Paleoclimatic Reconstruction

An a M a t i n , T a j a n a K r i þ k a , V a n j a J u r i š i ü , N. V o ü a , T e a B r l e k S a vi ü , N. B i l a n d ž i j a Izvorni znanstveni þlanak Primljeno: 15. sijeþanj 2009. SAŽETAK Cilj ovog rada bio je istražiti utjecaj procesa uparavanja kao hidrotermiþke dorade i sušenja na dimenzije zrna kukuruza (dužina, širina i debljina). Istraživanja su provedena tijekom tri vegetacijske sezone (2002., 2003. i 2004. godina) na hibridima Bc 4982, Bc 462, Bc Jumbo, Florencia i Stefania uzgojenih na niskoj i visokoj razini agrotehnike. Navedeni hibridi su nakon berbe podvrgnuti procesu uparavanja (0,5 bara u vremenu od 10 minuta) nakon þega su sušeni i to na þetiri temperature (70 °C, 90 °C, 110 °C, 130 °C). Uz dimenzije utvÿena su i fizikalna svojstva gustoüa, volumen i sferiþnost zrna kukuruza. Dobiveni rezultati pokazuju da postoje znaþajne razlike u dimenzijama zrna kukuruza prije i nakon procesa uparavanja kao i izmeÿu uzoraka tretitanih razliþitim temperaturama sušenja.

Cilj ovog rada bio je istražiti mineraloške, geokemijske, pedofizikalne i mikromorfološke značajke tla u vršnom dijelu pedosedimentnog kompleksa Savudrija. Terenskim istraživanjima uzeto je šest uzoraka tla, po jedan iz svakog od šest najviših horizonata, koja su podvrgnuta detaljnom opisu morfoloških svojstava. Laboratorijskim istraživanjima na uzorcima je napravljena detaljna kemijska analiza, fizikalno-kemijska analiza tla, uključujući CEC i saturaciju bazama, granulometrija, analiza željeza i mangana topivih u ditionitu i oksalatu, analiza mineralnog sastava, primjenom rendgenske difrakcije na prahu, određivanje starosti metodom optički (OSL) te infracrveno (IRSL) stimulirane luminiscencije te analiza mikromorfoloških preparata. Najvažniji zaključci ovog rada su: (1) Analizirani vršni dio pedosedimentnog kompleksa predstavljala su dva superponirana lesna supstrata unutar kojih su razvijena (paleo)tla. (2) Korištenjem geokemijskih omjera Sm/Nd te La/Ce, utvrđeno je isto podrijetl...

В настоящей работе приводятся результаты синтеза соединений двойных K-Ca карбонатов при атмосферном давлении в закрытых графитовых капсулах. В качестве исходных веществ использовались смеси K 2 CO 3 и CaCO 3 , соответствующие по составу стехиометрии K 2 Ca(CO 3) 2 и K 2 Ca 2 (CO 3) 3. Низкотемпературная модификация K 2 Ca(CO 3) 2 получена путем твердофазного синтеза при 500°С в течение 96 ч. Высокотемпературная модификация K 2 Ca(CO 3) 2 , а также соединение K 2 Ca 2 (CO 3) 3 получены двумя способами: путем твердофазного синтеза при 600°С в течение 72 ч, а также в ходе охлаждения расплава с 830 до 650°С в течение 30 мин. Полученные карбонаты изучены методом

AbstrAct—The Water Canyon Paleoindian site near Socorro, New Mexico, is directly associated with an extensive buried wetland deposit, or black mat. This landscape-scale feature, which was extant across the late Pleistocene–early Holocene transition, represents the remains of a wetland resource that, during the early Holocene, may have served as an ecological refugium for flora, fauna and Paleoindian groups as other regional water sources disappeared. Today the organic-rich deposit has proved to be an important proxy data archive for environmental , climatic and archaeological reconstructions. Our recent paleoenvironmental reconstruction efforts at the site have focused largely on the period from ~8300 to 11,100 radiocarbon years ago, and have generated a range of proxy data, including dated pollen profiles, stable carbon isotope values, charcoal species identifications, and both faunal and macrobotanical remains. The pollen data currently provide the most robust basis for our paleoenvironmental reconstruction and, together with our chronometric data, affirm that the black-mat forming wetland served as a persistent place of ecological diversity. These findings provide us with provocative glimpses of past environments in a heretofore largely understudied region of the American Southwest, and add to a growing body of Southwest reconstructions that will ultimately enable researchers to compare paleoenvironments and paleoclimates at both local and regional scales.

