共查询到18条相似文献，搜索用时 78 毫秒
1.
胶磷矿的矿物组成,主要是微碳—低碳磷灰石,及细晶磷灰石。而胶磷矿细微颗粒,经电镜观察鉴定,主要由磷酸盐化有机碎屑及藻席碎屑组成,早寒武世磷块岩的形成是生物学、沉积学、古地理—古构造等综合因素沉积作用的产物。 相似文献
2.
贵州织金含稀土磷矿床稀土元素赋存状态研究 总被引：6，自引：0，他引：6
利用等离子质谱仪ICP-MS、扫描电镜配合能谱分析、电子探针分析方法,研究了贵州织金含磷岩系剖面稀土含量变化。结果表明,剖面上稀土含量与磷灰石含量变化呈正相关关系,说明稀土主要赋存于磷灰石矿物中;利用扫描电镜、电子探针分析方法对生物碎屑、白云石和胶磷矿进行单矿物微量元素分析研究表明,胶磷矿中稀土含量最高,生物碎屑和白云石稀土含量较低,说明织金含稀土磷矿床稀土元素赋存状态是以类质同象的形式存在于胶磷矿中;利用稀土元素化学物相分析研究同样表明只有少量的稀土元素被磷块岩中粘土矿物所吸附,大量的稀土元素以类质同相形式存在于胶磷矿中。 相似文献
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泥晶磷块岩(micritic phosphorite)是磷块岩的主要类型之一。我国的磷块岩矿床也多有这种矿石。过去往往把组成泥晶磷块岩的磷酸盐矿物叫做胶磷矿(collophane)。扫描电镜、X-射线衍射等观察结果表明,胶磷矿实际上也是结晶质磷灰石,只是由于颗粒极其微小而已。由这种泥晶磷灰石组成的泥晶磷块岩也同样不像过去描述的那样单调,而是具有比较复杂的结构、构造。 相似文献
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滇池地区沉积磷块岩中胶磷矿矿物学特征及其研究意义 总被引：1，自引：0，他引：1
本文从物理性质、化学成分及其成因结构等方面,对云南滇池地区胶磷矿进行了矿物学特征研究。提出该区胶磷矿主要以三种形式赋存在磷块岩中。对不同矿石类型中胶磷矿做扫描电镜研究,得知胶磷矿主要由超微晶低碳氟磷灰石集合体、磷酸盐显微莓群以及纤维放射状磷灰石等构成。经化学分析、红外、晶胞参数测定,不同胶磷矿有一定差异,特别是碳和磷,经矿物学对比发现,反映随变质作用的加深,胶磷矿有向晶质氟磷灰石演化的趋势,脱碳作用表现明显。本区胶磷矿稀土元素含量不高,钇族较富,铈族较贫。球粒陨石标准化后为铈亏损型模式。 相似文献
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前震旦紀变质岩在辽东半岛地区分布极其广泛,几乎占基岩出露面积百分之五十。因此找寻变质磷矿床一直是有关部门密切注意的对象。到1964年为止,在辽东半岛前震旦紀变质岩系中虽已发现有磷矿化现象,但多为胶磷矿,尚未发现典型的变质磷矿床。根据邻区所发现的变质磷矿床资料,大部份矿床附近的伟晶岩中富含磷灰石,磷灰石与白云石密切共生而组成磷灰岩或磷灰石白云质大理岩。这些 相似文献
6.
通过较多的透射电镜、扫描电镜及Ｘ光衍射分析,证实了湘西地区过去所谓的“胶磷矿”是由一定晶形的结晶磷灰石所组成,描述了这一类型泥晶磷块岩的矿物成分及结构特征,划分了矿石自然类型,分析了矿床沉积环境 相似文献
7.
