Statistical evaluation of the geochemical data for prospecting polymetallic mineralization in the Suoi Thau – Sang Than region, Northeast Vietnam

In Northeast Vietnam, Suoi Thau-Sang Than is considered as a high potential area of polymetallic deposits. 1,720 geochemical samples were used to investigate polymetallic mineralization; thereby polymetallic ore occurrences in this study region were discovered and the statistical and multivariate analysis helps to define geochemical anomalies in some northeastern regions, namely Suoi Thau, Sang Than, and Ban Kep. The statistical method and cluster analysis of geochemical data indicate that the Cu, Pb, and Zn elements are good indicators, and most of them comply with the lognormal or gamma distribution. Based on the third-order threshold, the geochemical anomalies of the content of the Cu, Pb, and Zn elements reflect the concentration of copper forming ore bodies in the mineralized zone, and clearly show the concentration in three distinct zones. The trend surface analysis which was employed to determine spatial variations and relationships among these good indicator elements and anomalous areas revealed relative changes in the content of the indicator elements, and they can be considered as regular. Moreover, the goodness of fit obtained trend functions of Pb and Zn, and Cu elements is a third-degree trend surface model. These results indicate that the models can be useful in studying geochemical anomalies and analyzing the tendency of the concentration of indicator elements in the Suoi Thau-Sang Than region. Additionally, it is suggested that the statistical analysis shows a remarkable potential to use the bottom river sediments in the region to investigate polymetallic mineralization. Moreover, geochemical data can help to evaluate geochemical anomalies of the pathfinder elements and potential mineral mapping of the Suoi Thau-Sang Than region in Northeast Vietnam

ĐÁNH GIÁ MỨC ĐỘ TIN CẬY CỦA TRỮ LƯỢNG THAN MỎ CAO SƠN, QUẢNG NINH BẰNG MÔ HÌNH TOÁN ĐỊA CHẤT

Abstract. The Cao Son mine is located in the southern part of the Quang Ninh province. It belongs to the Hon Gai coal zone, where many coal resources have been estimated in Vietnam. Based on synthesizing and processing data of the mining geological parameters by using stable random function and statistical methods, results show that the coal reserve reliability depends on some elements such as geological conditions, system and the grid exploration density, and methods of interpolated geological documents, and estimating of mineral resources methods. The stable random function for calculating the affected range indicates that most of the exploration works satisfy the appropriate pattern grid exploration for reserve level 122 in the Cao Sơn mine. The statistic models based on the confidence probability of 0.90 are applied in this paper to estimate coal reserve reliability in the study area, resulting in ± 15.36 ÷ ± 17.36% of coal reserve errors. It indicates that calculating coal resources during the exploration process is good enough for the exploited design. Results also provide an overview of the affected elements of coal resource reliability, serving as a basis for determining the errors of coal resources in the Cao Son mine. These can be applied to other deposits occurring in similar geological settings. Keywords: coal reserves, geomathermatic models, Cao Son mine, Quang Ninh provinceTóm tắt. Mỏ than Cao Sơn nằm về phía nam tỉnh Quảng Ninh, thuộc dải than Hòn Gai, nơi được đánh giá là một trong những khu vực có triển vọng lớn về than khoáng ở nước ta. Trên cơ sở tổng hợp tài liệu, xử lý số liệu về các thông số địa chất – công nghiệp mỏ bằng mô hình hàm ngẫu nhiên ổn định và toán thống kê cho thấy độ tin cậy về trữ lượng than mỏ Cao Sơn phụ thuộc vào các thông số như địa chất, hệ thống và mật độ mạng lưới thăm dò, phương pháp nội suy tài liệu địa chất và phương pháp xác định các thông số tính trữ lượng. Kết quả xác định theo mô hình hàm ngẫu nhiên cho thấy khoảng cách các công trình thăm dò đều nằm trong kích thước đới ảnh hưởng, điều đó nói lên rằng mạng lưới thăm dò đã áp dụng về cơ bản phù hợp với tính chất đẳng hướng tương đối của các vỉa than và đáp ứng yêu cầu thăm dò tỷ mỷ mỏ than Cao Sơn. Kết quả đánh giá sai số trữ lượng than bằng mô hình toán thống kê ở các diện tích chi tiết hoá thuộc mỏ Cao Sơn cho thấy với xác suất tin cậy 0,90 thì sai số trữ lượng thay đổi từ ± 15,36 ÷ ± 17,36%, nghĩa là trữ lượng than tính toán trong giai đoạn thăm dò tỷ mỉ bảo đảm độ tin cậy. Kết quả nghiên cứu góp phần lựa chọn các yếu tố ảnh hưởng đến độ chính xác và tin cậy trong đánh giá trữ lượng than mỏ Cao Sơn nói riêng và cho các khu mỏ khác có điều kiện tương tự nói chung. Từ khóa: trữ lượng than, mô hình toán địa chất, mỏ Cao Sơn, tỉnh Quảng Nin

