Discrete Jurassic and Cretaceous Mineralization Events at the Xiangdong W(-Sn) Deposit, Nanling Range, South China

2020 ◽  
Vol 115 (2) ◽  
pp. 385-413 ◽  
Author(s):  
Yi-Qu Xiong ◽  
Yong-Jun Shao ◽  
Yanbo Cheng ◽  
Shao-Yong Jiang
Keyword(s):  
Early Cretaceous ◽  
South China ◽  
Late Jurassic ◽  
Stage I ◽  
Stage Ii ◽  
Quartz Veins ◽  
Nanling Range ◽  
Metallogenic Belt ◽  
Two Stages ◽  
Highly Evolved

Abstract The Xiangdong W(-Sn) deposit is hosted in the Dengfuxian multiphase granites (biotite, two-mica, and muscovite granites) within the Nanling Range metallogenic belt in south China. Previous studies suggested that the W(-Sn) mineralization in the Xiangdong deposit is related to the Late Jurassic two-mica granite, whereas recently W-Sn–bearing quartz veins have also been identified in muscovite granite. We present new cassiterite and zircon U-Pb ages to constrain the timing of W-Sn mineralization and related granitic magmatism. Our laser ablation-inductively coupled plasma-mass spectrometry U-Pb dating of zircon grains, combined with previous zircon ages, in addition to the trace element composition of the muscovite granite, suggest the muscovite granite in the Dengfuxian pluton was emplaced at 145 to 142 Ma and shows highly evolved features. Cassiterite grains from the ore-bearing veins in two-mica granite yielded U-Pb ages of 151.6 ± 3.7 and 141 to 138 Ma, whereas cassiterite grains from quartz veins occurring in muscovite granite yielded a U-Pb age of 136.8 ± 3.3 Ma. The new ages and detailed geologic evidence indicate that the Early Cretaceous muscovite granite is also genetically related to W-Sn mineralization. Combining this with previously published data from the Late Jurassic two-mica granites and related mineralization, we suggest that there were two stages of W-Sn mineralization at Xiangdong. Arsenopyrite geothermometry from the two stages suggests temperatures of 300° to 491° and 308° to 450°C in stage I and stage II, respectively. Wolframite grains from the two stages also show different characteristics and patterns for their major and trace elements. The enrichment in Sc in wolframite suggests low-pH and low-Eh conditions for a fluid containing F– and/or PO43− complexes during stage I, whereas higher contents of Nb and Ta and lower contents of Sc in wolframite from stage II indicate relatively lower pH and higher Eh conditions. In combination with data from other recent studies, we propose that the 145 to 130 Ma interval represents a newly recognized W-Sn metallogenic period linked with highly evolved granites in the Nanling Range metallogenic belt. The Early Cretaceous muscovite granite is an important new target for W and Sn resources in south China.

scholarly journals Zircon U-Pb and Pyrite Re-Os Isotope Geochemistry of ‘Skarn-Type’ Fe-Cu Mineralization at the Shuikoushan Polymetallic Deposit, South China: Implications for an Early Cretaceous Mineralization Event in the Nanling Range

Minerals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 480
Author(s):  
Shengbin Li ◽  
Yonghua Cao ◽  
Zeyou Song ◽  
Dan Xiao
Keyword(s):  
Contact Zone ◽  
Early Cretaceous ◽  
South China ◽  
Isotope Geochemistry ◽  
Time Interval ◽  
Mean Square ◽  
Geochronological Data ◽  
Nanling Range ◽  
Calcite Veins ◽  
Os Isotope

