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对我国震旦纪、寒武纪磷块岩矿床的研究表明,参与成磷作用的生物主要是菌、藻类微生物。生物作用的标志表现为:P2O5主要富集在叠层石磷块岩中,富集在叠层石的柱体上,富集在柱体内部的富藻纹层中;而与磷块岩共生的白云石和黄铁矿的δ13C值和δ34S值相对均较低,则是生物参与成磷作用的同位素标志特点。生物的成磷作用贯穿成磷过程的始终,但它随作用的相带、环境和阶段不同,生物的种属和作用方式也不同,因而矿石和矿床的质量也随之而异。 相似文献
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瓮安地区埃迪卡拉系灯影组叠层石磷块岩是瓮安-福泉磷矿区新发现的含磷层位。磷块岩以典型的叠层石构造为主 要特征,呈透镜状生物礁（藻礁）形式产于灯影组顶部。叠层石磷块岩的矿物组成主要为磷酸盐矿物及碳酸盐矿物;白色 纹层富含磷酸盐矿物,而暗色纹层磷酸盐矿物含量较低,主要为碳酸盐矿物。通过对叠层石磷块岩矿物学及地球化学特征 进行研究,提出灯影组叠层石磷块岩属于潮下带半局限环境叠层石礁,是大量藻类通过生物或生物化学作用,将海水中磷 质富集-沉淀而形成磷质柱状叠层石礁;磷酸盐的矿化主要发生在沉积物-海水界面弱碱性次氧化环境,藻类在磷块岩形成 过程中起重要作用。 相似文献
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滇东下寒武统生物磷块岩的形成机制 总被引：3，自引：0，他引：3
显微结构研究表明,广泛分布于滇东地区下寒武统的磷块岩,除少量生物介壳磷块岩外,其它类型的磷块岩(包括菌藻生物磷块岩、内碎屑磷块岩和次生(风化)磷块岩等的颗粒均由磷质菌藻生物组成。从而揭示了菌藻生物磷块岩是磷块岩的基本类型。本文重点论述了生物磷块岩的结构成因分类、时空展布规律,以及滇东磷块岩的菌藻生物成磷—富磷作用,并探讨了菌藻生物磷块岩的形成机制。 相似文献
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叠层石是藻类等微生物作用而成的生物沉积构造。至今发现的现代叠层石都是碳酸盐的,而在地史中,除见到丰富的碳酸盐叠层石外,尚发现有大量磷质叠层石。中国南方震旦纪磷块岩,以及印度、苏联、澳大利亚、尼泊尔、西班牙、赞比亚等国前寒武纪及寒武纪磷块岩中的磷质叠层石,不仅是磷块岩的重要矿石类型,而且对判断磷块岩的沉积环境和探索藻类微生物对磷酸盐的聚集和富化都具有十分重要的意义。 相似文献
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黔中晚震旦世微生物岩及其磷的富集 总被引：1，自引：0，他引：1
我国南方晚震旦世广泛发育有包括叠层石、层纹石和核形石等组成的微生物岩, 其中以叠层石最为普遍; 黔中地区的磷质叠层石总体上以层礁产出为特点, 其中的藻类微生物化石已被确定的有丝状和球状两大类共１７ 个种属, 而细菌微生物参与成岩成矿作用的证据也常能见到。微生物岩中的磷质主要富集在叠层石的柱体部位, 特别是富集在柱体的富藻纹层中; 从微生物的矿化特点看, 其成矿作用可分为直接的和间接的两种不同机制的类型。与同期形成的碳酸盐叠层石相比, 磷质叠层石, 无论在种类的多样性或发育程度上都显得丰富多彩得多, 这可能与磷质叠层石所处的有利环境, 特别是对营造叠层石的微生物的生长所需的富磷水介质环境密切相关。 相似文献
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对我国震旦纪、寒武纪磷块岩矿床的研究表明,参与成磷作用的生物主要是菌、藻类微生物。生物作用的标志表现为:P2O5主要富集在叠层石磷块岩中,富集在叠层石的柱体上,富集在柱体内部的富藻纹层中;而与磷块岩共生的白云石和黄铁矿的δ13C值和δ34S值相对均较低,则是生物参与成磷作用的同位素标志特点。生物的成磷作用贯穿成磷过程的始终,但它随作用的相带、环境和阶段不同,生物的种属和作用方式也不同,因而矿石和矿床的质量也随之而异。 相似文献
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湖北震旦系磷块岩中的藻类化石 总被引：2，自引：0，他引：2
湖北荆襄地区震旦系陡山沱组磷块岩特别发育,含丰富的藻类化石。陡山沱组有四层磷块岩,第一层含叠层石和核形石,第三、四层含核形石。叠层石柱体被磷酸岩紧密包裹者,品位较高;基本层理由磷灰石与白云石交替组成亮层和暗层者,品位较低;柱体中仅含团粒状磷灰石者,品位更低。 相似文献
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通过对贵州织金稀土磷矿中高品位磷质条带和白云质条带两类矿石的工艺矿物学研究,查明了矿石的矿物组成、稀土元素和微量元素的赋存特性等,着重研究在不同粒级下的不同化学组分的分布情况、富集规律及相互关系,从降Si、Mg、Fe角度考虑,为原矿的破碎工序和选矿方案选择提供依据。研究结果表明,磷质条带属于高品位钙镁质磷块岩,P2O5平均品位为35%,w(MgO)平均为1.37%,w(SiO2)平均为5.76%,磷灰石是主要的有用矿物,含量为74.95%,与白云石、石英、方解石、黄铁矿等矿石紧密镶嵌共生;白云质条带其P2O5品位平均为8.35%,Mg含量相对较高,w(MgO)平均为14.58%,w(SiO2)平均为8.12%,白云质条带属于低品位钙镁质磷块岩,磷灰石是主要的有用矿物,含量22.99%,这种互层型磷块岩的主要脉石矿物有白云石、石英、黄铁矿等。 相似文献
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灯影组磷块岩有四种类型,即泥晶磷块岩、内碎屑磷块岩、藻磷块岩和细晶磷块岩。组成磷块岩的主要矿物是磷灰石、白云石、石英和少量伊利石等。磷块岩主要沉积在陆缘海内,它的沉积环境是与深水有联系的浅水地区。深水和浅水环境的地质背景分别为构造拗陷和碳酸盐岩台地。前者提供成矿物质,后者提供有利于磷质成矿的沉积环境。 相似文献
