Describing alpine lake influence on stream network temperatures: A statistical modelling approach     

Samuel P. Carlson  Geoffrey C. Poole 《水文研究》2021,35(3):e14072

Systematic variations in atmospheric heat exchange, surface residence time, and groundwater influx across montane stream networks commonly produce an increasing stream temperature trend with decreasing elevation. However, complex stream temperature profiles that differ from this common longitudinal trend also exist, suggesting that stream temperatures may be influenced by complex interactions among hydrologic and atmospheric processes. Lakes within stream networks form one potential source of temperature profile complexity due to the spatially variable contribution of lake-sourced water to stream flow. We investigated temperature profile complexity in a multi-season stream temperature dataset collected across a montane stream network containing many alpine lakes. This investigation was performed by making comparisons between multiple statistical models that used different combinations of stream and lake characteristics to represent specific hypotheses for the controls on stream temperature. The compared models included a set of models which used a topographically derived estimate of the hydrologic influence of lakes to separate and quantify the effects of stream elevation and lake source-water contributions to longitudinal stream temperature patterns. This source-water mixing model provided a parsimonious explanation for complex stream-network temperature patterns in the summer and autumn, and this approach may be further applicable to other systems where stream temperatures are influenced by multiple water sources. Simpler models that discounted lake effects were more optimal during the winter and spring, suggesting that complex patterns in stream temperature profiles may emerge and subside temporally, across seasons, in response to diversity of water temperatures from different sources.  相似文献   

利用InSAR资料反演宁洱Ms6.4地震震源参数及库仑应力变化     

陈晨月  冯光财  高华  杨怀宁 《大地测量与地球动力学》2019,39(3):295-301

首先利用ALOS PALSAR数据，通过D-InSAR技术获取2007-06-03云南宁洱MS6.4地震的同震形变场，然后基于Okada弹性半空间位错模型反演该地震的断层几何以及精细滑动分布，最后计算宁洱地震后周边断层的静态库仑应力变化。结果表明，形变主要集中在西盘，最大视线向形变量为51.6 cm；反演得到的震源位置为23.05°N、101.02°E，深度3 km，断层走向145°，倾向49.5°，平均滑动角153°，发震断层为NNW向普洱断裂，断层活动以右旋走滑为主，兼具逆冲分量；断层面最大滑动量为1.2 m，反演得到的震级为MW619。基于库仑应力场发现，磨黑断裂处于库仑应力增加区域，而2014年景谷地震位于负值区域。结合实地考察资料和反演结果表明，宁洱地震为浅源地震，但断层并未出露地表。  相似文献   

烃源岩不同性质有机酸的分离及其检测方法     

杜佳宗  何蓓  蔡进功  雷天柱  刘庆  谢忠怀 《高校地质学报》2020,26(5):540-548

烃源岩中的有机酸来源于有机质，但有机质具有不同的赋存形式，有机酸具有不同性质，这将影响有机酸与不同赋存有机质的关系，进而影响分离和检测方法。文章在总结前人对有机质赋存形式和有机酸性质等特征的基础上，提出烃源岩中的有机酸并以非单一的形式存在，具有水溶性、脂溶性和难溶性有机酸三种类型，游离有机质中存在水溶性和脂溶性有机酸，而结合有机质中存在水溶性、脂溶性和难溶性有机酸。因此在检测方法上需采取分步分离的方法，且根据有机酸的性质选取合适的检测方法，即水溶性有机酸利用离子色谱检测，索氏抽提得到的脂溶性有机酸利用气相色谱—质谱检测，通过酸解抽提残渣得到的难溶性有机酸利用红外光谱检测，全面系统地认识烃源岩中有机酸含量和类型等特征。这对进一步探讨烃源岩各种类型有机酸特征和演化规律，深化烃源岩有机质生烃以及有机—无机相互作用等机理都具有重要意义。  相似文献   

岩溶水硝酸盐污染原位修复试验     

叶进霞  夏春英  卜鸿志 《中国岩溶》2020,39(2):173-179

岩溶含水层的极不均一性特征使岩溶水溶质运移受构造、裂隙空间及其发育方向控制；因环境条件复杂，开展岩溶水污染原位修复技术难度较大，截止目前，国内尚未系统地开展岩溶含水层水污染原位修复研究工作。文章选择鲁中南山区典型岩溶发育及硝酸盐污染地段，施工组合钻孔建设修复试验工程，采用“乙醇+葡萄糖”液态碳源和“聚乙烯醇+淀粉颗粒”固态反应器分别进行岩溶水硝酸盐污染原位修复试验。结果表明:浓度500 mg?L－1、1 000 mg?L－1的“乙醇+葡萄糖”反硝化溶液对硝酸盐浓度的降解率分别为6.45 %和21.52 %；单位长度组成材料“聚乙烯醇3 kg+淀粉颗粒3 kg”、“聚乙烯醇2 kg+淀粉颗粒4 kg”的两种反硝化固态反应器对硝酸盐浓度的降解率分为33.91%和34.96%。试验证明在裂隙型岩溶地区采用孔组方案进行地下水污染原位修复技术可行、且能取得较显著效果。修复工程布设方式和试验成果对类似地区开展岩溶地下水污染原位修复具一定借鉴意义。   相似文献   