一、概述长期来广大岩矿工作者习惯把无一定外形、具有胶状裂纹,正低偏中突起,全消光显微晶质的磷酸盐称为胶磷矿,它是磷块岩的主要矿物成分。1912年前认为胶磷矿是一种非晶质的磷酸盐矿物。1912年劳埃采用伦琴射线研究矿物内部结构,发现胶磷矿是结晶的非均质体,内部质点排列遵循晶体所共有的空间格子规律。随着多种先进测试手段综合运用于这种结晶质磷酸盐矿物的研究中,对其认识日趋统一。目前普遍认为胶磷矿主要是由超微粒状碳氟磷灰石组成,我们研究了贵州福泉震旦纪磷质迭层石、四川峨嵋震旦纪砂屑磷块岩和安微凤台寒武纪砾屑磷块岩中的胶磷矿,得到了相同结论。 相似文献
8.
我国目前已知磷矿床中的磷矿石,大致可以分为两种类型:一为內生的和沉积变质的磷灰岩,一为沉积的磷块岩。矿石中的有用矿物,前者主要为結晶的磷灰石;后者主要为非品质或隐品质的胶磷矿,常与硅酸盐矿物或碳酸盐矿物形成胶結物。在可选性方面两类矿石有显著不同的特点。 相似文献
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Abstract Phosphorite, or guano, or insular phosphorite, commonly containing 10-35% P2O5, is one of the sources of phosphatic fertilizer. Taking the modern insular phosphorite on the Xisha Islands as an example, this paper discusses the ore-forming mechanism of phosphate and the important contribution made by animals to this process. The phosphorite occurs in the middle part of carbonate sand cays of coral reef surrounded by longshore sandbanks, which assumes a dish-shape. The surface of the cays is covered by unconsolidated guano. The phosphorite, yellowish brown to dark brown, is made up of thick-bedded sand and gravel cemented by collophanite; and partly replaced by carbonate apatite. The mechanism of mineralization is as follows: The average content of phosphorus in the sea water is only 0. 07 ppm, but through the sea food. chain concentration, phosphorus content may become higher. The phytoplanktons, as producers, suck up phosphorus out of sea water. The primary consumers, zooplanktons, obtain phosphorus by eating phytoplanktons, then they are followed by the second and third consumers. Sea birds living on fish, as the third consumers, concentrate and transport the phosphorus to the carbonate sand cays. Finally layers of guano are deposited under the arbores. Under the tropical climatic conditions with high temperature and plentiful rainfall, soluble matters are leached out of the guano and infiltrated into deeper horizon. In alkaline groundwater with pH greater than 7. 0, the phosphoritization takes place, bioclastics are cemented and replaced by collophanite or carbonate apatite. Finally, the phosphorus is fixed and phosphate formed. 相似文献
12.
A microfossil assemblage has been detected in phosphorite cherts from the Dengying and Meishucun Formations (610 Ma) of the Sinian System in Jinning County, Yunnan Province, southwest China.A unique type (mode) of microfossil preservation — collophanite or apatite, or even in rare cases, chert-replacement — is reported here for the first time.The size frequency statistics for the assemblage are consistent with the results obtained by Schopf. The assemblage includes 18 genera and 20 species, among which 4 genera and 10 species are new. The assemblage consists of solitary and colonial spheroidal cells and septate or non-septate filaments, mainly Cyanophyta, especially Chroococaceae, Oscillatoriaceae and Nostocaceae.The microfossils described are Bigeminococcus grandis n. sp., Myxococcoides kingii, Myxococcoides grandis, Palaeoanacystis vulgaris, Archaeophycus venustus n.g. et sp., Eomycetopsis robusta, Circulinema jinningense n.g. et sp., Circulinema muirae n.g. et sp., Cyanonema infliatum, Obruchevella parva, Oscillatoriopsis awramikii n. sp., Palaeolyngbya oehlerii n. sp., Palaeolyngbya spiralis n. sp., Palaeotubulus lamellosus n.g. et sp., Veteronostocale sp. 1, Veteronostocale sp. 2, Allantomorphus septatus n.g. et sp., Clonophycus vacus n. sp., Archaeotrichion contortum, Rhienonema antiquum, Micrhystridium setulerum and Protosphaeridium densum. 相似文献
13.
