Metallogenic implications of biotite chemical composition: Sample from Cu-Mo-Au mineralized granitoids of the Shah Jahan Batholith, NW Iran

Abstract Igneous biotite has been analyzed from three I-type calc-alkaline intrusives of the Shah Jahan Batholith in NW Iran, which host several Cu-Mo-Au prospects. The XMg (Mg/Mg+Fe) value of biotite is the most significant chemical factor and the relatively high value of XMg corresponds to relatively high oxidation states of magma (estimated fO2 is mostly 10−12.5 to 10−7.5 bars), which is in good agreement with their host intrusions' setting and related ore occurrences. Based on criteria of AlIV and AlVI values, all studied biotites are primary (AlVI = 0), and based on Altotal values (2.23–2.82 apfu) are in distinctive ranges of mineralized granitoid (Altotal=3.2 apfu). The maximum F content of biotite from the Shah Jahan intrusions is moderately higher than those from some other calc-alkaline intrusions related to Cu-Mo porphyries in the world, and in contrast, Cl content is relatively lower. It is likely a result of primary magmatic vs. secondary hydrothermal origin, as well as the Mg-rich characteristics of the biotite in Shah Jahan. XMg values do not correlate with F and Cl contents of biotite, suggesting that biotite records changes in the F/OH and Cl/OH ratios in coexisting melt/fluids. It is consistent with F-compatible and Cl-incompatible behavior during fractional crystallization of wet calc-alkaline I-type granitoid magma generated at subduction related arc settings. The fugacity ratios of (H2O/HF), (H2O/HCl) and (HF/HCl) magmatic solutions coexisting with biotite illustrate similar trends in the three intrusions, which can be due to parental magma sources and/or indicate occurrence of similar magmatic processes prior to or contemporaneous with exsolution of fluids from melt. The observed trends caused F-depletions and Cl-enrichments within developed magmatic-hydrothermal systems which are one of the essential characteristics of potential Cu-Mo-Au mineralized I-type granitoids

Initial oak regeneration responses to experimental warming along microclimatic and macroclimatic gradients

Quercus spp. are one of the most important tree genera in temperate deciduous forests in terms of biodiversity, economic and cultural perspectives. However, natural regeneration of oaks, depending on specific environmental conditions, is still not sufficiently understood. Oak regeneration dynamics are impacted by climate change, but these climate impacts will depend on local forest management and light and temperature conditions. Here, we studied germination, survival and seedling performance (i.e. aboveground biomass, height, root collar diameter and specific leaf area) of four oak species (Q. cerris, Q. ilex, Q. robur and Q. petraea). Acorns were sown across a wide latitudinal gradient, from Italy to Sweden, and across several microclimatic gradients located within and beyond the species' natural ranges. Microclimatic gradients were applied in terms of forest structure, distance to the forest edge and experimental warming. We found strong interactions between species and latitude, as well as between microclimate and latitude or species. The species thus reacted differently to local and regional changes in light and temperature ; in southern regions the temperate Q. robur and Q. petraea performed best in plots with a complex structure, whereas the Mediterranean Q. ilex and Q. cerris performed better in simply structured forests with a reduced microclimatic buffering capacity. The experimental warming treatment only enhanced height and aboveground biomass of Mediterranean species. Our results show that local microclimatic gradients play a key role in the initial stages of oak regeneration; however, one needs to consider the species-specific responses to forest structure and the macroclimatic context

Words apart: Standardizing forestry terms and definitions across European biodiversity studies

Forest biodiversity studies conducted across Europe use a multitude of forestry terms, often inconsistently. This hinders the comparability across studies and makes the assessment of the impacts of forest management on biodiversity highly context-dependent. Recent attempts to standardize forestry and stand description terminology mostly used a top-down approach that did not account for the perspectives and approaches of forest biodiversity experts. This work aims to establish common standards for silvicultural and vegetation definitions, creating a shared conceptual framework for a consistent study on the effects of forest management on biodiversity. We have identified both strengths and weaknesses of the silvicultural and vegetation information provided in forest biodiversity studies. While quantitative data on forest biomass and dominant tree species are frequently included, information on silvicultural activities and vegetation composition is often lacking, shallow, or based on broad and heterogeneous classifications. We discuss the existing classifications and their use in European forest biodiversity studies through a novel bottom-up and top-driven review process, and ultimately propose a common framework. This will enhance the comparability of forest biodiversity studies in Europe, and puts the basis for effective implementation and monitoring of sustainable forest management policies. The standards here proposed are potentially adaptable and applicable to other geographical areas and could be extended to other forest interventions. Forest management Multi-taxon Terminology Silviculture Data harmonizationpublishedVersio

Spartan Daily, March 15, 1963

Volume 50, Issue 88https://scholarworks.sjsu.edu/spartandaily/4435/thumbnail.jp

Soil legacies of tree species richness in a young plantation do not modulate tree seedling response to watering regime

•Trees have a strong and species-specific influence on biotic and abiotic properties of the soil. Even after the vegetation is removed, the effect can persist to form so-called soil legacies. We investigated the effects of soil legacies of tree species richness on the emergence and growth of tree seedlings, and how these legacy effects modulate the seedling responses to irrigation frequency. •We used a 9-year-old tree plantation on former agricultural land in Belgium, which is part of a biodiversity-ecosystem functioning experiment (FORBIO). Soil originating from monocultures and four-species plots, with different species combinations, was translocated to a greenhouse. Five tree species (Betula pendula, Fagus sylvatica, Pinus sylvestris, Quercus robur, and Tilia cordata) were sown and grown for one growing season in these soils. We performed a watering treatment (low and high irrigation frequency) to measure any potential interaction effects between the soil legacies and irrigation frequency. •There was no evidence for soil legacy effects of species richness on plant performance or their response to the irrigation frequency. However, the effect of irrigation frequency was dependent on species identity of the tree seedlings. Despite the lack of clear legacy effects, performance measures did show correlated responses that are likely due to species composition effects. •We ascribe these patterns to the young age of the forest and the agricultural past land use. At this early stage in forest development, the land-use history likely has a more important role in shaping soil characteristics that affect plant growth and their response to drought, than species diversity