粤北区域水循环的影响及生态效应研究

如何既高速发展经济,又保护区域环境,使山区经济进入可持续发展的良性循环,对经济正处于转型阶段的粤北来说是十分关键的战略性问题。研究粤北的地表、地下水状况和规律调查,探讨生态破坏的程度以及修复的可能性,提出可行的治理对策。构建人与自然协调的地表、地下水循环系统以及相关的生态环境系统,使人与自然进入可持续发展的良性循环。     

Water wars in the Middle East: a looming threat

This paper explains how hydropolitical dynamics and spatial variables almost triggered a water war between Israel and Lebanon because the latter was building a pump on the Wazzani Spring, a tributary of the Jordan River. The convergence of a regional drought, history of violent confrontations between the two riparians, distrust, varying development needs and territorial disputes almost culminated in a war between these east Mediterranean neighbours. While most international water disputes in the Middle East will be resolved peacefully, some are likely to trigger violent confrontations threatening political stability in the Middle East in the next few decades.     

Diurnal variation in relative photosynthetic performance of marestail (Hippuris vulgaris Linn.) Across a water temperature gradient using PAM fluorometry in Jiuzhaigou National Nature Reserve, Sichuan Province, China

This paper reports the first photosynthetic study of marestail in Jiuzhaigou. In this work, we used PAM fluorometry to examine photosynthetic rates of submerged and emerged marestail in three lakes. Three lakes were studied across a gradient of water temperature, with low water temperature conditions in Grass Lake and Arrow Bamboo Lake, and higher water temperature in Five Colored Lake. In the field, electron transport rates (ETR_max) were measured as rapid light curves (RLCs) by in situ yield measurements. Submerged and emerged marestail showed higher photosynthetic activity in Five Colored Lake compared to the other lakes, a response consistent with the adaptation of marestail in Five Colored Lake to high water temperature. The optimal temperature for photosynthesis of submerged marestail in Jiuzhaigou was about 12 °C. Nonphotochemical quenching (NPQ) of submerged and emerged marestail increased with increasing water temperature. Maximum quantum yield (F _v/F _m) of submerged marestail in Five Colored Lake showed full recovery at 1700 h due to higher NPQ. Further, the chlorophyll a for submerged marestail was the highest in Grass Lake and the lowest in Five Colored Lake. These results indicate that in different lakes the function of these aquatic plants is associated with a diversity of place-dependent environmental conditions, especially water temperature that leads to pronounced differences in the plant’s ecophysiological reactions.     

隔水隔泥岩土盘构成及其破坏模式研究

隧道施工开挖接近开挖工作面前方存在的突水突泥致灾构造,或通过隧道开挖轮廓线外存在的突水突泥致灾构造,由于开挖工作面与开挖工作面前方存在的突水突泥致灾构造间或开挖轮廓线与开挖轮廓线外存在的突水突泥致灾构造间隔水隔泥岩土盘厚度小于最小安全岩土盘厚度,隔水隔泥岩土盘在突水致灾构造中地下水或突泥致灾构造中黏土应力作用下失稳破坏,导致隧道施工突水、突泥灾害发生。本文以统计近十多年的隧道施工突水突泥灾害实例,以此为基础总结提出了导致隧道施工突水突泥灾害发生的隔水隔泥岩土盘构成类型及其破坏模式,分析提出了5种隔水隔泥岩土盘类型：夹黏土或不夹黏土的大小不一的破碎岩石块体（岩石颗粒、砂夹卵石）、裂隙黏土充填或裂隙密闭无充填的节理裂隙化岩体、黏土或断层泥、完整岩体、初期支护隔水隔泥岩土盘,并在这5种隔水隔泥岩土盘类型的基础上,提出了5种破坏模式：渗流（溃散）破坏、剪切破坏、软化破坏与爆裂破坏、断裂/爆裂破坏、弯断破坏;分析了隔水隔泥岩土盘构成类型与破坏模式间的相互关系。     

The origin of the Pedra Furada sandstone tubular structures (South of Lisbon, Portugal)

The Pedra Furada is a 12 m wide, 18 m high outcrop feature showing hundreds of ferruginised sandy tubes and looking in part like a giant organ. In this paper the origin of the tubes is explained on the basis of geochemical, petrographic and microscopic (optical and electronic) analytical data. The tubes are considered to represent vertical escape channels for overpressured water, exhibiting inward decreasing grain size due to water velocity gradients inside the escape channels. The ferruginisation is due to iron oxides associated with colloidal/clayey fine sediments and to goethite formed from solution. The overpressure of water may be due to seismically fluidised beds below the Pedra Furada outcrop or to artesian water ascent. In both cases, fault rupturing may have played a major role in the focussing of the ascending flow.     