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贵州开阳以东磷矿整装勘查区位处扬子陆块东南边缘,是中国富磷矿最集中分布区。通过对开阳磷矿沉积学、岩石学、地层学和古地理学综合研究认为,开阳地区磷矿成矿受黔中古陆长期剥蚀夷平形成的无障壁海岸的海滩环境控制,高品位磷块岩矿石岩相组合特征、矿物学特征和沉积规律指示了开阳磷矿动态“三阶段成矿作用”过程(即原始生物—化学成磷作用、波浪簸选(机械)成矿作用和暴露淋滤成矿作用),波浪簸选成矿作用是形成厚度大、品位高富磷矿床的主导因素。按照“三位一体”成矿地质理论,确定了以沿黔中古陆北缘开阔海滩相层状展布的磷矿体展布特征,建立了区域成矿模式和地质找矿预测模型,并圈定临滨带为富磷矿重点预测靶区,开展找矿预测。通过产—学—研联合攻关,实现了磷矿理论创新,突破了该区原有磷矿找矿理论瓶颈,成矿范围从250km2增至1000km2,预测资源量从0.9442×108t增至13×108t。通过部分区块的工程验证,获得估算磷矿资源量(推断量+预测量)5.4892×108t,尤其新增富磷矿3.57×108t,取得中国富磷矿找矿重大突破。 相似文献
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Enrichment mechanism of phosphorite deposits and significant breakthrough in “Triunity Model”for ore prospecting in the Sinian Doushantuo Formation of eastern Kaiyang region,Guizhou Province 
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下载免费PDF全文 Liu Jian-Zhong Wang Ze-Peng Du Yuan-Sheng Zhang Ya-Guan Wu Wen-Ming Chen Guo-Yong Fu Zhi-Kang Wan Da-Xue Wang Da-Fu Tan Dai-Wei 《古地理学报》1999,22(5):913-928
Package exploration area in the eastern Kaiyang region is located at the southeastern margin of the Yangtze block,which is the concentrated distribution area of high-grade phosphorite deposits in China. The comprehensive studies of sedimentology,petrology,stratigraphy and palaeogeography in Doushantuo phosphorite ore-bed of the Kaiyang region show that the phosphorite deposits were controlled by the open shallow coastal sedimentary environment formed by denudation and deplanation of the Central Guizhou Oldland. Phosphorite lithofacies associations,mineralogical features and sedimentary structures indicate that the phosphorites had experienced “three stages of mineralization process”in the Kaiyang region: The first pristine bio-chemical phosphogenesis stage,the second winnowing and reworking stage and the last exposure and leaching stage. The winnowing and reworking processes are the key mechanism to the formation of the thick and high-grade phosphorite. According to the “Triunity Model”metallogenic theory,the research team confirmed the bedded distribution along the open phosphatic shore in the north of the Qianzhong Oldland,constructed the metallogenic model and ore prospecting model,and determined that the shoreface is the major target area of high-grade phosphorite ore. The research team have achieved the innovation of phosphorite metallogenic theory and broke through the bottleneck of phosphorite deposits exploration by cooperating of industry-university-research,and the metallogenic range was expand