浙西寒武系底部黑色岩系含矿性和有用组分的赋存状态 总被引：9，自引：0，他引：9
通过对浙西寒武系底部黑色岩系分布区的区域地质和典型矿床的地质特征分析,阐述了黑色岩系的含矿性和伴生元素的赋存状态.黑色岩系的底部为厚度不等的磷块岩（结核）层,其上为金属层或石煤层,金属层的厚度与磷块岩的发育呈正相关,与石煤层的厚度呈负相关.在石煤层或其上部的碳质页岩中含黄铁矿层.石煤中伴生有钒、镍、钼、铜、铅、锌、铀、银和稀土元素,在部分地段可富集成矿.钒或以独立矿物存在,或以类质同象赋存在粘土矿物中;镍主要以独立矿物存在;钼主要与碳、硫、粘土一起呈钼硫化物胶状集合体,经热接触变质作用后形成辉钼矿;铀呈不均匀分散在胶磷矿和碳泥质中,呈类质同象或吸附状态存在;稀土元素主要呈类质同存在于胶磷矿中,部分呈吸附状态存在;铜、铅、锌主要以硫化物和硫砷化物等存在,多富集在金属层中. 相似文献
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Arkadiusz Przybyło Anna Pietranik Grzegorz Zieliński 《Chemie der Erde / Geochemistry》2022,82(2):125864
Apatite is a versatile mineral crystallizing at different stages of silicic magma evolution. Its composition may record that of magma, but could also be affected by interaction with fluids. The focus of this study is the well-recognized magma mingling process that was previously detected using plagioclase composition and in this study complementary record is sought in apatite. The apatite was analysed in two dioritic enclaves (primitive and hybrid) and host quartz monzonite, which is an igneous rock emplaced at ca. 340 Ma in mylonitized Góry Sowie gneisses (NE Bohemian Massif). The apatite was analysed in-situ by microprobe that allowed for chemical characterization of different apatite populations in quartz monzonite and analyses of thin acicular apatite in the enclaves. Apatite population in the quartz monzonite was chemically distinct from that in both enclave types and characterized by higher Y and lower Ce contents, such values are usually typical for peraluminous magmas. As such, the apatite transfer from felsic to mafic magma should be well recorded in apatite composition, which was not the case. Monzonite apatite composition was not commonly observed in the hybrid enclave despite massive plagioclase transfer and only rare resorbed cores with low Ce and Y contents were present. However, such low Ce and Y cores crystalized at the latest stage of apatite crystallization in the quartz monzonite, whereas the plagioclase transfer was an early episode. Therefore, we conclude that apatite transfer was limited during mingling and the apatite composition in the quartz monzonite is best explained by an early Cl-Ce-rich fluid removal and then fractional crystallization, while apatite in the primitive enclave is affected only by fractional crystallization. Altogether, Ce and Y composition of apatite is a valuable tool to record diverse magmatic processes such as fluid removal and precipitation from fluid in addition to fractionation of different REE phases and should be further explored. 相似文献
15.
