scholarly journals Lake Neor reveals how mountain vegetation responded to 7000 years of hydroclimate variability in northwestern Iran

2021 ◽  
Author(s):  
Khadijeh Alinezhad ◽  
Elias Ramezani ◽  
Morteza Djamali ◽  
Arash Sharifi ◽  
Alireza Naqinezhad ◽  
...  
Keyword(s):  
Hydroclimate Variability ◽  
Northwestern Iran ◽  
Mountain Vegetation

Alpine vegetation of the Ivanovskiy, Prokhodnoy and Rossypnoy Ridges (Western Altai)

2015 ◽  
pp. 96-124
Author(s):  
E. G. Zibzeev ◽  
T. A. Nedovesova
Keyword(s):  
Plant Communities ◽  
Wide Spectrum ◽  
Climate Forcing ◽  
High Mountain ◽  
Air Mass ◽  
Rich Diversity ◽  
Mountain Systems ◽  
Mountain Vegetation ◽  
Coenotic Diversity

The mountain systems are characterized by diverse ecological conditions (climate, geomorphological, soil, etc.). The wide spectrum of environmental conditions entails a rich diversity of plant communities growing on the small territory and determines the different flora and vegetation geneses. The uniqueness of floristic and coenotic diversities of the high-mountain vegetation of the south of Western Altai (Ivanovskiy, Prokhodnoi, and Rossypnoi Ranges) are associated with the effect of two climate-forcing factors such as the westerly humid air mass and dry warm airflow from the inner Kazakhstan regions. The paper summarizes the data on coenotic diversity (Zibzeev, 2010, 2012) and gives a syntaxonomic analysis of the high-mountain vege­tation in the Ivanovskii, Prokhodnoi, and Rossypnoi Ranges (Western Altai, Kazakhstan). The classification of plant communities was carried out using the Braun-Blanquet approach (Westhoff, van der Maarel, 1973). The relevés records were stored in the TURBOVEG database and classified by ­TWINSPAN (Hill 1979).

EXTREME HYDROCLIMATE VARIABILITY IN KENYA'S BARINGO BASIN DURING THE LATE PLIOCENE: THE DIATOM RECORD

2018 ◽  
Author(s):  
Karlyn Westover ◽  
◽  
Jeffery Stone ◽  
Nathan Rabideaux ◽  
Chad L. Yost ◽  
...  
Keyword(s):  
Late Pliocene ◽  
Hydroclimate Variability

HIGH-RESOLUTION STALAGMITE RECORD EXAMINING LOCAL HYDROCLIMATE VARIABILITY FROM A SHALLOW CAVE IN SEMI-ARID NEW MEXICO

2019 ◽  
Author(s):  
Natasha Sekhon ◽  
◽  
Jay L. Banner ◽  
Bryan Black ◽  
Nathan Miller ◽  
...  
Keyword(s):  
New Mexico ◽  
High Resolution ◽  
Hydroclimate Variability ◽  
Semi Arid

A comparison of asthma prevalence in adolescents living in urban and semi-urban areas in northwestern Iran

2021 ◽  
pp. 1-18
Author(s):  
Zahra Sabeti ◽  
Khalil Ansarin ◽  
Ensiyeh Seyedrezazadeh ◽  
Mohammad Asghari Jafarabadi ◽  
Venus Zafari ◽  
...  
Keyword(s):  
Urban Areas ◽  
Asthma Prevalence ◽  
Northwestern Iran

A lake sediment–based paleoecological reconstruction of late Holocene fire history and vegetation change in Great Basin National Park, Nevada, USA

2021 ◽  
pp. 1-15
Author(s):  
Christopher S. Cooper ◽  
David F. Porinchu ◽  
Scott A. Reinemann ◽  
Bryan G. Mark ◽  
James Q. DeGrand
Keyword(s):  
Great Basin ◽  
Relative Abundance ◽  
Vegetation Change ◽  
Fire History ◽  
Ice Age ◽  
Sediment Geochemistry ◽  
Catchment Scale ◽  
Composition And Structure ◽  
Hydroclimate Variability ◽  
Late Fifteenth