from 250km2 to 1000km2 and quantity of predicted resources increased from 94.42megatons to 1.3 giga-tons. The prospection verification in the part of areas estimated the ore resources of phosphorite deposits(Inferred and predicted resources) of 548.92 megatons,especially the newly added high-grade phosphorites 357 megatons,achieving significant breakthrough of ore prediction of high-grade phosphorites in China. 相似文献
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Microbial processes in the Negev phosphorites (southern Israel) 总被引：3，自引：0，他引：3
ABSTRACT Microscopic and SEM observations indicate that cyanobacterial activity was important during the formation of the Campanian Negev phosphorites. One aspect of such activity is the development of phosphorites through the binding of phosphate particles. These sediments often demonstrate a conspicuous smooth cryptalgal lamination. The algal binder was fossilized as intertwined phosphatic sheaths that coat and seal off the phosphate grains. Different types of sheaths representing the remnants of an algal community were found. Thick apatite overgrowth commonly deforms the microbial fossils converting them into barely recognizable forms. Fabrication of phosphate particles is another aspect of the microbial activity. Phosphate algal coated grains are a common constituent of the Negev phosphorites. The algal coating consists of stacked phosphatic tubes and colonies of coccoid unicells with an apatite infilling. Fragmented phosphatic sheath bundles form another type of phosphate particle produced by algae. Obliteration of algal structures is common, resulting in undifferentiated groundmasses of cryptocrystalline apatite. The extremely close connection between microbial structures and phosphatization processes suggests cyanobacterial participation in phosphorus enrichment. 相似文献
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《Chemical Geology》2002,182(2-4):483-502
Detailed petrological, mineralogical, geochemical and radiogenic (U, Sr, Nd) and stable isotope (C, O, S) studies have been carried out on the Quaternary phosphorites of the continental margin off Chennai, southeast coast of India. These phosphorites are formed as a result of trapping and binding of sediments by microbial mats and are similar to phosphate stratiform stromatolites. Detrital and biogenic constituents enclosed in the phosphorites controlled the major and minor element composition. Except for Sr and U, the concentrations of most of the trace metals are lower than those in average shale and phosphorite. Middle rare earth element (MREE)-enriched patterns are the characteristic feature. The U–Th dating method indicates that the ages of the phosphorites are beyond 300,000 years. 