冀西北黄土梁金矿控矿因素分析     

刘海田 《地质与资源》1999,8(4):209-216

河北省赤城县黄土梁金矿产于水泉沟-大南山碱性杂岩体内接触带,矿床受钾化正长岩及断裂构造双重控制.矿床具矿化带宽、规模大、贫硫化物、蚀变单一、矿石类型简单、埋藏浅、易采选等特点,是一处与海西期-燕山早期岩浆活动有关的热液矿床.  相似文献   

Origin and U–Pb dating of zircon-bearing nepheline syenite xenoliths preserved in basaltic tephra (Massif Central, France)     

Jean-Louis Paquette  Juliette Mergoil-Daniel 《Contributions to Mineralogy and Petrology》2009,158(2):245-262

Zircon-bearing xenoliths in continental basalts are often interpreted as witnesses of the continental basement uplifted during volcanic eruptions. Nevertheless, their origin is still debated. The Devès basaltic plateau belongs to the alkaline volcanic province of the French Massif Central. In few outcrops, zircon-bearing nepheline syenite xenoliths were preserved. U–Pb dating of the zircon crystals define an age of 956 ± 11 kyr constraining the crystallisation time of the zircons and consequently of the host xenoliths. This age, together with mineral chemistry arguments lead us to conclude that these minerals do not derive from a continental protolith. Rather, they likely result from the crystallisation of a liquid characterised by a nepheline–felspar composition and produced by the differentiation of a basaltic magma or, alternatively, by the low degree partial melting of a metasomatised lithospheric mantle. Such alkaline sialic rock and xenoliths may occur in large volumes at depth and generate the large amounts of zircon megacrysts discovered worldwide in secondary deposits within continental basaltic provinces.  相似文献   

霓辉正长岩制取铝酸钠溶液预脱硅的实验研究     

王霞  马鸿文  俞子俭  王晓艳  邹丹 《现代地质》2011,25(1):157-162

霓辉正长岩提钾滤渣的主要物相为沸石Na6[AlSiO4]6.4H2O,富含氧化铝和氧化硅。采用高压水化学法对其进行碱热浸取可得到高苛性比的铝酸钠溶液,通过添加不同类型的脱硅剂对其进行一步脱硅法对比实验研究。正交实验结果表明,在脱硅的过程中,影响因素的顺序为:脱硅剂类型>脱硅时间>脱硅温度。通过进一步单因素实验,确定优化脱硅条件为:采用水合铝酸钙为脱硅剂,在160℃下反应3.5 h,即可制得硅量指数大于1 800的铝酸钠精制液。经X射线衍射分析,脱硅产物的主要物相为水化石榴石;扫描电镜及能谱分析结果显示,生成物水化石榴石的晶型较好,在晶粒细小处S iO2杂质容易附着,从而达到更好的脱硅效果。  相似文献   

岩石标准物质的研制     

(Institute of Rock  Mineral Analysis  Ministry of geology  mineral Resources  Beijing 《岩矿测试》1995,14(2):114-161

研制了霓霞正长岩，粗面岩，花岗闪长岩，辉长石，流纹岩及白云岩６种不同类型的岩石标准物质，对用Ｘ射线荧光光谱均匀性检验实际取样量进行了探讨，选择分析测试方法时，除采用了标准方法和长期应用的分析方法外，还采用了近年发展起来的新技术新方法，在定值中应用了多参数统计定值模式，给出了６９个元素的标准值和参考值，该批标准物质于１９９１年１月经国家技术监督局审核批准为国家一级标准物质，编号分别为ＧＢＷ０７１０９  相似文献   

中国霞石正长岩的地质特征          下载免费PDF全文

黄强  邸素梅 《地质找矿论丛》2001,16(1):67-72

介绍了中国霞石正长岩的分布，产出的大地构造环境，岩体的岩石组合，岩石的地球化学和造岩矿物组合特征，论述了主要造岩矿物的矿物学特征及产出母岩的关系，以及工业岩石对霞石正长岩的一些指标要求。  相似文献   

The Thermal History of the Huangmeijian Granite Intrusion in Anhiii and Its Relation to Mineralization: Isotopic Evidence     

Zheng Yongfei  Fu Bin  Gong Bing 《《地质学报》英文版》1996,9(2):168-180

Abstract Whole—rock Rb—Sr, zircon U—Pb and hornblende, biotite and K—feldspar K—Ar ages are used to reconstruct the cooling history of the Huangmeijian intrusion in the Anqing—Lujiang quartz—syenite belt in Anhui. Oxygen isotope geothermometry of mineral pairs demonstrates that diffusion is a dominant factor controlling the closure of isotopic systems. Assuming the cooling of the intrusion is synchronous with a dicrease in local geothermal gradients, an emplacement depth of about 8 km and the magma crystallization temperature of 800 ± 50°C are estimated. The Huangmeijian intrusion experienced a rapid cooling process and uplifted after its emplacement and crystallization at 133 Ma B.P. with a cooling rate of 34.5°C / Ma and an uplifting rate of 0.35 mm/ a. The intrusion was rising until it rested at a depth of 3 km at a temperature of 300 ± 50°C about 14 Ma later. Then the intrusion was in slow cooling and uplifting with a cooling rate of 4.4°C / Ma and an uplifting rate of 0.04 mm/ a. U—Pb dating of pitchblende is done for the hydrothermal uranium deposit formed in the contact zone of the Huangmeijian intrusion. The result shows that the mineralization age is close to the closing time of the K—Ar system in biotite. The fluid inclusion thermometry indicates that the mineralization temperature is in agreement with the closure temperature of the biotite K—Ar system. This suggests a close relationship between the slow cooling of the intrusion and the hydrothermal uranium mineralization process.  相似文献   

