Calgary, Alberta: August 31, 2016 – Mkango Resources Ltd. (TSXV: MKA; AIM: MKA) (the \’Company\’ or \’Mkango\’), is pleased to announce that it has released the Financial Statements and Management’s Discussion and Analysis for the period ending June 30,2016. The reports are now available on the Company’s website via the following link: http://www.mkango.ca/s/financials.asp, and will also be made
The Fe–Ti ore‐bearing Shangzhuang mafic intrusion in the Yanshan Orogenic Belt, north of the North China Craton, is characterized by compositional layering with troctolite, noritic gabbro and gabbro from the bottom to the top. The intrusive complex formed through fractionation of Fe‐, Ti‐ and Mg‐rich mafic hydrous magma. Here, we present a systematic petrological and mineral data on the various rock types from this intrusion. The plagioclase laths exhibit Na‐enriched rims with homogeneous cores and XAn content decreasing towards the margin, induced by sluggish coupled inter‐diffusion of (Ca + Al) versus (Na + Si). The reactions also resulted in amphibole and orthopyroxene rims surrounding olivine. Subsolidus equilibrium is indicated by Fe–Ti oxide lamellae in pyroxenes. The H2O content of the primary magma is estimated to be less than 2.5 wt.%, and initial crystallization temperature in the magma chamber is estimated as approximately 884 °C at a pressure of 3.45 kbar. The formation of the parent magma was due to the thermal–chemical erosion through mantle upwelling, basaltic underplating and heat input from convection of deep asthenosphere mantle, widely associated with the large‐scale Mesozoic lithospheric thinning beneath the North China Craton. Final emplacement of the Shangzhuang intrusion is related to the intra‐continental extensional setting, at a depth of approximately 14.5 km, suggesting large‐scale, post‐emplacement uplift and exhumation of the Yanshan Orogenic Belt in the Late Jurassic and Early Cretaceous. Copyright © 2016 John Wiley & Sons, Ltd.
The second member of the Middle Jurassic Shaximiao Formation in the rejuvenated Western Sichuan Foreland Basin contains tens of metres of thick incised valley successions. Incised valleys have been widely discussed in traditional models; however, quantitative and detailed analyses of geometric variations and their interpreted controls on ancient incised valleys have rarely been attempted in the past. Using an integrated dataset of seismic profiles, well logs and cores, this study quantifies the geometric parameters of incised valleys and investigates the smaller‐scale depositional patterns. (1) During this period, incised valleys (IV) were 5–17 km wide, 20–60 m deep and traceable for 120 km along their axis, placing these valleys among the longest seismically imaged incised valleys in the world. (2) Three nested incised valley successions IV‐1, IV‐2 and IV‐3 can be identified. Except for IV‐2, the incised valleys decrease in width and depth downstream. (3) In the downstream segment, the role of tectonism diminishes gradually, and periodic base‐level changes control the form and evolution of the incised valleys. A downstream decrease in the stream power appears to be responsible for the decreasing trend in the incised valley geometry. Copyright © 2016 John Wiley & Sons, Ltd.
