浙江省落花Yang地区成矿远景浅析     

童朝旭 《浙江国土资源》2003,(3):36-40

浙江省落花垟地区位于闽浙交界的庆元县,为丽水-政和大断裂通过处,并是中元古界地层龙泉群(浙江省)与马面山群(福建省)接壤部位。近20年来,福建省在地质找矿方面取得了重要的突破,相继发现了上杭紫金铜金大型矿床、梅仙式大型铅锌银多金属矿床等一批在东南沿海具有里程碑式意义的典型矿床。相对而  相似文献   

DSDP／ODP 1—126航次岩心中的锰沉积物（续一）     

孙克虬 《海洋地质信息通报》1994,(10):10-11

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TRANSFERABLE PHOSPHORUS IN SEDIMENTS OF THE HUANGHE RIVER ESTUARY ＇S ADJACENT WATERS   总被引：1，自引：0，他引：1  

宋金明 《中国海洋湖沼学报》2001,19(1):81-86

Based on a new idea for research on cycling of marine biogenic elements, this study showed that only the leachable form phosphorus in natural grain sizes manne sediments constitutes the transferable phosphorous in the sediments. The transferable phosphorus content in the natural grain sizes surface sediments in the Huanghe River estuary adjacent waters ranges from 58.5-69.8 μg/g, accounting for only 9.1%-11.0% of the total phosphorus content, whereas the leachable form (“transferable” )phosphorus content in the sediment after it was totally ground into powder was found to be 454.8-529.2μg/g, accounting for 73.4%-89.1% of the total phosphorus. Analysis of the correlation between thebill,ass of benthos and the leachable form (“transferable” ) phosphorus showed that most of the leachableform (“transferable”) phosphorus in the totally ground sediment did not participate in the marine biogeo chemical cycling. Furthermore, a synchronous survey on benthos showed that the biornass of meio-and maero-benthos exhibited good positive correlation with the leachable form of phosphorus in the naturalgrain sizes sediment, but peorer correlation with the leachable form (“transferable”) phosphorus in the totally ground sediment, indicating that transferable phosphorus in marine sediment is the leachable form of phosphorus in the natural grain sizes sediments, and is not the previously known leachable form(“transferable”) phosphorus obtained from the totally ground sediment.  相似文献   

利用黄河泥沙围出“渤海湖”的初步设想   总被引：1，自引：0，他引：1  

郝戬 《地球信息科学学报》2001,3(3):76-79

本文是一个关于将渤海变成淡水湖的水利工程的构想。让黄河的大量泥沙通过人工导流的方式沿莱州湾南岸与渤海海峡沉积延伸,产生的陆地将渤海封闭并逐渐形成淡水湖。这一工程将陆地连接山东半岛与辽东半岛,并为华北提供巨大淡水库,具有显著的经济、生态效益。具体实施上,可通过两道渔网式围栏促使黄河泥沙定点沉积并阻挡浪潮侵蚀,通过加强汛期水量增加黄河口泥沙。  相似文献   

用DDT测年法测定厦门外港岩芯的现代沉积速率     

林敏基 《海洋通报》1990,9(2):88-90

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雾凇     

《山东国土资源》2007,23(11):68-68

雾凇俗称树挂,是一种冰雪美景。它是在寒冷北方冬季可以见到的一种类似霜降的自然现象,其实也是霜的一种。它是由冰晶在温度低于冰点以下的物体上形成的白色不透明的粒状结构沉积物。过冷水滴(温度低于零度)碰撞到同样低于冻结温度的物体时,便会形成雾凇。当水滴小到一碰上物体  相似文献   

大洋钻探科学家引证北极气候变化的历史——《Nature》上刊载的重要发现     

《海洋地质与第四纪地质》2006,26(4):44

《Nature》2006年第1期刊载了大洋钻探科学家们2004年秋季完成的北冰洋大洋海底钻探在报告中的新发现,该报告由IODP研究项目支持,对采自接近北极的北冰洋海底之下430 m沉积物样品进行了分析,为了恢复沉积物中史前气候记录,研究团队需要管理3个破冰机来装备1个钻机,沉积物记录的恢复来自水深大约1 000 m的Lomonsov脊。IODP北冰洋岩心勘探(ACEX)科学家在《Na-ture》报道了他们的重要发现:●北冰洋冰证据的发现远早于先前认为的45Ma;●55 Ma时,北极的温度上升至亚热带的水平(约23℃);●49 Ma时,北极是绿色的,至少在夏季表层淡水和大量…  相似文献   

《海洋地质与第四纪地质》第28卷(2008)总目录     

《海洋地质与第四纪地质》2008,28(6)

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Deepwater Ventilation and Stratification in the Neogene South China Sea     

