The Late Paleozoic magmatic evolution of the Aqishan-Yamansu belt, Eastern Tianshan: Constraints from geochronology, geochemistry and Sr-Nd-Pb-Hf isotopes of igneous rocks

The Aqishan-Yamansu belt in the Eastern Tianshan (Xinjiang, NW China) is an important mineralization belt. The belt mainly comprises Carboniferous volcanic, volcaniclastic and elastic rocks, and hosts many intermediate-felsic intrusions and Fe (-Cu) deposits. The biotite diorite, felsic brecciated tuff, granodiorite and syenite from the western Aqishan-Yamansu belt are newly zircon U-Pb dated to be 316.7 +/- 1.4 Ma, 315.6 +/- 2.6 Ma, 305.8 +/- 1.9 Ma and 252.5 +/- 1.4 Ma, respectively. The mafic rocks (mafic brecciated tuff and diabase porphyry) are tholeiitic to talc-alkaline series, LILE-rich (e.g., Rb, Ba and Pb), HFSE-depleted (e.g., Nb and Ta), and have high Mg-#(44-60), Nb/Ta (15.0-20.0), Ba/La (> 30) and Ba/Nb (> 57) values/ratios, and low Th/Yb ratios (< 1), probably originating from mantle wedge metasomatized by slab-derived fluids. The intermediate-felsic igneous rocks are LILE-rich, HFSE-depleted, with high Sr and Y contents showing typical of normal arc magma affinity. Moreover, the depleted epsilon(Hf)(t) (> 2.10) and positive epsilon(Nd)(t) (> 5.7), combined with variable Nb/Ta ratios (9.52-21.4), Y/Nb ratios (1.47-39.7) and Pb isotopes (Pb-206/Pb-204 = 16.225-17.640, Pb-207/Pb-204 = 15.454-15.520, Pb-208/Pb-204 = 37.097-38.025) suggest that these rocks were magma mixing products between juvenile crustal-derived magmas and minor mantle-derived magmas. Combined published works with our new ages, geochemical and isotopic data, we propose that the Aqishan-Yamansu belt was an Early Carboniferous fore-arc basin during the southward subduction of the Kangguer oceanic slab beneath the Yili-Central Tianshan block. With the continuing southward subduction, the Aqishan-Yamansu fore-arc basin initiated to close, which generated the mafic and intensive intermediate-felsic magmatism associated with regional Fe (-Cu) mineralization

Determination of complementary irrigation times for rainfed cultivation based on biomass optimization and soil erosion index in Yellow River Valley

Drought is the most important factor limiting the growth and production of wheat in China. Arid and semi-arid regions and high water consumption in the agricultural sector have led to various deficit irrigation strategies. The effect of the hydrological process on yield production has been evaluated in rainfed cultivation of wheat for the three climatic stations of Gansu Province, Yellow River Valley, China. A general framework was provided for rainfed cultivation of wheat in arid and semi-arid regions. Moreover, the best time and amount of complementary irrigation and its effect on increasing yield production have been evaluated using grey wolf optimization algorithm. The results showed that rainfed cultivation of wheat in a humid regime could be suggested without complementary irrigation. Conducting two complementary irrigations in semi-humid regime can increase the final yield of wheat by more than 150 kg/ha. The maximum yields in sustainable management were obtained 4,844, 4,510, and 4,408 kg/ha for Longnan, Tianshui, and Dingxi, respectively. HIGHLIGHTS This paper focuses on the modeling of the soil, water, and crop system with more details to improve the applicability.; The proposed method is an optimal policy by applying rainfed management and complementary irrigation.

Magnetite geochemistry of the Heijianshan Fe-Cu (-Au) deposit in Eastern Tianshan: Metallogenic implications for submarine volcanic-hosted Fe-Cu deposits in NW China