Abstract Analyses of macroscopic charcoal, sediment geochemistry (%C, %N, C/N, δ13C, δ15N), and fossil pollen were conducted on a sediment core recovered from Stella Lake, Nevada, establishing a 2000 year record of fire history and vegetation change for the Great Basin. Charcoal accumulation rates (CHAR) indicate that fire activity, which was minimal from the beginning of the first millennium to AD 750, increased slightly at the onset of the Medieval Climate Anomaly (MCA). Observed changes in catchment vegetation were driven by hydroclimate variability during the early MCA. Two notable increases in CHAR, which occurred during the Little Ice Age (LIA), were identified as major fire events within the catchment. Increased C/N, enriched δ15N, and depleted δ13C values correspond with these events, providing additional evidence for the occurrence of catchment-scale fire events during the late fifteenth and late sixteenth centuries. Shifts in the vegetation community composition and structure accompanied these fires, with Pinus and Picea decreasing in relative abundance and Poaceae increasing in relative abundance following the fire events. During the LIA, the vegetation change and lacustrine geochemical response was most directly influenced by the occurrence of catchment-scale fires, not regional hydroclimate.

scholarly journals Mineralogy, mineral chemistry and thermobarometry of post-mineralization dykes of the Sungun Cu–Mo porphyry deposit (Northwest Iran)

2020 ◽  
Vol 12 (1) ◽  
pp. 764-790
Author(s):  
Amin Allah Kamali ◽  
Mohsen Moayyed ◽  
Nasir Amel ◽  
Fadaeian Mohammad ◽  
Marco Brenna ◽  
...  
Keyword(s):  
Active Continental Margin ◽  
Mineral Chemistry ◽  
Quartz Diorite ◽  
Alkaline Magmatism ◽  
Porphyry Deposit ◽  
Average Percentage ◽  
The North ◽  
Northwestern Iran ◽  
Subduction System ◽  
Late Stages

AbstractThe Sungun copper–molybdenum porphyry deposit is located in the north of Varzaghan, northwestern Iran. The Sungun quartz-monzonite is the oldest mineralized intrusive body in the region and was emplaced during the Early Miocene. Eight categories of the late and unmineralized dykes, which include quartz diorite, gabbrodiorite, diorite, dacite, microdiorite and lamprophyre (LAM), intrude the ore deposit. The main mineral phases in the dykes include plagioclase, amphibole and biotite, with minor quartz and apatite and secondary chlorite, epidote, muscovite and sericite. The composition of plagioclase in the quartz diorite dykes (DK1a, DK1b and DK1c) varies from albite-oligoclase to andesine and oligoclase to andesine; in the diorite, it varies from andesine to labradorite; in the LAM, from albite to oligoclase; and in the microdiorite (MDI), it occurs as albite. Amphibole compositions are consistent with classification as hornblende or calcic amphibole. Based on their AlIV value (less than 1.5), amphibole compositions are consistent with an active continental margin affinity. The average percentage of pistacite (Ps) in epidotes formed from alteration of plagioclase and ferromagnesian minerals is 27–23% and 25–30%, respectively. Thermobarometric studies based on amphibole and biotite indicate approximate dyke crystallization temperature of 850–750℃, pressure of 231–336 MPa and high fO2 (>nickel-nickel-oxide buffer). The range of mineral compositions in the postmineralization dyke suite is consistent with a genetic relationship with the subduction of the Neotethys oceanic crust beneath the continental crust of the northwest part of the Central Iranian Structural Zone. Despite the change from calc-alkaline to alkaline magmatism, the dykes are likely related to the late stages of magmatic activity in the subduction system that also generated the porphyry deposit.

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