毛乌素沙地丘间低地主要植物叶片性状及其相互关系

以毛乌素沙地丘间低地30种主要植物为研究对象,比较不同功能群植物叶片性状的变异特征,分析植物叶片各性状之间的关系。结果表明:30种植物的比叶面积的变异系数最大,比叶面积与叶片干物质含量呈现极显著的负相关关系,叶片干物质含量与叶片碳含量呈显著的正相关关系,叶氮含量与叶片碳氮比呈极显著负相关关系,叶面积与其他所有的叶片性状都无相关性。比叶面积、叶片干物质含量、叶面积、叶氮含量和叶碳含量在不同功能群之间存在显著差异,叶片碳氮比在不同功能群之间没有显著差异。研究结果有助于了解毛乌素沙地丘间低地环境变化对植物种群的作用,增进对丘间低地植被演变特征的认识。     

重庆地区红层泥岩球状风化剥落特征及其形成机制

以重庆地区红层泥岩为对象,对其球状风化剥落的形貌、剥落层序、剥落层层数、剥落层厚度、剥落物形态及其堆积特征等进行了分析。调查和分析表明,泥岩球状风化是水分场、温度场有关的各种风化作用共同作用的结果,其风化剥落经历了局部变形与应力集中、风化裂隙切割、椭球化、拱形开裂与球状逐层剥落的过程。红层泥岩球状风化剥落速度快,风化球因分叉明显,稳定性差,难以长久保留。     

辽河坳陷双清地区古近系沙河街组四段孔隙度演化模拟

在综合考虑沉积微相和成岩作用对储集层孔隙度影响的基础上,建立了辽河坳陷双清地区不同沉积微相成岩指数ID与储集层平均孔隙度的相关关系,预测了该地区沙四段储集层在各沉积时期的平均孔隙度,恢复了孔隙演化史,确定了不同沉积时期有效油气储集层的分布范围。孔隙度预测结果表明,有效油、气储集层分布于研究区北部孔隙度大于58％的地区。孔隙演化史的模拟结果表明,储集层孔隙度在埋藏早期主要受沉积相的影响,而在晚期则主要受成岩作用的控制。储集层预测孔隙度与实测孔隙度的绝对误差为2.7％.,而研究区储集层的填隙物含量在1.0％～40.0％之间,平均为21.7％.,由此可见,所建预测模型可用于填隙物含量较高的储集层钻前孔隙度预测和孔隙演化史模拟。     

Contribution of subducted Pacific slab to Late Cretaceous mafic magmatism in Qingdao region, China: A petrological record

Abstract The occurrence of the Pishikou mafic dike in the Qingdao region, China provides important constraints on the origin of Late Cretaceous (86–78 Ma) mafic magmatism on the eastern North China craton. The Pishikou mafic dike is distributed in the Cretaceous Laoshan granitoid body, Qingdao region and contains peridotitic and granulitic xenoliths, xenocrysts, and megacrysts. Rocks from the Pishikou mafic dike are basanites and have low SiO₂ (< 42 wt%) and Al₂O₃ (12.5 wt%) contents, and high MgO (> 8 wt%), total alkalis (Na₂O + K₂O > 4.8 wt%, Na₂O/K₂O > 1), TiO₂ (> 2.5 wt%), CaO (> 9 wt%) and P₂O₅ (> 1 wt%). In trace element abundances, they are highly enriched in large ion lithophile elements (LILEs) and light rare‐earth elements (LREEs) (ΣREE = 339–403 ppm, (La/Yb)_N = 39–42) without high field strength element (HFSE) depletion. These rocks have radiogenic Sr and Pb, and less radiogenic Nd isotopic compositions [(⁸⁷Sr/⁸⁶Sr)_i > 0.7059, εNd ≈ 2.7–3.8 (²⁰⁶Pb/²⁰⁴Pb)_i ≈ 18.0 ± 0.1]. The diagnostic elemental ratios, such as Nb/La, Nb/U, and Nb/Th, are compatible with those of mid‐oceanic ridge basalts (MORBs) and oceanic island basalts (OIBs). Therefore, the Pishikou mafic dike has a geochemical feature completely different from those of the Early Cretaceous mafic dikes from the Qingdao region, but similar to those of back‐arc basalts from the Japan Sea. This geochemical feature suggests that the Pishikou mafic dike was derived from an asthenosphere source, but contaminated by materials from the subducted Pacific slab. The discovery of this mafic dike thus provides a petrological evidence for the contribution of subducted Pacific slab to the Late Cretaceous magmatism in the Qingdao region of the eastern North China craton.     