渤海湾盆地东濮凹陷古近系古湖盆氧化还原条件及其优质烃源岩的发育模式     

马小祥  姚素平  张柏林  张云献  彭君 《高校地质学报》2019,25(6):801

通过分析东濮凹陷古近系沙河街组烃源岩样品的主微量元素含量，研究了东濮凹陷沙河街组优质烃源岩形成时的古氧化还原条件、古生产力水平及古水体的局限性，探讨了沙河街组沙三段优质烃源岩的发育模式。研究结果表明，东濮凹陷的北部沙三段优质烃源岩发育属于“深水窄盆水体分层沉积”模式。水体主要是咸水—超咸水，水体局限性较强，深度较深形成了稳定的盐度分层，从而造成底层水处于稳定的缺氧条件，有利于有机质的保存。根据主微量元素分析及古生产力的还原，沙三段沉积时水体表层富氧，发育大量有机质，生物死亡后有机质发生絮凝，在氧化还原界面吸附于铁锰氧化物的表面，沉降到底部，底部水体缺氧到还原的性质，适合保存有机质。东濮凹陷南部沙三段优质烃源岩发育属于“浅水广盆凹盆缺氧沉积”模式。湖泊水体为淡水，湖水局限性很弱，属于开阔水域，由于地表河流及洪水带来大量营养物质，表层水体古生产力较高，缺乏缺氧的保存条件，有机质生化阶段消耗较多，但是局部也可以发育弱还原水体，进而形成优 质烃源岩。  相似文献   

The thermal maturity of sedimentary basins as revealed by magnetic mineralogy     

Mansour M. Abdelmalak  Stéphane Polteau 《Basin Research》2020,32(6):1510-1531

The thermal evolution of sedimentary basins is usually constrained by maturity data, which is interpreted from Rock-Eval pyrolysis and vitrinite reflectance analytical results on field or boreholes samples. However, some thermal evolution models may be inaccurate due to the use of elevated maturities measured in samples collected within an undetected metamorphic contact aureole surrounding a magmatic intrusion. In this context, we investigate the maturity and magnetic mineralogy of 16 claystone samples from Disko-Svartenhuk Basin, part of the SE Baffin Bay volcanic margin. Samples were collected within thermal contact metamorphic aureoles near magma intrusions, as well as equivalent reference samples not affected by intrusions. Rock-Eval pyrolysis (T_max), and vitrinite reflectance (Ro) analysis were performed to assess the thermal maturity, which lies in the oil window when 435°C ≤ T_max ≤ 470°C and 0.6%–0.7% ≤ Ro ≤ 1.3%. In addition, we performed low- (<300K) and high-temperature (>300K) investigations of isothermal remanent magnetization to assess the magnetic mineralogy of the selected samples. The maturity results (0.37% ≤ Ro ≤ 2%, 22°C ≤ T_max ≤ 604°C) show a predominance of immature to early mature Type III organic matter, but do not reliably identify the contact aureole when compared to the reference samples. The magnetic assemblage of the immature samples consists of iron sulphide (greigite), goethite and oxidized or non-stoichiometric magnetite. The magnetic assemblage of the early mature to mature samples consists of stoichiometric magnetite and fine-grained pyrrhotite (<1 μm). These results document the disappearance of the iron sulphide (greigite) and increase in content of magnetite during normal burial. On the other hand, magnetite is interpreted to be the dominant magnetic mineral inside the contact aureole surrounding dyke/sill intrusions where palaeotemperatures indicate mature to over-mature state. Interestingly, the iron sulphide (greigite) is still detected in the contact aureole where palaeotemperatures exceeded 130°C. Therefore, the magnetic mineralogy is a sensitive method that can characterize normal burial history, as well as identify hidden metamorphic contact aureoles where the iron sulphide greigite is present at temperatures beyond its stability field.  相似文献   