The complex tectonic events and their influence on formation of mineral deposits in Northwest Vietnam PhD dissertation = Wydarzenia kształtujące tektonikę północno-zachodniego Wietnamu i ich wpływ na powstawanie surowców mineralnych : rozprawa doktorska /

Praca doktorska. Akademia Górniczo-Hutnicza im. Stanisława Staszica (Kraków), 2011.Zawiera bibliogr.Dostępna także w wersji drukowanej.Tryb dostępu: Internet.Modern geomorphology, hydrographic features, history of investigations, outline of geology, sedimentary rocks, magmatic units, geological structures, faults, nappes, plate tectonics, tectonic subdivision of Northwestern Vietnam, methodology, division of magmatic rocks, method of mineralization analysis, digital elevation model, remote sensing image, focal mechanism solution of earthquakes, magmatics, petrography, geochronology, geochemistry, modeling, geomorphic introduction, lineament models, criteria adopted for determining the tectonic lineaments, lineament extraction by drainage network analysis, lineament extraction by terrain analysis, lineament correlation between the drainage network, terrain analysis, domain analysis of aligned morphological features, geological field data, Red River fault zone, RRFZ, Dien Bien-Lai Chau fault zone, DBFZ, distribution of earthquake epicentres in the northern Vietnam, focal mechanism of earthquakes, characteristics of fault based on their focal mechanisms, Son La Fault, Da River fault, Dien Bien – Lai Chau Fault, Chieng Khuong Fault, mineral deposits, iron, chromium, copper, lead-zinc, gold, allite - siallite, molybdenum, pyrite, potassium-sodium, graphite, rare earth, radioactive ores, mineralization related to geological setting, geochemical anomaly related mineralization, hydrothermal alteration related to mineralization, geological evolution, tectonics, metallogenic type related to metamorphic rocks during Proterozoic, metallogeny in Early Palaeozoic – Devonian – Carboniferous, metallogenic type related to Upper Permian Ophiolite belt, in Late Permian-Triassic Indosinian, in Yanshanian, Jurassic-Cretaceous, in Himalayan, Palaeogene, tectonic processes conducive to the formation of the mineral deposits, geochronological data and chemical compositions of ore deposits, size, content of orebodies, their statistical distribution, list of ore deposits and occurrences in relation to host rocks of the NWVN, NEIC, Earthquake Search Results, http://www.neic.cr.usgs.gov, Global CMT Catalo

Tectonics and magmatism in Northwest Vietnam Tektonika i magmatyzm północno-wschodniego Wietnamu /

Tyt. z nagłówka.Bibliografia s. 350-351.Dostępny również w formie drukowanej.STRESZCZENIE: Na tle tektoniki płyt Azji południowo-wschodniej przedstawiono położenie północno-wschodniego Wietnamu i pięć grup skał magmowych genetycznie związanych z tą tektoniką. Najstarsza związana jest z powstawaniem Gondwany, druga obejmuje granitoidy związane z kolizjami i powstawaniem struktur kaledońsko-hercyńskich, trzecia zawiera ofiolity Paleotetydy, czwarta to anorogeniczne, jurajsko-kredowe granitoidy wewnątrzpłytowe, piąta, kenozoiczna, reprezentowana jest przez granitoidy - efekt uskoków po kolizji Indii z Azją. KEYWORDS: Vietnam, plate tectonics, magmatism, Paleozoic, Mesozoic, Cenozoic. SŁOWA KLUCZOWE: Wietnam, tektonika płyt, magmatyzm, paleozoik, mezozoik, kenozoik