辽东湾北部钻孔磁性地层年代框架及地质意义

辽东湾地属渤海,其沉积历史和特征,是揭示渤海海域晚新生代以来构造演化与地理格局形成过程的重要窗口。目前该区缺少精确年代学控制的长序列研究钻孔。文章基于磁性地层学方法,结合粒度分析、AMS ¹⁴C测年和光释光测年数据,建立了该区北部JXC-1孔和YKC-2孔的年代地层框架。JXC-1孔地理坐标为40°24'43.38″N,121°03'23.37″E,水深约22 m,进尺70.3 m,取芯率89.2%;YKC-2孔地理坐标为40°25'53.95″N,121°36'30.20″E,水深约14 m,进尺70.1 m,取芯率85.3%。研究结果显示：JXC-1孔底界年龄为1.2 Ma,YKC-2孔底界年龄为0.7 Ma。根据沉积速率特征,JXC-1孔可分为2个阶段：阶段Ⅰ年龄为0~0.78 Ma,埋深0~45.18 m,沉积物以粉砂、细砂为主,位于布容正极性时（Brunhes）,记录了Mono Lake、Levantine-Biwa Ⅲ和Calabrian Ridge Ⅱ等极性事件;阶段Ⅱ年龄为0.78~1.20 Ma,埋深45.18~70.30 m,沉积物以粉砂为主,位于松山负极性时（Matuyama）,贾拉米洛正极性亚时（Jaramillo）埋深为61.6~66.2 m。YKC-2孔主要位于布容正极性时（Brunhes）上部,包括Gothenburg、Blake等极性事件。JXC-1孔的布容松山倒转边界（MBB）位于45.18 m,与渤海及周边其他钻孔存在较大差别,YKC-2孔则未打穿MBB。通过不同构造单元沉积记录和新构造运动响应对比,发现辽东湾北部晚更新世以来沉积厚度存在"东厚西薄"的模式。整个渤海及周边地区沉积相对连续,沉积厚度呈现以渤中坳陷为中心向四周减薄的特征。这表明,在新近纪构造基底控制的基础上,受郯庐断裂晚更新世以来的活动性影响,叠加了区域新构造运动,二者共同控制了区域内沉积厚度差异。这一研究深化了该区构造及沉积演化模式。

     

城市中心体系研究的理论基础与分析框架

“经济—空间”视角下城市中心体系的理论与实证研究之间缺少相互衔接的分析框架。论文通过对经典理论的系统归纳与演绎,建立整体视角下理解城市中心体系形成与发展的理论框架,将城市中心体系的发展规律概括为空间竞争和空间联系2个机制,体现在本地服务功能和非本地功能的空间组织过程,分别形成等级网状结构和专业化点状结构,并相互融合形成“半网格”的城市中心体系,扮演着本地与宏观区域结构之间的“转换发动机”。最后探讨了对实证研究的若干启示,提出城市中心的定义和识别方法应注意与理论研究相互衔接;认为城市中心的本地/非本地功能特征及相应的发展机制亟待实证;认为中心及其空间影响的调控潜力是制定规划政策的前提。     

人地系统耦合下生态系统服务与人类福祉关系研究进展与展望

21世纪以来生态系统服务退化与人类需求提升间的矛盾愈发激烈,如何有效推进生态系统服务与人类福祉的协调平衡成为当前可持续发展的核心主题.论文通过梳理生态系统服务与人类福祉关系研究的阶段演进发现,现有研究主要从服务对福祉的影响与福祉对服务的反馈切人,逐步聚焦到供需关系与空间流动、权衡/协同的利益博弈、文化服务的价值化、生态...     

地幔中的水与熔融

自二十世纪九十年代起,通过对天然样品的观察、矿物中水的溶解度的实验研究、以及地球物理的观测,人们逐步认识到地球内部以矿物晶格缺陷形式蕴含着至少与现今海洋水量相当的水。地球内部的水除了显著影响矿物的热导率、电导率、流变学、扩散等性质之外,还对不同构造背景下的地幔熔融产生了重要影响。水作为强不相容元素,在地幔发生熔融时会更倾向于进入到熔体相中,从而改变熔体的结构,影响与残留固相之间的平衡。总体上讲,在等温等压条件下,地幔中水的存在可以显著降低其固相线并增大熔融程度;而在绝热减压过程中,水的存在则可以加深初始熔融的深度,增大地幔整体熔融的区间,从而降低平均熔融程度。近年来,越来越多的证据表明,水对于从岩石圈-软流圈边界的低程度熔融到地幔超大规模熔融产物（大火成岩省）的形成都具有重要作用。本文综述了不同构造背景下（大洋中脊、岛弧、地幔过渡带、大火成岩省、大陆板内、洋岛等）水对地幔熔融影响的新进展,并提出现有研究的不足和未来的挑战。