李前裕赵泉鸿  钟广法翦知湣 田军成鑫荣  汪品先陈木宏 《中国地质大学学报(英文版)》2007,18(2):95-108

Combined data of physical property, benthic foraminifera, and stable isotopes from ODP Sites 1148, 1146, and 1143 are used to discuss deep water evolution in the South China Sea (SCS) since the Early Miocene. The results indicate that 3 lithostratigraphic units, respectively corresponding to 21-17 Ma, 15-10 Ma, and 10-5 Ma with positive red parameter (a*) marking the red brown sediment color represent 3 periods of deep water ventilation. The first 2 periods show a closer link to contemporary production of the Antarctic Bottom Water (AABW) and Northern Component Water (NCW), indicating a free connection of deep waters between the SCS and the open ocean before 10 Ma. After 10 Ma, red parameter dropped but stayed higher than the modern value (a*=0), the CaCO3 percentage difference between Site 1148 from a lower deepwater setting and Site 1146 from an upper deepwater setting enlarged significantly, and benthic species which prefer oxygen-rich bottom conditions dramatically decreased. Coupled with a major negative excursion of benthic δ13C at ~10 Ma, these parameters may denote a weakening in the control of the SCS deep water by the open ocean. Probably they mark the birth of a local deep water due to shallow waterways or rise of sill depths during the course of sea basin closing from south to east by the west-moving Philippine Arc after the end of SCS seafloor spreading at 16-15 Ma. However, it took another 5 Ma before the dissolved oxygen approached close to the modern level. Although the oxygen level continued to stabilize, several Pacific Bottom Water (PBW) and Pacific Deep Water (PDW) marker species rapidly increased since ~6 Ma, followed by a dramatic escalation in planktonic fragmentation which indicates high dissolution especially after ~5 Ma. The period of 5-3 Ma saw the strongest stratified deepwater in the then SCS, as indicated by up to 40% CaCO3 difference between Sites 1148 and 1146. Apart from a strengthening PDW as a result of global cooling and ice cap buildup on northern high latitudes, a deepening sea basin due to stronger subduction eastward may also have triggered the influx of more corrosive waters from the deep western Pacific. Since 3 Ma, the evolution of the SCS deep water entered a modern phase, as characterized by relative stable 10% CaCO3 difference between the two sites and increase in infaunal benthic species which prefer a low oxygenated environment. Thesubsequent reduction of PBW and PDW marker species at about 1.2 Ma and 0.9 Ma and another significant negative excursion of benthic δ13C to a Neogene minimum at ~0.9 Ma together convey a clear message that the PBW largely disappeared and the PDW considerably weakened in the Mid-Pleistocene SCS. Therefore, the true modern mode SCS deep water started to form only during the "Mid-Pleistocene climatic transition" probably due to the rise of sill depths under the Bashi Strait.  相似文献   

咸阳渭河高漫滩沉积洪水变化研究   总被引：6，自引：0，他引：6  

赵景波  ZHOU Xiao-hong  SUN Gui-zhen 《沉积学报》2007,25(4):597-602

根据咸阳高漫滩XY剖面中116个样品的粒度分析,结合历史文献记载的年代资料得出,渭河约120年来形成的高漫滩洪水沉积分层明显,对洪水的变化反映清楚,分辨率高,能够作为很好地指示洪水变化的指标。XY剖面最上层为2003年大洪水沉积,最上层之下的其它15层为古代洪水发生时期形成的沉积层,整个剖面记录了16次规模较大的洪水。XY剖面随深度变化具有明显的粗细变化节律,其中第1、3、5、7、9、11、13、15层粒度组成较第2、4、6、8、10、12、14、16层细。在充分考虑了因洪水沉积逐步叠加引起的地形增高对粒度成分的影响之后,可以确定这16个阶段洪水深度和规模由大到小的变化顺序为:第12阶段>第15阶段>第6阶段>第9阶段>第16阶段>第1阶段>第5阶段>第14阶段>第7阶段>第11阶段>第3阶段>第13阶段>第8阶段>第10阶段>第4阶段>第2阶段。其中第12、15、6、9、16、1阶段的洪水规模较第5、14、7、11、3、13、8、10、4、2阶段洪水规模更大。根据2003年河漫滩上的洪水沉积层粒度成分和洪水深度为2.2 m左右确定,所研究的剖面中第6、9、12、15、16、1层形成时的河漫滩上的洪水深度大于2.2 m,第5、14、7、11、3、13、8、10、4、2层形成时的洪水深度小于2.2 m。通过与现代大洪水发生时期年降水量的对比可知,这些大洪水发生的主要是渭河流域一些地区当年降水量显著增加造成的。在这16个洪水阶段之间没有洪水发生的阶段是降水量正常或偏少的阶段。  相似文献