加拿大萨斯喀彻温海相钾盐矿床特征及钾矿勘探开发研究

发布时间：2018-03-17 02:00

本文选题：萨斯喀彻温　切入点：麋鹿点　出处：《中国矿业大学(北京)》2017年博士论文　论文类型：学位论文

【摘要】：钾肥是农业氮磷钾三大肥料之一,世界上约95%钾盐用作钾肥。经过多年的勘探工作,目前我国钾盐经济可采储量已经由几年前的7000万吨提升到了现在的1.4亿吨。但作为世界钾盐主要的消费市场之一,中国的钾肥对外依存度依旧很大,仍需采取措施积极保障钾肥供应和价格长期稳定。世界钾矿资源分布依旧相对集中,少数国家占有绝大多数的资源。加拿大萨斯喀彻温省麋鹿点(Elk Point)盆地中的钾盐矿床是世界上最大的钾盐矿床,以规模大、矿层厚、品位高、有害杂质少著称。该钾盐矿床位于麋鹿点盆地中的萨斯喀彻温次盆地。本文以加拿大萨斯喀彻温省麋鹿点盆地内钾盐矿床为研究对象,对中川国际矿业控股有限公司位于该盆地的‘中钾’项目(KP488矿区)的86.6km二维地震测线,96km2三维地震,7个钻孔(钻探总进尺9722.7m)和1382件岩心化学分析样进行深入研究,结合笔者参与该项目八年的工作经验和大量周边区域地质资料,对该钾盐矿床构造、成因、特征进行总结;通过将萨斯喀彻温钾盐矿床成因与世界其他主要海相钾盐矿床比较,归纳海相钾盐成矿规律,为勘查海相钾盐提供参考;对钾盐矿床深部勘探提出优化勘探方法;总结海外矿业开发需注意事项,为我国资源矿业企业‘走出去’提供参考。麋鹿点盆地矿床特征研究显示,多次海侵—海退旋回,多级海盆的构造,欠补偿的的海相地台型盆地构造都是形成萨斯喀彻温海相钾盐矿床的条件。而多次海侵—海退旋回和多级海盆形成于古赤道的地理位置变化和古气候的周期变化密切有关。古地理和古气候的变化促使在多级海盆中几个次盆地沉积大量盐堆积后,最后在几种因素共同耦合下,钾盐在萨斯喀彻温次盆地形成沉积。萨斯喀彻温钾盐矿床是构造、古地理、古气候多种作用共同耦合的结果。区域上,盆地发展有两个沉积-构造阶段,初始的被动大陆边缘(寒武纪至中侏罗纪)阶段,萨斯喀彻温地区沉积了特征的底部碎屑单元、其上很厚的碳酸岩与蒸发岩。其后是聚合边缘阶段(中侏罗纪至始新世),形成前陆盆地,隆起的卡迪拉尔山系(Cordilleran Mountain Belt)提供了大量碎屑,形成厚的碎屑堆积。北美大陆以地盾—克拉通为中心,环带状分布显生宙造山带。加拿大地盾是北美大陆的核心,而在加拿大地盾外围,北美中部地台上形成了大平原,科罗拉多高原和哈德逊湾。地盾、地台和基底一起构成北美克拉通。萨斯喀彻温省钾盐矿床是在稳定的克拉通盆地上发育的海相蒸发岩矿床。其东北部为加拿大地盾,是极稳定地质构造,西部为加拿大沉积盆地,泥盆纪时北美地台开始下降,海面上升,海水自西北进入麋鹿点盆地,海侵自西北向东南呈螺旋式发展,有多个海侵—海退旋回,经过多级海盆的数次沉积和迁移,最终形成了巨型海相钾盐矿床。麋鹿点盆地周围构造都处于稳定区,而自盆地东北部进入的海侵与几个次级盆地的迁移运动为不稳定状态,其钾盐形成于构造稳定区中的相对不稳定或亚稳定区。世界海相钾盐形成的有利区域多为稳定构造中的相对活动区盆地构造。所以,海相钾盐形成的有利构造为:在大的构造稳定区内,海相钾盐沉积容易形成于相对活动的亚稳定区中;而在大的构造亚稳定区内,海相钾盐沉积则容易形成在相对稳定区中(基底为地核或原地台)。海相钾盐成因研究,对我国海相钾盐找矿有积极意义。通过对KP488矿区7个钻孔地层层序的分析,与周围区域地层层序对比,将萨斯喀彻温次盆地中-上泥盆统划分为四个成盐旋回,钾盐仅分布于第一旋回的中泥盆统麋鹿点群中的“草原蒸发岩”组顶部约60m范围内。成盐旋回的划分可为海相钾盐找矿提供一些线索。萨斯喀彻温省钾盐矿床中常出现盐溶、塌陷、下覆Winnipegosis礁等异常构造。通过地震和钻井资料对比,根据塌陷影响范围、厚度、结构将盐溶塌陷分为4级,在钾盐勘探开发中可更清晰标识异常区域。Winnipegosis礁大概率造成上覆草原蒸发岩层的减薄,但研究表明,钾盐层位于草原蒸发岩的上部,其形成和沉积形态受Winnipegosis礁上凸的影响较小。草原蒸发岩层的塌陷和溶蚀更多是受局部构造变化和地下水溶蚀影响,Manitoba群Souris River组的Davidson蒸发岩在沉积序列中与草原蒸发岩靠近。Davidson石盐层在钾盐勘探中可作为一个探矿标志,帮助判断该地区的是否有地下水及溶蚀情况,若Davidson石盐层连续且完整,则可推测该区域的钾盐赋存情况良好,出现盐溶的几率较小。通过对KP488矿区地震物探资料、7个钻孔的岩心化验分析、测井资料进行分析研究,显示该区域蕴藏高品位钾盐层Paticence Lake和Belle Plaine。与萨斯喀彻温省在产钾矿比较,其矿石品质相近,埋深更深,地层层序和沉积情况也萨斯喀彻温省在产钾矿相近,进一步拓展了萨斯喀彻温省钾盐沉积的埋藏范围及赋存连续性。盐类矿床勘查多以地表取样和打钻为主要手段,但对于埋藏深的海相钾盐矿床,这套方法找矿效率较低且成本高。由于地震技术和测井分析的技术进步,本文提出深度钾盐矿床找矿方法:以二维、三维地震为主,钻探为辅,同时对历史钻孔进行测井,从而高效率低成本完成海相钾盐深部找矿工作。北美地质评价体系与中国不同,本文中概略归纳了北美地质评价体系,可与我国地质评价体系相比较,增强中外地质评价体系互通。本文作者参与“中钾”项目八年的工作,从最初勘查到取得矿权,再到勘探开发。对该项目第一手资料的掌握和研究,以及对加拿大萨斯喀彻温省当地钾矿成因、地质、开发的资料的整理与研究,对矿藏产状、塌陷特征、地震勘查等这些最新的资料的整理总结,望能为我国钾盐勘查开发提供一些参考。通过剖析该项目及中资企业在海外钾盐投资开发的其他钾盐项目,总结优势和不足,探讨在海外开发建设钾矿的合理方式,使本文选题研究成果具有重要的社会和经济意义,对中国企业建立海外钾盐基地,保障中国钾盐供给有参考利用价值。
[Abstract]:Potassium is one of the three major agricultural NPK fertilizer, potash potash for about 95% of the world. After years of exploration, China's potash economic recoverable reserves have a few years ago 70 million tons to 1.4 tons. But now as the world's major consumer market of potash, potash China external dependence the degree is still great, still need to take measures to actively protect the potash supply and price stability. The long-term distribution of world potash resources is still relatively concentrated in a few countries, occupies most of the resources. The Canadian province of Saskatchewan elk point (Elk Point) in the potash deposit basin the largest potash deposits in the world, with a large scale, seam thickness, grade high, less harmful impurities known. The potash deposit is located in Texas Kachewenci basin elk point basin. The Saskatchewan potash deposit in the elk point basin as the research on As for Zijin Mining Group Co. Ltd. is located in the basin of the 'k' project (KP488 mine) 86.6km two-dimensional seismic lines, 96km2 3D seismic, 7 boreholes (total drilling footage of 9722.7m) and 1382 core samples for chemical analysis in-depth study, combined with eight years working experience in the participation of the project a large number