Research identify the group for lead – zinc ore type to prepare exploration in Ban Lim area, Caobang province, Vietnam

Ban Lim area, Caobang province has proposed high potential of lead-zinc resources, which have occurred in different geological formations. In this paper, based on the collecting, synthetics and processing geological data, especially applied mathematical methods to recognize studied objects of exploration process and quantitative description. The results show that the lead-zinc orebodies in Ban Lim area are mainly occurred in lens-shaped and distributed in layered surfaces of dolomitized limestone of Coc Xo formation. The average lead-zinc content of the orebodies is in a range from 3.27% to 8.33%, its coefficient of variation (Vc) is in a range from 13.71% (evenly) to 137.92% (very unevenly). On the whole, the lead-zinc contents of the orebodies in Ban Lim area mainly comply with the standard normal distribution. The average thicknesses of the orebodies are in a range from 0.92 m to 6.48 m, its coefficient of variation (Vm) is in the range from 8.7% (stable) to 132.95% (very unstable). Quantitative calculation results have shown that Ban Lim lead-zinc deposit belongs to group III of deposits. For the exploration of this type of minerals, it is recommended to use linear grid pattern. Appropriate exploration grid pattern for category 122 reserve is (60-80)×(30-40) m

Identifying Correlation of Coal Seams in the Tien Hai Area, Northern Vietnam by Using Multivariate Statistic Methods

In northern Vietnam, the Tien Hai area is considered a high potential area of coal deposits. Two hundred fifty-six geochemical coal samples of 13 cores in the Tien Hai area investigate coal seams and coal deposits to identify the correlation of coal seams. According to the statistical method and cluster analysis of geochemical samples, the results indicate that the Mg, V, As, Ca, Zn, Cr, Co, K, Na, Sr, Fe, Ge, Re, U, Mo, Th, and Ga elements are good indicator elements of the major and trace elements in coal. Most of them comply with the normal or lognormal distribution rules. Besides, the Yb, Sc, Ho, Er, Tm, Lu, Y, Tb, Pr, Dy, and Sm elements are also good indicator elements for rare earth elements in the region. Therefore, the selected elements are used to identify the correlation of the coal seams in the Tien Hai area. Based on the similarity degree between studied objects, the results of grouping boreholes in coal seams show that the correlation of coal seam TV2-11 is suitable and acceptable, the coal seams TV3-6a, TV3- 6b, and TV3-6c can be grouped into the coal seam TV3-6. These results present that the models can help study geochemical coal samples and identify the correlation of the coal seams in the Tien Hai area. Additionally, the statistical analysis shows a remarkable degree to determine the correlation of the coal seams. Geochemical coal data can help to evaluate the indicator elements of the major, trace elements, and rare earth elements in coal seams and coal rashing of adjoining and pillar rocks in the Tien Hai area, northern Vietnam

Ocena zasobów konkrecji polimetalicznych w rejonie Suoi Thau-Sang Than, północno-wschodnim Wietnamie

