东太平洋沉积物U的地球化学

本文对地矿部“海洋四号”科学考察船１９８７－１９８９年在东赤道太平洋ＣＣ区所取得的２７个深海表层沉积样品进行Ｕ的地球化学分析，探讨了Ｕ在深海沉积中的地球化学行为，结果表明，不同类型沉积的Ｕ含量不同，平均值由大至小的次序的含沸石粘土（２．１６×１０＾－６），硅质粘土（１．９５×１０＾－６），硅质软泥（１．６５×１０＾－６），钙质硅质粘土（１．５９×１０＾－６），在同类型沉积中Ｕ的分散性较大；Ｕ在区域     

青藏高原中部湖泊沉积物中Zr/Rb值及其环境意义

由于青藏高原及其周边地区构造复杂,湖泊沉积物中的粒级差别很大,单一的测量方法往往难以奏效。Rb、Zr是表生地球化学过程中的稳定元素,但它们之间也存在显著差别,Rb一般富集在细颗粒中,Zr则在粗颗粒中含量较高。研究发现,湖泊沉积物中Zr/Rb比值与粘土(<2μm)含量存在显著相关,Zr/Rb值反映了湖泊沉积物的粒度大小。Zr/Rb比值所揭示的青藏高原中部280万年来经历的3次大的环境演化过程与岩性变化、孢粉指标反映的环境特征是一致的。     

A depocenter of organic matter at 7800 m depth in the SE Pacific Ocean

The Atacama trench, the deepest ecosystem of the southern Pacific Ocean (ca. 8000 m depth) was investigated during the Atacama Trench International Expedition. Sediments, collected at three bathyal stations (1040–1355 m depth) and at a hadal site (7800 m) were analyzed for organic matter quantity and biochemical composition (in terms of phytopigments, proteins, carbohydrates and lipids), bacterial abundance, biomass and carbon production and extracellular enzymatic activities. Functional chlorophyll-a (18.0±0.10 mg m⁻²), phytodetritus (322.2 mg m⁻²) and labile organic carbon (16.9±4.3 g C m⁻²) deposited on surface sediments at hadal depth (7800 m) reached concentrations similar to those encountered in highly productive shallow coastal areas. High values of bacterial C production and aminopeptidase activity were also measured (at in situ temperature and 1 atm). The chemical analyses of the Atacama hadal sediments indicate that this trench behaves as a deep oceanic trap for organic material. We hypothesize that, despite the extreme physical conditions, benthic microbial processes might be accelerated as a result of the organic enrichment.     

Heavy metals in marine sediments of Taranto Gulf (Ionian Sea, Southern Italy)

Al, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Ti and Zn concentrations have been determined in surface sediment samples collected in the Taranto Gulf (Ionian Sea, Southern Italy) in order to evaluate their levels and spatial distribution in this important area of the Mediterranean Sea. For various metals, the geoaccumulation index has been calculated as a criterion to assess if their concentrations represent contamination levels or can be considered as background levels. The results show that metals concentrations in sediments can be considered near the background levels found in the Mediterranean Sea.Analytical results have been elaborated by using a Geographical Information System (GIS) software to show metals accumulation areas. Using multivariate statistical analysis, we evaluate the possibility to distinguish the sampling stations, in relation to their geographical position. Results have showed metals distribution in the Taranto Gulf is principally influenced by industrial and urban wastes, located mostly in the northern coastal area of the Ionian Sea. Rivers in the Basilicata region and prevailing anticlockwise marine currents are further factors influencing metal accumulation in sediments.     