of peripheral and regional geological data, the formation of the potash deposit structure, this paper summarizes the features of; by comparing the Saskatchewan potash deposit formation and other major marine potash deposit, summarizes metallogenic regularity of marine potash exploration, to provide reference for marine potash; optimize exploration method for deep prospecting potash deposit; summarize the overseas mining development needs note, for China's mining enterprises' resources to provide the reference. The study "out of the feature point basin elk showed multiple transgressive regressive cycles, multi-stage basin structure, owe The platform type marine basin compensation are the formation of Saskatchewan potash deposits in the sea phase conditions. Closely related to periodic variation of multiple transgressive regressive cycles and multi-stage basin formed in the change of ancient equatorial location and paleo climate. Palaeogeographic and palaeoclimatic change prompted several times a lot of salt deposition basin in multistage accumulation after the last in the basin, coupled with several factors, the formation of potash deposits in the Texas Kachewenci basin. Saskatchewan potash deposit is tectonic paleogeography, paleoclimate various interaction coupling results. The region, there are two stages of tectonic sedimentary basin, the passive continental margin (initial Cambrian to Jurassic) stage, Saskatchewan sedimentary bottom clastic unit characteristic, the thick carbonate and evaporite. Followed by polymerization stage (in the edge of Jurassic to Eocene), shape A foreland basin, mountain uplift derar card (Cordilleran Mountain Belt) provides a lot of debris, forming thick debris. The North American continent to shield and craton as the center ring distribution of Phanerozoic orogenic belt. The Canadian Shield is the core of the North American continent, and in the Canadian Shield outside of North America formed on the central platform the Great Plains, Colorado plateau and Hudson Bay. The shield, platform and base together to form the North American craton. Saskatchewan potash deposit is marine evaporite deposit developed in craton basin. The northeast of the Canadian Shield, is extremely stable geological structure, the western Canada sedimentary basin, the North American platform began to decline the sea level rise, sea water, from the northwest into the elk point basin, transgression from the northwest to the southeast is the spiral development, there are a number of transgressive regressive cycles through the multi-stage Basin The deposition and migration of several times, and eventually formed a giant marine potash deposit. Around the structure of the elk point basin in the stable region, and the migration of self in the northeastern basin into several sub basins of transgression and is not stable, the potassium salt formed in the tectonic stability region is relatively unstable or metastable zone. The favorable regions of the world marine potassium salts are the relatively stable tectonic activity area structure. Therefore, favorable structure for the formation of marine potash in large area tectonically stable, sub stable region marine potash deposits formed in the relatively easy activities; in the large tectonic sub stable area, is easily formed in marine potash deposits the relatively stable region (base for core or protoplatform). Research on the causes of China's potash marine, marine potash prospecting has positive significance. Based on the analysis of the KP488 mine 7 borehole stratigraphic sequence, and the surrounding area Correlation of sequence stratigraphy, the Texas Kachewenci basin in the upper Devonian is divided into four cycles of salt, potassium salt is only distributed in the