The Heijianshan Fe-Cu (-Au) deposit is located in the Aqishan-Yamansu belt in Eastern Tianshan, NW China. As a typical Fe-Cu deposit in the region, Heijianshan is hosted in the Upper Carboniferous Matoutan Formation submarine volcanic/volcaniclastic rocks. Alteration styles, mineral assemblages and vein crosscutting relationships divide the hydrothermal alteration and mineralization processes into seven stages, namely the chromite (Stage I), epidote (Stage II), magnetite (Stage III), pyrite (Stage IV), Cu (-Au) (Stage V), late veins (Stage VI) and supergene (Stage VII) alteration/mineralization stages. Magnetite mineralization comprises the hematite (Stage III-A) and main magnetite (Stage Ill-B) mineralization sub-stages. The Heijianshan magnetite ores consist of massive (with mushketovite (MOM) or sulfides (MOS)), disseminated (DO) and magnetite clasts (with chromite (MWC) or without chromite (MNC)) ores. Magnetite in massive- and disseminated ores is featured by (1) depletion in Zr, Nb and Ta; (2) low Ti (<2 wt.%) and Al (<1 wt.%); and (3) Ni/Cr >= 1, which all reflect a hydrothermal origin. Moreover, magnetite in massive-and disseminated ores has lower Cr (MOM: 0-13.2 ppm; MOS: 0-12.9 ppm; DO: 3.57-133 ppm) than magnetite clasts ores (MNC: 849-2544 ppm; MWC: 835-44,132 ppm). However, the high Cr in the magnetite clasts ores may have been inherited from the chromite they replaced. From the magnetite clasts to disseminated/massive ores, formation temperature decreased and fO(2) increased, which may represent the major controls on the formation of the various magnetite ore types. Compositions of the ore fluids and host rocks, formation of coexisting minerals and other physicochemical parameters (such as T and fO(2)) may have variably influenced the magnetite geochemistry in the different Heijianshan ore types, with fluid compositions probably playing the most important role. Discrimination diagrams, for instance, Cr vs. Co/Ni, Cr vs. Ti, V vs. Cr and Ni vs. Cr, may be useful for magnetite mineralization type differentiation in other submarine volcanic-hosted Fe/Fe-Cu deposits in the Aqishan-Yamansu belt. Geochemical discrimination diagrams, alteration and mineralization paragenesis indicate that the Heijianshan Fe-Cu (-Au) deposit is best classified as an IOCG-like deposit, which offers a new insight for classifying and characterizing ore genetic types for similar Fe and Fe-Cu deposits in Eastern Tianshan. (C) 2016 Elsevier B.V. All rights reserved

Geochemical evidence of the indirect pathway of terrestrial particulate material transport to the Okinawa Trough

The major source of particulate matter in the East China Sea (ECS) is the Changjiang (Yangtze) River. Sediment types, the geochemical indices of terrigenous and biogenic inputs (TOC, CaCO3 and Sc), and biomarker indices such as the carbon preference index (CPI) of long-chain n-alkanes and the cinnamyli vanillyl ratio (C/V) in surface sediments, all reveal that the influence of terrestrial material initially declines away from the mouth of the Changjiang River across the ECS continental shelf. However, the influence then strengthens from the middle ECS shelf toward the continental slope and the Okinawa Trough, because when the northeast winds prevail from September to April, the Changjiang River plume flows southwestward along the coast of China. Part of this flow turns eastward in the northern Taiwan Strait, and then joins the northeastwardly flowing Kuroshio to reach the Okinawa Trough. As the central ECS is bypassed, the sediments accumulated there are geologically older, carbonate-rich and organic poor than those found off the coast of China and in the Okinawa Trough

Differentially expressed genes involved in starch metabolism (A) and photosynthesis (B).

<p>Colored squares indicate up- or down-regulated genes with log₂ fold change (FC) ≥ 1.00 or ≤ -1.00.</p

Comparative PageMan display of perturbed pathways in <i>C</i>Las-affected <i>C</i>. <i>hystrix</i> and <i>C</i>. <i>sinensis</i>.

<p>The log₂ fold change of gene expression (mock-inoculated controls versus CLas-inoculated plants) was input into PageMan and subjected to a Wilcoxon test. Results were shown as a false-color heat-map-like display. Significantly up-regulated pathways are colored in red, while those colored in green are significantly down-regulated. Pathways without significant changes are white. Names of pathways are indicated on the right panel. CH, CH-M-VS-CH-HLB; CS, CS-M-VS-CS-HLB.</p

Gene ontology classification of differentially expressed genes in different citrus hosts in response to ‘<i>Candidatus</i> Liberibacter asiaticus’.

<p>BP, Biological Process; CC, Cell Component; MF, Molecular Function.</p

Statistic of differentially expressd genes (DEGs) of different citrus cultivars in response to <i>C</i>Las.

<p>CH, <i>Citrus hystrix</i>; CS, <i>C</i>. <i>sinensis</i>; M, Mock/healthy; HLB, Huanglongbing; CH-M-VS-CH-HLB, DEGs in HLB-infected <i>C</i>. <i>hystrix</i> compared with healthy control; CS-M-VS-CS-HLB, DEGs in HLB-infected <i>C</i>. <i>sinensis</i> compared with healthy control; CS-M-VS-CH-M, DEGs between healthy <i>C</i>. <i>hystrix</i> and healthy <i>C</i>. <i>sinensis</i>; CS-HLB-VS-CH-HLB, DEGs between HLB-infected <i>C</i>. <i>hystrix</i> and HLB-infected <i>C</i>. <i>sinensis</i>.</p

MapMan analysis of differentially expressed genes in <i>C</i>Las-affected <i>Citrus hystrix</i> (A) and <i>C</i>Las-affected <i>C</i>. <i>sinensis</i> (B) involved in stress responses.

<p>Red squares represent genes those were significantly up-regulated; green squares represent genes those were significantly down-regulated.</p