The Shuikoushan deposit is an economic ‘skarn-type’ polymetallic Pb-Zn deposit in South China. The deposit is located at the southern margin of the Hengyang basin in the northern part of the Nanling Range. Recently, economic Fe-Cu mineralization that occurs spatially connected to skarns along the contact zone between the granodiorite and limestones was discovered in the lower part of this deposit. Detailed zircon U-Pb geochronological data indicate that the granodiorite was emplaced at 153.7 ± 0.58 Ma (Mean Square of Weighted Deviates (MSWD) = 2.4). However, the pyrite Re-Os isochron age reveals that Fe-Cu mineralization formed at 140 ± 11 Ma (MSWD) = 8.1), which post-dates the emplacement of the granodiorite, as well as the previously determined timing of Pb-Zn mineralization (157.8 ± 1.4 Ma) in this deposit. Considering that Fe-Cu mineralization was connected with the contact zone and also faults, and that sulfide minerals commonly occur together with quartz and calcite veins that crosscut skarns, we interpret this mineralization type as being related to injection of post-magmatic hydrothermal fluids. The timing of Fe-Cu mineralization (140 ± 11 Ma) is inconsistent with a long-held viewpoint that the time interval of 145 to 130 Ma (e.g., Early Cretaceous) in the Nanling Range is a period of magmatic quiescence with insignificant mineralization, the age of 140 Ma may represent a new mineralization event in the Nanling Range.

scholarly journals HERMIONE, EVOLUTION OF ATe-BEARING EPITHERMAL MINERALIZATION, ARGOLIS, HELLAS

2007 ◽  
Vol 40 (2) ◽  
pp. 996 ◽  
Author(s):  
S. Tombros ◽  
K. St. Seymour
Keyword(s):  
Sedimentary Rocks ◽  
Ore Deposits ◽  
Stage I ◽  
Stage Ii ◽  
Quartz Veins ◽  
Minor Contribution ◽  
Epithermal Mineralization ◽  
Ore Bodies ◽  
Calcite Veins ◽  
Sandstone Formation

The Cu-Te-bearing pyrite deposits of Hermione, Argolis are hosted in Miocenic ophiolites. The ophiolites are overlain by a shale-sandstone formation with intercalations of limestones and manganiferous sedimentary rocks. The ore deposits form irregular lenticular or stratiform ore bodies, and veins. These ore bodies are related to volcanic activity in an arc-related rift at the margins of a palaeocontinent. Late N- to NNE-trending, sinistral, milky quartz-pyrite-calcite veins cut the host ophiolites. Alteration haloes of quartz-calcite, albite-sericitechlorite, and chalcedony-epidote-clay minerals are developed in the lavas as concentric shells, or as envelops that parallel the quartz veins. The telluriumbearing mineralization is developed in two successive stages, characterized by the assemblages: pyrite-(pyrrhotite)-magnetite-chalcopyrite-sphalerite (Stage I) and galena-sphalerite-freibergite-marcasite-chalcocite (Stage II), followed by a supergene stage. The cobaltiferous pyrite-chalcopyrite geothermometer defined two ranges of last-equilibration temperatures: 220° to 250°Cfor Stage I, and 120° to 195°Cfor Stage II. The calculated δ18 Ο and SD compositions of the mineralizing fluids, at 200° and 250°C, reflect the dominance of a magmatic component. The calculated δ SH2S fluid values reveal a magmatic source for the sulphur, with minor contribution from submarine sediments, whereas tellurium is proposed to be derived from a mafic-ultramafic source.

scholarly journals Two-Stage Late Jurassic to Early Cretaceous Hydrothermal Activity in the Sakar Unit of Southeastern Bulgaria

Minerals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 266
Author(s):  
Krzysztof Szopa ◽  
Anna Sałacińska ◽  
Ashley P. Gumsley ◽  
David Chew ◽  
Petko Petrov ◽  
...  
Keyword(s):  
Early Cretaceous ◽  
Late Jurassic ◽  
Hydrothermal Activity ◽  
Two Stage ◽  
Accessory Minerals ◽  
Icp Ms ◽  
Two Stages ◽  
Age Constraints ◽  
Hydrothermal Veins