大洋地幔橄榄岩-铬铁矿中的金刚石和深地幔再循环     

杨经绥 《地质力学学报》2020,26(5):731-741

全球多地蛇绿岩型地幔橄榄岩和铬铁矿中发现微粒金刚石，并在中国西藏南部和俄罗斯乌拉尔北部的蛇绿岩铬铁矿中发现原位产出的金刚石，认为是地球上金刚石的一种新的产出类型，不同于金伯利岩型金刚石和超高压变质型金刚石。它们与呈斯石英假象的柯石英、高压相的铬铁矿和青松矿等高压矿物以及碳硅石和单质矿物等强还原矿物伴生，指示蛇绿岩中的这些矿物组合形成于深度150~300 km或者更深的地幔。金刚石具有很轻的C同位素组成（δ13C-18‰~-28‰），并出现多种含Mn矿物和壳源成分包裹体。研究认为它们曾是早期深俯冲的地壳物质，达到>300 km深部地幔或地幔过渡带后，经历了熔融并产生新的流体，后者在上升过程中结晶成新的超高压、强还原矿物组合，通过地幔对流或地幔柱作用被带回到浅部地幔，由此建立了一个俯冲物质深地幔再循环的新模式。蛇绿岩型地幔橄榄岩和铬铁矿中发现金刚石等深部矿物，质疑了蛇绿岩铬铁矿形成于浅部地幔的已有认识，引发了一系列新的科学问题，提出了新的研究方向。   相似文献   

Imaging the rupture process of the 10 January 2018 MW7.5 Swan island,Honduras earthquake*          下载免费PDF全文

Chuang Cheng  Dun Wang 《地震科学（英文版）》2020,33(4):194-200

The 10 January 2018 M_W7.5 Swan island, Honduras earthquake occurred on the Swan island fault, which is a transform plate boundary between the North American and Caribbean plates. Here we back-project the rupture process of the earthquake using dense seismic stations in Alaska, and find that the earthquake ruptured at least three faults (three stages) for a duration of ~40 s. The rupture speed for the longest fault (stage 3) is as fast as 5 km/s, which is much faster than the local shear wave velocity of ~4 km/s. Supershear rupture was incidentally observed on long and straight strike-slip faults. This study shows a supershear rupture that occured on a strike-slip fault with moderate length, implying that supershear rupture might commonly occur on large strike-slip earthquakes. The common occurrence of supershear rupture on strike-slip earthquakes will challenge present understanding of crack physics, as well as strong ground motion evaluation in earthquake engineering.  相似文献   

由下扬子区海陆对比分析南黄海盆地下志留统烃源岩特征及其主控因素     

蔡来星  肖国林  郭兴伟  王蛟  吴志强  李宝刚 《吉林大学学报(地球科学版)》2019,49(1):39-52

针对南黄海盆地海相油气勘探的重大需求，在收集、整理下扬子苏、浙、皖地区地质和地化资料的基础上，依托科学钻探CSDP-2井岩心，系统对比了南黄海盆地与下扬子陆区早志留世古地理背景和沉积充填特征，进而利用一系列地化测试数据总结了南黄海盆地下志留统烃源岩特征并探讨其主控因素。研究结果表明：南黄海盆地大陆架科学钻探CSDP-2井目前已钻遇了坟头组和高家边组上部两套丰度很低的厚层、暗色（粉砂质）泥岩，其有机质类型主要为Ⅱ₂型，热演化程度已整体进入过成熟阶段；受控于全球海侵事件和扬子板块构造活动的发展阶段，早志留世初期深水陆棚环境逐渐向后期的浅水陆棚环境演变，加之早期较高的初级生产力和良好的保存条件，使得下扬子区高家边组下部烃源岩的品质明显高于上部，并以底部黑色笔石页岩段有机质丰度最高。因此，南黄海盆地高家边组底部理应存在一套优质烃源岩层，可作为下一步页岩气勘探的重点层位。  相似文献   

高强耐热铝合金钻杆材料优选          下载免费PDF全文

梁健  尹浩  孙建华  李亚红  王成彪  张金昌 《探矿工程》2020,47(4):65-71

铝合金钻杆的使用性能是制约深部钻探技术发展的“瓶颈”。本文综合考虑孔内工况因素和钻杆性能因素，以钻柱组合设计为基础准则，从特深孔钻探工程技术需求出发，开展了高强耐温铝合金钻杆材质选择和评价的试验研究。试验结果表明：2219铝合金固溶时效制度分别为535 ℃/1 h、165 ℃/20 h，2618铝合金固溶时效制度分别为530 ℃/1 h、200 ℃/20 h；2219铝合金在高温长时间暴露后的室温力学性能优于2618铝合金，在高温瞬时条件下的力学性能劣于2618铝合金；2219铝合金中含有Zr，该元素在热暴露过程中起到减缓溶质扩散速率的作用，这对提高热暴露后的剩余强度是有利的。  相似文献