1,720 chemical, mineral, and petrography samples in the Suoi Thau-Sang Than area, northeastern Vietnam were collected to investigate polymetallic nodules resource. The similarity-analogy in ore geology, direct calculation method for metallization parameters, and mineral resource estimation based on cutoff grade change methods are employed to estimate polymetallic nodules resource from the Suoi Thau, Sang Than, and Ban Kep areas in northeastern Vietnam. The similarity-analogy in ore geology indicates 1,785,000 tons Cu, 12,005,000 tons Pb+Zn, and 195 kg Au in total. The direct calculation method for metallization parameters shows 2,060,000 tons Cu, 13,648,000 tons Pb+Zn, and 224 kg Au in total. These methods display that the Sang Than area contains mainly polymetallic nodules in the studied area. Following the mineral resource estimation based on cutoff grade changes, estimation results indicate potential Pb-Zn nodules resource in the Ban Kep and Cu nodules resource in the Sang Than, while no potential Au nodules resource in the Suoi Thau and the Sang Than as well as the Ban Kep. The estimation results obtained from mineral resource estimation based on cutoff grade changes are suitable with the results from the traditional geometric block methods. Our study suggests that the Sang Than area can be considered as a potential Cu nodules resource, and the Ban Kep area is potential Pb-Zn nodules resource in northeastern Vietnam for future exploitation, while there is no potential polymetallic nodules resource in the Suoi Thau area. Furthermore, the one resource estimation based on cutoff grade changes method displays an overview of the prospect on polymetallic nodules resources, indicating that this method can serve as a basis for the proposed selection of the prospective areas for effective Cu, Pb-Zn, and Au mineral exploration in the Suoi Thau-Sang Than area, northeastern Vietnam.W celu zbadania zasobów konkrecji polimetalicznych zebrano 1,720 próbek substancji chemicznych, minerałów i petrografii z obszaru Suoi Thau-Sang Than w północno-wschodnim Wietnamie. Podobieństwo-analogia w geolo-gii rudy, metoda bezpośredniego obliczania parametrów metalizacji i szacowania zasobów mineralnych w opar-ciu o metody zmian zawartości granicznej są wykorzystywane do szacowania zasobów konkrecji polimetalicz-nych w obszarze Suoi Thau, Sang Than i Ban Kep w północno-wschodnim Wietnamie. Podobieństwo-analogia w geologii rudy wskazuje łącznie na 1,785,000 ton Miedzi, 12,005,000 ton Ołowiu + Cynków i 195 kg Żłota. Meto-da bezpośredniego obliczania parametrów metalizacji pokazuje łącznie 2 060 000 ton Miedzi, 13,648,000 ton Ołowiu + Cynków i 224 kg Żłota. Te metody pokazują, że obszar Sang Than zawiera głównie konkrecje polimeta-liczne na badanym obszarze. Po oszacowaniu zasobów mineralnych na podstawie zmian zawartości granicznej, wyniki oszacowań wskazują na potencjalny zasobów konkrecji Ołowiu - Cynków w Ban Kep i Miedzi w Sang Than, natomiast nie ma potencjalnego zasobu konkrecji Żłota w Suoi Thau i Sang Than, a także w Ban Kep. Wy-niki uzyskane z szacowania zasobów mineralnych na podstawie zmian zawartości granicznej są zgodne z wyni-kami tradycyjnymi metodami bloków geometrycznych. Nasze badanie sugeruje, że obszar Sang Than można uznać za potencjalny zasób konkrecji Miedzi, a obszar Ban Kep jest potencjalnym zasobem konkrecji Ołowiu + Cynków w północno-wschodnim Wietnamie do przyszłej eksploatacji, natomiast w obszarze Suoi Thau nie ma potencjalnego zasobu konkrecji polimetalicznych. Co więcej, oszacowanie zasobu w oparciu o metody zmian zawartości granicznej przedstawia przegląd perspektyw dotyczących zasobów konkrecji polimetalicznych, wska-zując, że metoda ta może służyć jako podstawa do proponowanego wyboru perspektywicznych obszarów efek-tywnych Miedzi, Ołowiu-Cynków i Żłota poszukiwanie minerałów w obszarze Suoi Thau-Sang Than w północno-wschodnim Wietnamie

Sulfur and lead isotope geochemical characteristics of Pb-Zn deposits in the Khau Loc zone, northeastern Vietnam, and their significance

In northeastern Vietnam, the Khau Loc zone is considered to have high potential for lead-zinc mineralization. The lead isotope data for 18 galena samples and 18 ones of δ34S isotope data (including galena and pyrite samples) were collected from lead-zinc ore deposits in some areas in the Khau Loc zone, including Phia Dam, Khuoi Man, Ban Lin, Lung Dam, and Ta Pan. These were employed to investigate the sulfur and lead isotope geochemical characteristics of Pb-Zn deposits and their significance in this study. The samples were analyzed using the LA-ICP-MS to show that the Pb isotopic ratios of 206Pb/204Pb, 207Pb/204Pb, and 208Pb/204Pb in the galena samples range from 17.8908 to 18.6012, 15.5794 to 16.1025, 38.4420 to 39.2118, with the average values of 18.296, 15.749, and 38.812, respectively. The pyrite and galena samples had the δ34S isotope, ranging from 9.0 to 15.106. The sulfur isotope systematics implies that most of the lead-zinc ore formations originated from marine sedimentary evaporation deposits and magmatic intrusion-volcanic eruption sources rich in silica. The distribution of lead isotopic ratios had a well-defined cluster for each deposit, indicating the formation of lead-zinc deposits and lower crust and orogen trends. In addition, these findings of lead isotopic ratios and δ 34S isotopes proved that the Khau Loc zone is an activated structure with continuous growth in continental crust thickness during the early Proterozoic and Cenozoic periods. Furthermore, the study results also presented the evolution of material sources involved in the formation of lead-zinc ores in the Khau Loc zone