湖北观子山硬玉钙霞正长岩初步研究   总被引：2，自引：0，他引：2  

李石 《岩石矿物学杂志》1990,9(1):22-30

观子山侵入体从岩体中心到边部，由硬玉钙霞正长岩、硬玉正长岩和黑云角闪正长岩组成。本文着重讨论硬玉钙霞正长岩的岩石学、矿物学、岩石化学、REE的地球化学、时代及岩石成因。据Rb-Sr等时线测定，其年令值为306Ma，说明它形成于海西期。根据产状、FeO/MgO,^δSr/^δSr（i）、REE分配模式以及形成硬玉的压力温度条件，足以证明硬玉钙霞正长岩的成因与上地幔物质有关。  相似文献   

安庐石英正长岩带的地质和地球化学特征及成因探讨   总被引：10，自引：4，他引：10  

章邦桐  张富生  倪琦生  陈培荣  翟建平  沈渭洲 《岩石学报》1988,4(3)

安庐石英正长岩带由黄梅尖、城山、大龙山三个多阶段复式岩体组成,其形成与郯庐断裂带在中生代末发展演化成陆内裂谷的事件有关。岩带的成岩物质来源较深,是地幔分熔产生的安粗岩浆,在其上升侵位过程中经受上部地壳物质混染,为幔壳混源成因,其中地幔组分约占60.2—53.8％,地壳组分约占39.8—46.2％。岩带中的岩石偏碱性、贫水和非造山等一系列地质地球化学特征可与A型花岗岩相类比。  相似文献   

Luku Alkali Syenite in the Hongge Ore District, SW China: Geochemistry, Geochronology and Metallogenic Significance     

ZHOU Jiayun  LIU Yingdong  XU Li  ZHU Zhimin  GONG Daxing  JIANG Xiaoli 《《地质学报》英文版》2022,96(3):875-890

Luku alkali syenite is distributed throughout the southern end of the Hongge basic-ultrabasic intrusion in Panzhihua, Sichuan, SW China. Using LA-ICP-MS, the alkali syenite intrusion yielded a zircon U-Pb age of 264.5 ± 1.6 Ma, concordant with the ages of the E’meishan large igneous province (260 Ma). The intrusion displayed silica-saturated, Al-adequate and alkali-rich signatures, with SiO2 62.07%–64.04%, Al2O3 16.26%–16.79% and Na2O + K2O 9.17%–9.91% (averaging 9.31%). The rock falls into the alkaline zone on the SiO2-A.R. diagram, as well as in the potassium zone on the K2O-Na2O diagram, indicating a potassium alkaline rock. The rock has a low total REE concentration and showed enrichment in LREE (LREE/HREE = 7.06–7.95), typical negative Eu anomalies (δEu = 0.73–0.80), trace element deficiencies in LILEs (Ba, K, Sr, Zr) and enrichment in HFSEs (Th, U, Nd, Sm, Ta and Nb), displaying crust and mantle element information. Zircons show a strong positive Ce anomaly and negative Eu anomaly, similar to the characteristics of crustal source magmatic zircon, however the (Lu/Gd)N ratio ranges from 1.48 to 3.17, and the (Yb/Sm)N ratio ranges from 38.49 to 77.15, which are similar to the characteristics of mantle-derived magmatic zircon. In the La/Yb-δEu correlation diagram, the data plots near the boundary between crust type and crust-mantle type. From the combined ‘trinity’ spatiotemporal relationship of Indosinian intermediate-acid alkali intrusive rocks in the Panxi area with E’meishan basalt and basic-ultrabasic intrusive rocks, the regional tectonic evolution and the partial melting model of the most intraplate magma sources, we believe that the Luku alkali syenite in Sichuan was formed from the partial melting of a crust-mantle source material, due to underplating of the mantle plume basic magma.  相似文献   

滇东南长安金矿晚始新世正长斑岩岩石地球化学、成岩时代及其地质意义     

张垚垚  陈宣华  张达  莫宣学  邵兆刚  赵泽南  李兴俭 《地球学报》2022,43(6):817-831

滇东南长安金矿位于哀牢山造山带的南段, 矿区内主要出露的岩浆岩为正长斑岩, 常与金矿体伴生, 其形成时代及岩浆演化对长安金矿研究具有重要指示意义。本文选取正长斑岩样品进行岩石学、地球化学、锆石U-Pb和Hf同位素研究。研究表明, 正长斑岩SiO2含量为68.00%~70.43%, 全碱含量(K2O+Na2O)8.15%~8.76%, 属于亚碱性系列强过铝质岩石, 具S型花岗岩特征, ΣREE为71.52×10–6~76.43×10–6, 含量较低, 轻重稀土分异程度较大, 稀土配分曲线具右倾特征, 具δEu弱负异常(0.81~0.86)和δCe弱正异常(1.15~1.33), 微量元素蛛网图具右倾特征, Rb、Ba、Th、K等大离子亲石元素相对富集、高场强元素相对亏损, 具Nb、Ta负异常特征。岩体锆石发育震荡环带, Th/U比值较高, 锆石206Pb/238U分析点呈点群分布, 加权平均值为(34.7±0.3) Ma, 表明岩体形成于始新世晚期。锆石εHf(t)为–2.65~2.02, Hf单阶段模式年龄(TDM)为629.95~821.54 Ma, 二阶段模式年龄(TDMC)为1 378.52~1 801.25 Ma, 表明岩体主要由古老地壳成分部分重融形成, 混杂有少量幔源物质。岩石具埃达克岩特征, 形成于后碰撞构造背景。  相似文献