87Sr/86Sr ratios of the phosphorites are higher than that of present-day seawater and εNd values are more negative than those of seawater of the Atlantic Ocean. Carbon isotope ratios are within the range expected for the oxic/suboxic zone but sulfur isotope ratios indicate suboxic conditions during phosphorite formation. These results imply that the benthic microbial mats thrived on the shallow shelf during the Quaternary low sea level conditions. Periodic or episodic sedimentation onto the mats led to their death. The bacteria associated with decaying microbial mats utilised phosphorus supplied by continental sources and rapidly precipitated phosphate. The availability of a high percentage of phosphorus in seawater seems to be an important controlling factor for the formation of phosphate stromatolites. The composition of these phosphorites differs from the modern phosphorites in upwelling regions, but are similar to Cambrian apatite stromatolites. These phosphorites provide evidence that the replicates of ancient phosphate stromatolites do exist in the Quaternary. 相似文献
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黔中陡山沱期磷块岩成因的系统研究 总被引：1，自引：0，他引：1
黔中成磷区是中国南方陡山沱成磷期磷块岩矿床的重要组成部分。包括瓮福、开阳两个大型磷块岩矿床和若干中小型磷矿床。本文从磷的来源、沉积和富集3个方面系统地揭示了该区磷块岩的成因。稀土元素分析表明,磷可能来自同期海底火山喷发物。海洋地球化学、生物化学及磷块岩的组构研究证明,藻类生物的吸收和固定作用是磷质沉积的主要途径。磷的富集的多阶段、多因素的,经历不同的富集阶段(或方式)形成不同的磷块岩类型。 相似文献
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震旦系陡山沱组沉积期形成的黔中开阳、瓮安富磷矿沉积区,矿石产量大、品位高,是国内外重要的磷矿资源产区。黔中磷矿主要分布于黔中古陆周缘的滨浅海环境中,矿石类型以碎屑状磷块岩为主,间夹原生泥晶磷块岩、生物结构磷块岩和次生土状结构磷块岩。开阳式高品位磷块岩的动态沉积成矿过程通常为“三阶段成矿”: 第一阶段为初始成磷作用阶段,在新元古代大规模成磷背景下,上升洋流携带深部富磷海水进入滨浅海地区,并通过生物化学作用使磷质聚集并形成原生磷块岩沉积;第二阶段为簸选成矿作用阶段,高能波浪、风暴水流对原生磷块岩持续的破碎、磨蚀、搬运和再沉积过程中,簸选去除了原生沉积物中的陆源细碎屑、砂泥质成分,保留并聚集磷质碎屑颗粒,形成品位较高的碎屑状矿石;第三阶段为淋滤作用阶段,海平面升降变化使之前形成矿石受暴露事件影响,遭受强烈的风化淋滤作用,碎屑状磷矿石内的碳酸盐岩胶结物和白云石条带被淋滤运移,导致矿层发育大量溶蚀孔洞,甚至形成土状磷块岩,矿石品位再次得到大幅度提升。三阶段成矿作用随古地理条件和海平面变化在沉积成岩过程中多期次、动态进行,最终形成工业价值极高的磷矿石。 相似文献
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本文根据野外调查和室内初步研究成果并结合有关地质资料,分析、讨论了荆襄陡山沱组含磷岩系的磷块岩类型、成因和沉积环境。通过分析可知,组成磷块岩的磷灰石有不同的形成方式;磷块岩沉积在海退旋回中粘土和硅质沉积向碳酸盐沉积的转变阶段;磷块岩矿床形成在陆缘海内与深水有联系的浅水地带。 矿区含磷岩系特征综合于图1。 相似文献
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鲕粒,豆粒磷块岩的显微结构和生成特点 总被引：4，自引：0，他引：4
晚震旦世陡山沱组和早寒武世渔户村组、辛集组磷矿中有各种鮞粒、豆粒磷块岩。豆粒、鮞粒内核的成分和结构复杂,有来自陆地的各种岩石砂屑、细砾,也有盆内沉积物破碎成的各种内碎屑。鮞粒、豆粒的壳层是同心纹层状磷灰石,它是内核在富磷海水扰动中逐层淀积而成。大部分豆粒、鮞粒在滨海高能浅水中与陆源砂、砾和岔内碎屑沉积在一起,少量鮞粒则沉积在滨外深水低能环境巾。豆粒、鮞粒和碎屑等沉积后又被不同物质胶结。 相似文献