中国钻孔体应变仪同震变化观测结果

同震形变反映了来自震源区的变化,它是建立地形变与地震之间关系的最直接桥梁,因而对地震预报有至关重要的意义.钻孔体应变仪属于高精度地形变观测仪器,最适合揭示短期形变变化.我国使用的体应变仪分为两类,一类是从美国华盛顿卡耐基研究所引进的sacks型体应变仪(6套),另一类是中国地震局地壳应力研究所研制的TJ型体应变仪(约80套).     

Depositional model of Permian Luodianian volcanic island and its impact on the distribution of fusulinid assemblage in southern Qinghai, Northwest China

Pan-riftizational tectonic activity reached climax at Luodianian (Permian) in the East Tethyan Domain, Qinghai-Tibet Plateau. Because of eruptive volcanics and influence of terrigenous materials, a complex volcanic-sedimentary landform formed on the sea floor in southern Qinghai. Four sedimentary facies types were recognized based on detailed field mapping. Spatially, platform facies volcanic-limestone type was located at the center belt approximately trending NWW, surrounded by shallow water slope facies tuff/tuffite type at the two flanks and deep water slope facies breccia/calcirudite at the most outside. The depression facies sandstone-mudstone type, which comprised mainly mudstone, de-posited between volcanic islands (platform facies volcanic-limestone type). Based on the field map-ping and stratigraphic section data, seven rift-related sedimentary facies were recognized and a depo-sitional model for volcanic island was proposed. It is revealed that some volcanic island chain formed quickly and intermittently in the Qamdo Block during violent eruption, and small carbonate reef, shoal, platform occurred above or on edge of volcanic island, and some slope sedimentary facies surrounded volcano island chain during dormant period of volcanic activities. Three types of fusulinid assemblages were distinguished in the carbonate rocks, which deposited in varied positions of a palaeo-volcanic island: (1) Misellina-Schwagerina assemblage occurred above or on edge of volcanic island, (2) Para-fusulina assemblage was located at restricted depression facies among volcanic islands or carbonate platform, and (3) the reworked Pseudofusulina-Schwagerina assemblage occurred at slope facies near margin of volcanic island, which originally deposited in the shallow-water carbonate platform, then collapsed along the volcanic island margin with fusulinid-bearing grain-supported carbonate con-glomerate or calcirudite, and finally re-deposited on the deeper slope. The sedimentary sequence re-sulting from calm shallow water was deposited at the interior of the Qamdo Block from the Devonian to early Early Permian. At the beginning of the peak period of activity of pan-riftzation (Luodianian), al-ternate volcanic island and shallow marine environment within continent crust came into being. Uni-form and stable shallow-water carbonate platform was formed during the Xiangboan. This suggested that the activity of rift basin was evidently weakened. Subsequently the instability of the basin appre-ciably increased with the occurrence of basalt in late Kuhfengian. At last the whole Qamdo Block turned into the closure period of rift during the Late Permian.     

太行山北段深源流体与金矿成矿作用

太行山北段金矿研究表明,金的成矿物质主要来自深源,部分萃取自迁移途中的围岩。成矿具有明显的成矿集中期和集中区,这种时间、空间分布特征与地幔热柱多级演化密切相关。含金的深源流体随地幔热柱多级演化向上迁移,当其迁移到幔枝（变质核杂岩）外围主拆离滑脱带及其上盘裂隙扩容带时,由于物理、化学条件的改变,使其聚集沉淀成矿,并可表现出斑岩脉型、隐爆角砾岩型、大脉型、网脉型等多种矿石类型为一体的系列成矿。硫、铅、     

湘赣地区龙潭煤系的成煤背景与煤层气

湘赣地区龙潭煤系是华南重要的含煤地层之一,煤层气资源丰富,是浅层煤层气开发利用的理想场所。本文分析了湘赣地区龙潭煤系的成煤古地理条件及大地构造环境,在此基础上讨论了龙潭煤系的原始生气能力、储集层及围岩的储气能力,并讨论了印支运动和燕山运动对煤层气富集、分布的影响      

高光谱遥感影像优化分类波段选择

利用粗糙集关于属性依赖性公式,本文给出一种定义遥感影像波段间相似度的方法。通过模糊聚类,得到对高光谱遥感影像原始波段集合的模糊等价划分。在每个模糊等价波段组中,选择一个代表性波段完成对原始波段集合的初步降维。基于遗传算法并结合粗糙集理论,在降维后的波段集合中进一步进行的分类波段组合的优化选择。实验结果表明,本文给出的高光谱遥感影像优化分类波段组合选择方法是非常有效的。     

华北陆块早三叠世刘家沟组古地磁学新数据

在河北武安大淑村刘家沟组布采点１３个,采样９１个,进行了古地磁学研究,研究结果表明,华北陆块与陆块在早三叠世时尚未形成一体,自上三叠世至今,华北陆块以反时针,扬子陆块以顺时针,各自旋转了数十度。