磷灰石可以记录和保存岩浆和热液活动的信息。可可托海伟晶岩型稀有金属矿床磷灰石发育,为研究该矿床伟晶岩成岩成矿过程提供了优良的条件。已有对可可托海伟晶岩型稀有金属矿床磷灰石的研究集中在其稀土元素特征,较少讨论其对伟晶岩成岩成矿过程的制约。本文选取可可托海伟晶岩型稀有金属矿床富矿伟晶岩脉(3号脉)和相对贫矿伟晶岩脉(1号、2b号和3a号脉)中的磷灰石作为研究对象,进行磷灰石岩相学和地球化学研究。岩相学分析表明,磷灰石主要与钠长石、石英、白云母、锰铝榴石等伴生。EPMA分析显示,磷灰石F含量为3.67%～4.41%,Cl含量小于0.67%,较低的Cl含量表明伟晶岩熔体出溶的流体Cl含量较低;大部分磷灰石MnO含量为4.67%～8.71%,但2b号脉磷灰石MnO含量变化较大(1.23%～14.28%),这是由于2b号脉磷灰石具有分带结构,暗示其遭受后期热液作用,促使磷灰石溶解-再沉淀,导致MnO含量发生较大变化。LA-ICP-MS分析显示,贫矿伟晶岩脉磷灰石的稀土元素含量较低(180×10~(-6));相反,富矿伟晶岩脉磷灰石的稀土元素含量较高( 700×10~(-6)),并具有明显的四分组效应(TE_(1-3)平均值为1.7)。1号脉和3a号脉磷灰石均显示轻稀土元素富集,反映其形成过程中有含Cl热液的参与。3号脉磷灰石显示强烈Eu负异常和Ce正异常,而2b号脉磷灰石显示强烈Ce负异常和中等Eu负异常,这种Eu、Ce异常的差异可能与岩浆-热液阶段大量流体出溶密切相关。磷灰石的沉淀将导致热液中HF含量的降低,促使磷灰石周围铌钽矿结晶和Nb、Ta进入磷灰石中。可见,在伟晶岩形成过程中,磷灰石并非保持稳定,其分带结构和主微量成分变化记录了后期热液活动,暗示后期热液活动对伟晶岩的成矿具有重要作用。 相似文献
16.
X射线衍射分析和化学成分研究表明,磷灰石为氟磷灰石,榍石成分中存在着的主要类质同象替代是(Fe~(3+)、Al)+(F,OH)~-=Ti~(4+)+O~(2-)。磷灰石和榍石是碱性辉长岩的REE、Ba、Zr等微量元素的主要载体;它们是在较高氧逸度的条件下结晶的。磷灰石的Sr同位素特征说明形成双龙桥碱性辉长杂岩的物质来源于上地幔。 相似文献
17.
An evaluation of models of apatite compositional variability using apatite from the Middle Banded series of the Stillwater Complex,Montana 总被引：2，自引：0，他引：2
Apatite is a relatively common accessory mineral in the olivine-bearing zones (OB-III and OB-IV) of the Middle Banded series
of the Stillwater complex, occurring interstitial to cumulus grains, as monomineralic inclusions in cumulus grains, and in
polymineralic clusters which may or may not be included in the cumulus grains. Eighty-nine of 185 samples examined were found
to contain some apatite. The F-Cl-OH content of the apatite show distinct stratigraphic variations. XClAp (mole fraction Cl
in apatite) of interstitial apatite increases upsection in both OB-III and OB-IV with average values ranging from 0.15 to
0.85 in OB-III and from 0.03 to 0.60 in OB-IV. XFAp varies inversely with XClApwith average values ranging from 0.00 to 0.70, while XOHAp remains relatively constant near 0.40 or decreases slightly with
height. These variations are remarkable given that no appreciable stratigraphic variations in either the major or trace element
compositions of any of the cumulus minerals are found in the 800 m of section that comprise OB-III and OB-IV. Within-sample
variation of XClAp for samples containing Cl-rich apatite is substantially larger (up to 0.65 XClAp) than for samples with
more F-rich apatite (XClAp varies by approximately 0.15). Although interstitial apatite is found throughout OB-III and OB-IV,
apatite occurring as monomineralic inclusion in cumulus grains or in polymineralic clusters is almost exclusively found in
samples with Cl-rich apatite. The data are best explained by a model involving the degassing of a Cl-rich volatile phase from
the crystallizing interstitial liquid. The up-section migration of this fluid resulted in the crystallization of F-rich apatite
in the lower portion and progressive Cl-enrichment in the apatite with height. The presence of hornblende-bearing dikes, veins
and pegmatoids at the level of maximum Cl-enrichment is consistent with a fluid migration model.
Received: 5 October 1995 / Accepted: 19 March 1996 相似文献