Origin date/time: Sun, 28 Aug 16 22:58:50 GMT; Location: TREGARON,CEREDIGION 12KM ESE TREGARON ; Lat/long: 52.203,-3.761; Depth: 11km; Magnitude: 1.2
Origin date/time: Sun, 28 Aug 16 20:15:21 GMT; Location: DARWEN,LANCASHIRE ; Lat/long: 53.68,-2.498; Depth: 6km; Magnitude: 1
The Miaoya syenite and carbonatite complex is located in the southern margin of the South Qinling belt, central China. LA‐ICP‐MS zircon U–Pb dating reveals that the syenite and carbonatite have crystallization ages of 445.2 ± 2.6 Ma (MSWD = 0.66) and 434.3 ± 3.2 Ma (MSWD = 1.08), respectively. Both syenite and carbonatite display low ISr values (0.7004 to 0.7053) and depleted εNd(t) values of +1.1 to +5.5, with one‐stage Nd model ages of 0.65 to 0.94 Ga. Their zircon εHf(t) values are also similarly positive (+3.1 to +8.9), and one‐stage Hf model ages range from 0.71 to 0.92 Ga. Whole‐rock geochemistry suggests that the syenite belongs to the shoshonitic series and both syenite and carbonatite show identical REE and trace element patterns. The coeval intrusive ages, similar geochemical and Sr–Nd–Hf isotopic compositions suggest that the Miaoya carbonatite and associated syenite are genetically related to each other. We consider that the carbonatite could be a final product by protracted fractionation of a CO2‐rich alkaline melt. The depleted εNd(t) and zircon εHf(t) isotopes also indicate that the associated syenite and carbonatite could be originated from a mantle‐derived magma. The sources are likely composed of dominated HIMU mantle and minor EMI mantle. We propose that the Silurian Miaoya Complex was formed in the extensional rifting setting, associated with the mantle upwelling. Copyright © 2016 John Wiley & Sons, Ltd.
Origin date/time: Fri, 26 Aug 16 01:49:14 GMT; Location: STONE,STAFFORDSHIRE 4KM SW STONE ; Lat/long: 52.864,-2.18; Depth: 7km; Magnitude: 0.3
We undertook zircon U–Pb dating and geochemical analyses of the Weitingchagan (WT) pluton in the Dong Ujimqi area, Northeast China, with an aim of determining their ages, petrogenesis and sources, which are important for understanding the Late Palaeozoic tectonic evolution of the Xing‐Meng Orogenic Belt. The WT pluton consists of coarse‐ to medium‐grained porphyritic granites in the core and medium‐ to fine‐grained monzogranites in the rim, contains abundant microgranular enclaves and is intruded by small amounts of muscovite monzogranites. The results of LA‐ICP‐MS zircon U–Pb dating indicate that the WT composite pluton formed during the Late Carboniferous–Early Permian with the ages ranging from 289 Ma to 312 Ma. Petrological and geochemical characteristics of the WT pluton were derived from the partial melting of crustal materials, and the AFC process played an important role in the magmatic evolution. The porphyritic granites are I‐type granite, and the monzogranites and muscovite monzogranites are highly fractionated I‐type granite. Combined with previous studies on the contemporaneous magma‐tectonic activities in the Uliastai Continental Margin, the study suggests that the WT pluton formed in an extensional environment, which may relate to the closure of the Palaeo‐Asian Ocean. Copyright © 2016 John Wiley & Sons, Ltd.
In the Corsica Island, a stack of metamorphic continental units derived from the European continental margin is thrust over a pre‐Alpine basement during the convergence‐related processes in the Late Eocene–Early Miocene time span. The Piedigriggio‐Prato Unit is representative of these units. Its tectono‐metamorphic history has been reconstructed by an integrated approach, ranging from map‐ to meso‐ and microscopic scale analyses. This unit is characterized by a polyphase deformation history that consists of three deformation phases developed under retrograde metamorphism ranging from blueschist to sub‐greenschist facies metamorphic conditions. At the map‐scale, the Piedigriggio‐Prato Unit is characterized by km‐size isoclinal folds deformed by open to closed recumbent folds producing Type 3 fold interference pattern. The features of the deformations and the P–T conditions suggest that the first two phases were acquired during the ductile extrusion of the Piedigriggio‐Prato Unit. Before the Early Miocene, the gravitational collapse of over‐thickened continental crust produced vertical shortening and the consequently recumbent F3 folds. The exhumation history of the Piedigriggio‐Prato Unit can be viewed as representative for the exhumation of a continental crust fragment during the transition from the continental subduction to the continental collision. Copyright © 2016 John Wiley & Sons, Ltd.
Book Review Authors Jeffrey R. Thompson Corresponding author University of Southern California, Los Angeles, CA, USA Search for more papers by this author No abstract is available for this article. Ancillary Article Information DOI 10.1002/gj.2853 View/save citation Format Available Full text: HTML | PDF Copyright © 2016 John Wiley & …