Neoproterozoic granitoids of northwest Vietnam and their tectonic implications

A combined study of whole-rock geochemical and Sr-Nd isotopic data, and zircon U-Pb geochronological and Hf isotopes has been carried out for several Neoproterozoic intrusions, including the Lung Thang, Posen and Sin Quyen in the Phan Si Pan Zone, northwest Vietnam to constrain their age, petrogenesis and tectonic implications. The Lung Thang and Posen intrusions, mainly composed of granodiorite, were formed at 803–777 Ma and are characterized by moderate SiO2 (64.43–66.65 wt.%), and K2O (4.05–4.89 wt.%), with A/CNK and A/NK values of (0.94–1.03) and (1.72–2.11), respectively. They have negative whole-rock εNd(t) (−6.16 to −3.73) and zircon εHf(t) values (−7.9 to −4.1), which suggest that the Lung Thang and Posen intrusions were generated by partial melting of ancient, K-rich crustal rocks. The Sin Quyen intrusion, occurring as dykes, is composed of monzodiorite and was emplaced at 742 ± 3 Ma. The Sin Quyen intrusion has high alkalies (K2O+Na2O = 7.42–7.47 wt.%), and low MgO (Nd(t) and zircon εHf(t) values are −6.15 to −5.92 and −5.8 to + 8, respectively. These geochemical characteristics suggest that the Sin Quyen intrusion was produced by the partial melting of ancient crustal sources mingled with mantle-derived components. Geochemically, the Lung Thang, Posen and Sin Quyen intrusions are medium- to high-K, calc-alkaline in nature and show enrichment in LILE (Th, U, K, Rb) and LREE, and strong negative anomalies of Nb, Ta, and Ti. Such geochemical characteristics suggest that they formed in a subduction-related tectonic environment. The geochronological and geochemical correlation of these intrusions with those along the southwestern margin of the Yangtze Block in South China suggests that the Phan Si Pan zone in northwestern Vietnam is a constituent of the SW Yangtze Block. Additionally, these intrusions show a significant correlation with other contemporaneous magmatic rocks in the northeast Indochina Block, Lhasa Block, the northwestern margin of Greater India as well as those in Seychelles and northern Madagascar. This correlation suggests a similar history and synchronous episode of crustal growth/recycling in an Andean-type arc system along the western and northern margin of the Rodinia supercontinent during the Neoproterozoic.</p

Tumour microbiomes and Fusobacterium genomics in Vietnamese colorectal cancer patients.

Perturbations in the gut microbiome have been associated with colorectal cancer (CRC), with the colonic overabundance of Fusobacterium nucleatum shown as the most consistent marker. Despite its significance in the promotion of CRC, genomic studies of Fusobacterium is limited. We enrolled 43 Vietnamese CRC patients and 25 participants with non-cancerous colorectal polyps to study the colonic microbiomes and genomic diversity of Fusobacterium in this population, using a combination of 16S rRNA gene profiling, anaerobic microbiology, and whole genome analysis. Oral bacteria, including F. nucleatum and Leptotrichia, were significantly more abundant in the tumour microbiomes. We obtained 53 Fusobacterium genomes, representing 26 strains, from the saliva, tumour and non-tumour tissues of six CRC patients. Isolates from the gut belonged to diverse F. nucleatum subspecies (nucleatum, animalis, vincentii, polymorphum) and a potential new subspecies of Fusobacterium periodonticum. The Fusobacterium population within each individual was distinct and in some cases diverse, with minimal intra-clonal variation. Phylogenetic analyses showed that within four individuals, tumour-associated Fusobacterium were clonal to those isolated from non-tumour tissues. Genes encoding major virulence factors (Fap2 and RadD) showed evidence of horizontal gene transfer. Our work provides a framework to understand the genomic diversity of Fusobacterium within the CRC patients, which can be exploited for the development of CRC diagnostic and therapeutic options targeting this oncobacterium