Представлены результаты исследований первичных биологических аэрозолей (пыльцевые спектры и водоросли) в атмосферных осадках, выпадавших на территории Алтайского биосферного заповедника (Республика Алтай, Россия) с июля по октябрь 2017 года. В проанализированных пробах было интерпретировано 28 таксонов пыльцевых зерен и водорослей. Анализ обратных траекторий движения воздушных масс, рассчитанных с помощью модели HYSPLIT, позволил определить основные регионы поступления пыльцевых зерен и водорослей на территорию Алтайского биосферного заповедника за указанный промежуток времени.

Climate and vegetation of the antique Tanais (the 3rd century BC – 5th century AD) based on the data of paleopedological and paleobotanic analyses

The chrono-sequence of paleosols buried under stone buildings of the antique Tanais related to different chrono-intervals within the time of the city’s existence (from the second half of the 3rd century BC to the middle or the end of the 5th century AD) was studied using paleopedological, biomorphic and palynological analyzes; and reconstruction of climate and vegetation was proposed. The climate of the initial period of life of the city was similar or slightly more humid than current conditions. Morphological and physicochemical properties of paleosols dated back to the turn of the 3rd–2nd and the second half of the 2nd centuries BC are similar to those of modern ordinary chernozems. Palynological spectra indicate the development of meadowsteppe vegetation, and microbiomorphic analysis shows the richness of the flora of surrounding the city spaces. There is a noticeable share of cultural cereals as well as ruderal species in the pollen spectra. Reed plants and coniferous trees were widely used for economic needs. The significant climatic aridization occurred at the turn of the era, i.e., during the 1st century BC – 1st century AD. In the paleosols dated back to the 1st century AD, the maximum values of carbonates and gypsum content, pH, maximum share of exchangeable magnesium and sodium in the composition of exchange bases were detected. Spore-pollen spectra are xerophytic, they do not contain pollen of broad-leaved trees, the species composition of herbs is poor, the Chenopodiaceae and Graminea plants predominate. The share of pollen of cultural cereals is noticeably lower than previously. According to archaeological data, the city experienced a devastating ravage, a series of fires and destruction and was restored very slowly. Palinological spectra of the 4th century AD are characteristic for the steppe conditions, and also the share of pollen of pine increases, which can serve as an indicator of its expansion in the floodplain forests in the middle reaches of the Don River. The share of species associated with anthropogenic impact on the vegetation cover is lower than that for the early period of Tanais functioning and prosperity, which may indicate an incomplete recovery of past economic activity.

The paleoecological conditions of the Tanais antique city functioning were
considered starting with the 3rd century BC and ending at the 5th century AD. For the reconstruction
of paleoclimatic changes in the mentioned period the palynological and paleopedological
data for the region near the Azov Sea, in particular, and for the steppe zone of the European part
of Russia as a whole were used. The antique city was located on the right bank of the river Tanais
(Don) near its confluence with the Azov Sea and exercised trade and economic relations
with the barbarian (nomadic) population inhabited the steppes near the Don River and the Azov
Sea. It is shown that the foundation in the 3rd century BC and formation of Tanais in the 2nd century
BC took place in relatively comfortable and favorable climatic conditions comparable to
those of the modern period. The most devastating conquest and destruction of the city by the
Bosporus King Polemon was at the end of the 1st century BC during the peak of climatic aridization
when Tanais could survive the economic crisis. After more than a century in the revived city
the composition of the population and plan of housing were changed. It is possible that at the
same time the sea receded further from the city, the river changed its course and the city lost a
part of seaport. Climatic conditions since the second half of the 2nd till the middle or end of the
4th centuries AD were characterized as favorable. Another wave of aridity was dated to the border
between the 4th and 5th centuries AD or to first half of the 5th century AD. In the era of the
Great Migration of people, in the end of the 5th century AD, the existence of the city ended.