Liao Y.-C.,Bureau of Mineral Resources
Geology in China | Year: 2012
In the past, the adding of aluminum and reducing of iron or the separation of aluminum from iron should be adopted as the first step in the application of high iron bauxite, as indicated by most previous literatures. This paper describes physical and chemical characteristics of the diaspore type high iron bauxite in the ore bed of Xianrenyan Rock in Zunyi. The samples of XCK5 and XCK4 of high iron bauxite were collected, the former is characterized by Al 2O3 53.61%,A/S 7.63,and Fe2O3 21.96%, whereas the latter is characterized by Al2O3 51.71%, A/S 7.16,and Fe2O3 24.89%. The Bayer dissolution test shows that the XCK5 has absolute dissolution rate 83.98% and relative dissolution rate 96.65%, chemical alkali consumption 57.9 kg(NaOH)/t(Al 2O3), whereqs the XCK4 shows absolute dissolution rate 80.02%, relative dissolution rate 93.01%, and chemical alkali consumption 34.9 kg (NaOH)/t (Al2O3). The test also reaches good result in red mud settlement. Therefore, the process chain of the application of high iron bauxite can be considerably shortened in that it is not necessary to add aluminum and reduce iron or separate aluminum from iron first before the application. The result obtained by the authors provides a new way for this kind of ore applications and researches.
Zhang H.-F.,CAS Institute of Geology and Geophysics |
Ying J.-F.,CAS Institute of Geology and Geophysics |
Tang Y.-J.,CAS Institute of Geology and Geophysics |
Li X.-H.,CAS Institute of Geology and Geophysics |
And 2 more authors.
Gondwana Research | Year: 2011
The Archean lithospheric root of the North China Craton (NCC) has been considerably eroded and modified by Phanerozoic magmatic processes. Here we investigate the decratonization of the NCC through U-Pb and Hf isotopic analyses of zircons from Cenozoic basalts in the Liaodong Peninsula using ion-probe and MC-ICPMS techniques. The U-Pb zircon geochronology identifies three zircon populations: Precambrian, Paleozoic and Mesozoic. The Precambrian zircons yield 207Pb/206Pb ages of 2275-2567Ma with a peak at around 2.5Ga. They define a U-Pb discordia with upper intercept ages of 2447±50Ma to 2556±50Ma and a wide range of Hf TDM ages with a mode at 2.7-2.8Ga. Our results clearly demonstrate the presence of an Archean lower crust in the Liaodong region. The Paleozoic zircons from the Liaodong region lack the clear internal zoning and are subhedral to rounded in shape, and yield a narrow 206Pb/238U concordant ages of 419-487Ma with a weighted mean age of 462±16Ma. The Mesozoic zircons predominantly show crystallization in the early Cretaceous and yield a relatively large range in 206Pb/238U ages from 100 to 138Ma (n=53) with a peak around 120Ma. Three samples give indistinguishable weighted mean 206Pb/238U ages of 120±5Ma, 120±4Ma and 121±2Ma. These early Cretaceous zircons have enriched Hf isotope compositions with εHf(t) values from -26 to -16. Our results provide important constraints on episodic magmatism during the Phanerozoic in the Liaodong region, which led to substantial reactivation of the Archean basement of the North China Craton. © 2010 International Association for Gondwana Research.
Li W.,China University of Geosciences |
Zeng P.,Bureau of Mineral Resources |
Hou Z.,Chinese Academy of Geological Sciences |
White N.C.,University of Tasmania
Economic Geology | Year: 2011
The Pulang porphyry copper deposit recently discovered in northwestern Yunnan province, is located at the south end of the Triassic Yidun island arc. To date, 15 mineralized porphyry deposits have been defined in the Pulang area and the copper resource is estimated to exceed 10 Mt. The Pulang deposit, as currently defined, is made up of five ore-bearing porphyry deposits, covering an area of approximately 9 km2. Intermediate acidic porphyritic intrusions composed of quartz-diorite, monzodiorite, quartz-monzonite, and granodiorite are widespread in the Pulang area. The alteration zones identified with the porphyry deposits include silicic, potassium silicate, quartz-sericite, and propylitic zones. The porphyry deposits have hornfels at the contact with slate, sandstone, and andesite. Re-Os ages of molybdenite, and Ar/Ar and K-Ar dating of biotite indicate that the Pulang porphyry copper deposit formed during the Indosinian tectonic episode, with the main ore formation taking place from 216 to 213 Ma (Late Triassic, Norian); however, the whole process of hydrothermal activity, including overprinting, may have extended from 235 to 182.5 Ma. © 2011 Society of Economic Geologists, Inc.
Jiang M.,Bureau of Mineral Resources |
Lin Y.,Finnish Geodetic Institute
IEEE Geoscience and Remote Sensing Letters | Year: 2013
This study proposed and tested a multistep method for the recognition of individual deciduous trees in leaf-off aerial ultrahigh spatial resolution remotely sensed (UHSRRS) imagery. This topic has received limited coverage in previous endeavors, which focused mainly on the detection and delineation of coniferous trees in remotely sensed images with relatively lower spatial resolutions. Thus, the traditional algorithms tend to fail in case of the referred scenario. In order to fill this technical gap, an algorithm that joins mathematical morphological operations and marker-controlled watershed segmentation was first assumed for the extraction of single trees in UHSRRS images. Next, a distribution-free support vector machine (SVM) classifier was applied to distinguish the extracted segments as deciduous or coniferous trees, merely in terms of two newly-derived morphological features. Experimental evaluations indicated that the integral solution plan can extract and classify the deciduous and coniferous trees in the leaf-off aerial UHSRRS images of local dense forest for test with correctness over 92% and 70%, respectively. Overall, the recognition results with >66% correctness have primarily validated the proposed technique. © 2004-2012 IEEE.
Coleman D.S.,University of North Carolina at Chapel Hill |
Mills R.D.,University of North Carolina at Chapel Hill |
Zimmerer M.J.,Bureau of Mineral Resources
Elements | Year: 2016
Beneath volcanoes are magmas that never erupt but that become frozen into feldspar- and quartz-rich rocks broadly called granite. Where the crystallized magmas form bodies with distinctive textures, they are grouped into named units-plutons. The rate (pace) at which magmas accumulate into plutons is fundamental to understanding both how room is made for the magmas and how unerupted and erupted magmas are connected. Dating plutonic rocks suggests that plutons accumulate slowly. Although the pace of magma accumulation does not preclude direct connections between plutons and small volcanic eruptions, it appears to be far too slow to support connections between most plutons and supereruptions.