first cycle of the Middle Devonian elk point group in the "prairie evaporite group" at the top of the range of 60m. Approximately divided into salt cycle can provide some clues for marine potash prospecting. Saskatchewan potash deposits often appear in salt solution, collapse, the overlying Winnipegosis reef anomalous structure. By comparing the seismic and drilling data, according to the effect of subsidence range, thickness, the structure will collapse in salt solution is divided into 4 levels, can be more clearly identified abnormal regions of reef.Winnipegosis probability of overlying strata caused by grassland evaporation reduction thin in the exploration and development of sylvite, but research shows that potash evaporite upper layer is located in the grassland, its shape is affected by the formation and deposition of Winnipegosis reef convex small. Prairie evaporite strata collapse and erosion is more affected by local The structure change and groundwater dissolution effect, Davidson group Manitoba Souris group River evaporite rocks in sedimentary sequence and prairie evaporite near.Davidson halite layer can be used as a prospecting sign in potash exploration in the region, to help determine whether there is water and dissolved, if Davidson halite layer is continuous and complete, it is presumed that the occurrence of potash the area is good, appear less likely to salt. Based on KP488 mining seismic geophysical data, analysis of 7 drilling core test, analysis of well logging data, the display area contains the high grade potassium Paticence Lake and Belle Plaine. layer and Saskatchewan in the production of potassium ore, the ore quality similar to the depth of burial. Deep stratigraphic sequence and sedimentary conditions in Saskatchewan potash production is similar, to further expand the scope and buried Fu Cunlian Saskatchewan potash deposit Continued. Salt deposit exploration on surface sampling and drilling as the main means, but for the marine potash deposit buried deep ore prospecting, this method is of low efficiency and high cost. The analysis of seismic and logging technology progress, this depth of potash deposit prospecting method based on the two-dimensional, three-dimensional seismic. At the same time for logging drilling by historical drilling, high efficiency and low cost so as to complete the deep marine potash prospecting work. Different geological evaluation system of North America and Chinese, this paper briefly summarizes the geological evaluation system of North America, can be compared with the system of geological evaluation in China, strengthen interoperability geological evaluation system both at home and abroad. The author participates in "K" eight years of work, the acquisition of mining rights from the initial exploration, to the exploration and development. On the first hand data of the project control and research, as well as the Saskatchewan Canada when potassium ore genesis, Geology, arrangement and Research on the development of the information, the collapse characteristics of mineral exploration, earthquake occurrence, the latest data summary, hope to provide some reference for the exploration and development of our country. Through the analysis of the project, and Chinese enterprises in overseas investment in the development of the potash potash project, summarizes the advantages and disadvantages to explore the reasonable way of overseas development, in the construction of potash, so this topic research has important social and economic significance, the establishment of overseas potash base on China enterprises, security China potassium supply reference value in use.

【学位授予单位】：中国矿业大学(北京)
【学位级别】：博士
【学位授予年份】：2017
【分类号】：P619.211

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