺震事件”——一种大地震中期预测指标的分析研究

在内陆强震活动的起伏中,6级以上地震的大范围长时间缺震,具有重要的意义。有的研究者已将其作为将发生7级地震前的标志之一。作者系统地清理了1897—1988年8月间中国大陆及其邻区6级以上地震“缺震事件”的始末,较多的震例表明,限定“缺震事件”起止的地震具有中期预报意义。它们在地震构造上的原因可能是代表区域最活跃的破裂,突然处于阻碍、闭锁状态,其持续时间大于10个月,再次发生6级以上地震为解锁,并随即出现新的一轮大地震活动。故可以作为一种大地震中期预测的指标。