Southeastern Bulgaria is composed of a variety of rocks from pre-Variscan (ca. 0.3 Ga) to pre-Alpine sensu lato (ca. 0.15 Ga) time. The Sakar Unit in this region comprises a series of granitoids and gneisses formed or metamorphosed during these events. It is cut by a series of post-Variscan hydrothermal veins, yet lacks pervasive Alpine deformation. It thus represents a key unit for detecting potential tectonism associated with the enigmatic Cimmerian Orogenic episode, but limited geochronology has been undertaken on this unit. Here we report age constraints on hydrothermal activity in the Sakar Pluton. The investigated veins contain mainly albite–actinolite–chlorite–apatite–titanite–quartz–tourmaline–epidote and accessory minerals. The most common accessory minerals are rutile and molybdenite. Apatite and titanite from the same vein were dated by U–Pb LA–ICP-MS geochronology. These dates are interpreted as crystallization ages and are 149 ± 7 Ma on apatite and 114 ± 1 Ma on titanite, respectively. These crystallization ages are the first to document two stages of hydrothermal activity during the late Jurassic to early Cretaceous, using U–Pb geochronology, and its association with the Cimmerian orogenesis. The Cimmerian tectono-thermal episode is well-documented further to the east in the Eastern Strandja Massif granitoids. However, these are the first documented ages from the western parts of the Strandja Massif, in the Sakar Unit. These ages also temporally overlap with previously published Ar–Ar and K–Ar cooling ages, and firmly establish that the Cimmerian orogeny in the studied area included both tectonic and hydrothermal activity. Such hydrothermal activity likely accounted for the intense albitization found in the Sakar Unit.

Superimposed deformation of the Solonker Belt and nearby regions in western Inner Mongolia, China

2018 ◽  
Vol 156 (5) ◽  
pp. 811-832 ◽  
Author(s):  
GUANZHONG SHI ◽  
CHAO LIANG ◽  
HUA WANG ◽  
CHUANYAN HUANG
Keyword(s):  
Structural Analysis ◽  
Tectonic Evolution ◽  
Inner Mongolia ◽  
Late Jurassic ◽  
Middle Triassic ◽  
Orogenic Belt ◽  
Far Field ◽  
Quartz Veins ◽  
Central Asian ◽  
Two Stages

AbstractThe deformation of the Solonker Belt and nearby regions is helpful for understanding the tectonic evolution of the Central Asian Orogenic Belt. This study carried out structural analysis in the Mandula and Ganqi areas of western Inner Mongolia, including the Solonker Belt, the Southern Orogenic Belt and the northern Yinshan Belt (Langshan range). Our results reveal that the Solonker Belt, the Southern Orogenic Belt and the northern Yinshan Belt underwent two stages (D1 and D2) of deformation during the Mesozoic period. The D1 stage produced the NNE-directed thrusts and asymmetric folds, indicating a NNE–SSW contraction. The northern Yinshan Belt, the Southern Orogenic Belt and the Solonker Belt formed as a series of NNE-verging tectonic nappes. The D2 stage developed the NE-trending folds and the SE- or NW-directed thrusts that cross-cut the D1 structures. The two events of nearly orthogonal or oblique shortening gave rise to the superimposed structures (e.g. fold interference patterns). The quartz veins that filled the fractures of the D1 deformation contain zircons of Middle Triassic U–Pb ages. The new dating data, along with the regional sedimentary hiatus, led us to infer that the D1 stage of deformation occurred in Middle Triassic time and the D2 stage occurred in Late Jurassic time. We consider that the D1 stage of deformation resulted from a convergent event, which might be related to the closure of the Palaeo-Asian Ocean or limited, narrow ocean basins; and the D2 stage of deformation was the far-field result of subduction of the Palaeo-Pacific Ocean and the closure of the Mongol-Okhotsk Ocean.

scholarly journals Workshop Guru SDN Melayu 7 Banjarmasin dalam Menyusun Soal Cerita Berbasis Kearifan Lokal untuk Meningkatkan Kemampuan Berpikir Kreatif

2019 ◽  
Vol 5 (1) ◽  
pp. 46-52
Author(s):  
Aminah Ekawati ◽  
Winda Agustina ◽  
Hajjah Rafiah
Keyword(s):  
Group Work ◽  
Creative Thinking ◽  
Thinking Skills ◽  
Stage I ◽  
Stage Ii ◽  
Story Problems ◽  
Active Participant ◽  
Know How ◽  
Level Of Understanding ◽  
Two Stages