运城盆地11 kaBP以来气候环境变迁与湖面波动

通过黄土区湖泊沉积研究来恢复古气候、古环境，是对黄土区古气候、古环境研究的补充和检验。通过山西运城盆地硝地湖泊沉积物的多环境代用指标分析，结合史料记载，探讨了该地区11kaBP以来古气候演化和湖面波动的历史。结果表明，该地区存在YD（Younger Dryas）事件，进入全新世后气候有显著的趋势，最高湿润度发生在7．88－5．15和5kaBP后，气候逐渐变干，湖面波动与气候波动相关，全新世早期湖面开始上升，湖泊扩张，5kaBP后湖泊萎缩，盐类结晶析出。     

Large-scale environmental influences on the benthic macroinfauna of the southern Gulf of Mexico

The influence of large-scale natural disturbance from winter storms (‘northers’) and river runoff on the macrobenthic community structure of the southern Gulf of Mexico was investigated in both carbonate and transitional carbonate–terrigenous sedimentary environments. Samples of the infauna were obtained in three seasons from 13 stations from two 250 km transects along 80–170 and 20–50 m water depth. Samples after the northers season had the lowest total number of families and individuals, 114 and 2940, respectively, compared to the dry and rainy seasons with 129 and 132 families and 11580 and 15266 individuals, respectively. Spatial patterns of macroinfauna composition varied across and along the shelf as a response to sedimentary environments and depth. Coarser sediments from the carbonate area harboured the highest mean densities per station with 500–24,000 individuals m⁻² and 108–122 families in total, compared to the transitional sediment with 500–8200 individuals m⁻² and 56–74 families across the three seasons. Univariate and multivariate statistical techniques demonstrated that low densities and number of taxa were associated with winter storms, but storm influence was dependent on depth and sediment type. Multiple linear regression analysis and BIOENV analysis indicated that sediment mean grain size, percentage of clay and organic matter best explained the macroinfauna spatial patterns, although BIOENV indicated that depth has an overriding role. An increase in densities of opportunistic taxa (numerous polychaetes of small sizes) was observed four months after the ‘northers’ and this was more evident in the area of carbonate sediment. Additionally a combined disturbance from northers and river runoff is suspected to be responsible for a naturally impoverished macroinfauna community in the transitional sedimentary environment.     

Meiobenthic Organisms as Indicators of Mixing Processes in the Baltic Surface Sediments*

Abstract. Two sediment cores were collected in the southern Baltic Sea and sliced into 1.0cm-thick layers. Sediments of each layer were analysed for activities of ²¹⁰Pb, ¹³⁷Cs, ¹³⁴Cs and for the density of meiobenthic organisms (meiofauna). Zones with the rapid mixing occur in the uppermost layers (0–3 cm) of the cores based on ^I34Cs profiles. The extent and density of meiofauna confirmed the rapid mixing and revealed layers with slow mixing (4–8 cm). Sedimentation rates were derived from ²¹⁰Pb profiles below the mixing zones (1.21 and 1.72 mm a-^I) and were confumed by ¹³⁷Cs distribution. Of twenty-one major meiofauna taxa commonly found in the Baltic sediments, three were present in the cores.     

南四湖,东平湖资源综合开发问题探讨

南四湖，东平湖是华北重要的淡水湖，湖区自然条件优越，资源丰富，有巨大开发潜力。本文分析湖区资源特征，开发利用现状和存在问题，提出合理开发利用途径与对策。     

渤海、黄海、东海沉积物中矿物组合的研究

本文对黄海、渤海、东海以及长江、黄河、辽河表层沉积物中的轻、重矿物进行了研究。分析资料表明,调查区内共有三种类型的矿物:陆源矿物、自生矿物和海底火山喷发形成的火山型矿物。根据轻、重矿物组合的差异,可把调查区分成8个矿物区。其物质来源主要为黄河与长江。黄河物质主要沉积在黄海、渤海;长江物质沉积在东海陆架区,而冲绳海槽则发现有海底火山喷发物质与浊流沉积。     

南极长城湾沉积物中的自然金

作者在南极长城湾沉积物中首次发现金矿化、自然金和含金的碲、铋、锑化合物。本文着重报导了自然金特征、成色、共生矿物和物质来源等问题。