SDN Melayu 7 is located in Banjarmasin Tengah and has implemented the 2013 curriculum. There are some problems found from interviews with the principal and some teachers, namely students, are more faced with routine questions and are required to be able to solve problems in the story of the question. While the teacher has difficulty making story questions that are easily understood by students. This activity aims to prepare teachers to know how to arrange story problems based on local wisdom in South Kalimantan to improve creative thinking skills. The approach used is active participant learning. The activity is divided into two stages, and stage I is focused on the question of story problems based on local wisdom in South Kalimantan, while in stage II, it is focused on the question of story problems based on local wisdom that can improve the ability to think creatively. To measure the success of each stage, an understanding questionnaire was given, and the work of the participant groups were seen. The activity is said to be successful if the average questionnaire comprehension is at least 75%. The results of the activity showed the level of understanding of the participants reached 93.61% in stage I and 91.94% in stage II. Also seen from the results of group work it can be concluded that participants can understand well the explanations given by the speakers.

Petrogenesis of Late Jurassic Pb–Zn mineralized high δ18O granodiorites in the western Nanling Range, South China

2020 ◽  
Vol 192 ◽  
pp. 104236
Author(s):  
Xiao Liu ◽  
Qiang Wang ◽  
Lin Ma ◽  
Derek A. Wyman ◽  
Zhen-Hua Zhao ◽  
...  
Keyword(s):  
South China ◽  
Late Jurassic ◽  
Nanling Range

scholarly journals On the Larval Development of Elminius Modestus Darwin

1949 ◽  
Vol 28 (2) ◽  
pp. 413-428 ◽  
Author(s):  
E. W. Knight-Jones ◽  
G. Duncan Waugh
Keyword(s):  
Larval Development ◽  
Size Distribution ◽  
Stage Iv ◽  
Stage I ◽  
Stage Ii ◽  
Naupliar Stage ◽  
Process Stage ◽  
Abdominal Appendages ◽  
Size Limits ◽  
Two Stages

Nauplii of the first two stages were obtained from adult Elminius modestus and larvae of all stages, except the smallest, were obtained from the plankton over Essex oyster beds.Over 200 nauplii of all sizes were measured. Their size distribution, plotted graphically, showed six peaks corresponding to six naupliar stages. The later stages were much more variable in size than the earlier stages.The size limits and characteristics of each naupliar stage are given. Briefly, Stage I has the fronto-lateral horns pointing backwards. Stage II has the caudal spine much longer than the abdominal process. Stage III has the abdominal process about as long as the caudal spine, but has no carapace fold posteriorly. Stage IV has a carapace fold but no sign of the abdominal appendages. Stage V has the rudiments of these appendages showing indistinctly within the abdomen. In Stage VI the abdominal appendages are prominent.

scholarly journals Multiscale Interactive Processes Underlying the Heavy Rainstorm Associated with a Landfalling Atmospheric River

Atmosphere ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 29
Author(s):  
Zhuang Zhang ◽  
X. San Liang
Keyword(s):  
Multiscale Analysis ◽  
Heavy Precipitation ◽  
Stage I ◽  
Stage Ii ◽  
Background Flow ◽  
Atmospheric River ◽  
Analysis Methodology ◽  
Two Stages ◽  
Multiscale Window Transform ◽  
Canonical Transfer

The heavy precipitation in Northern California—brought about by a landfalling atmospheric river (AR) on 25–27 February 2019—is investigated for an understanding of the underlying dynamical processes. By the peaks in hourly accumulation, this rainstorm can be divided into two stages (Stage I and Stage II). Using a recently developed multiscale analysis methodology, i.e., multiscale window transform (MWT), and the MWT-based theory of canonical transfer, the original fields are reconstructed onto three scale windows, namely, the background flow, synoptic-scale and mesoscale windows, and the interactions among them are henceforth investigated. In both stages, the development of the precipitation is attributed to a vigorous buoyancy conversion and latent heating, and besides, the instability of the background flow. In Stage I, the instability is baroclinic, while in Stage II, it is barotropic. Interestingly, in Stage I, the mesoscale kinetic energy is transferred to the background flow where it is stored, and is released back in Stage II to the mesoscale window again, triggering intense precipitation.

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