نتایج جستجو برای: microfossil

تعداد نتایج: 309  

Journal: Geopersia 2016

The present article is a review of a palaeobiogeographic analysis of Jurassic Ostracods from East Africa, India and Madagascar and includes also some general remarks on palaeobiogeography, biodiversity and Ostracod ecology.The palaeobiogeographic study shows the high significance of this microfossil group for the reconstruction of palaeogeographic processes, particularly plate tectonic developm...

Journal: :Palaeobiodiversity and Palaeoenvironments 2022

Abstract The Hagen-Balve Reef Complex of the northern Rhenish Massif, Germany, is one best examples for globally widespread Givetian to Frasnian reefs. At its eastern end, in Hönne Valley, it reaches up 1000 metres thickness. In general, there limited knowledge concerning faunas and palaeoecology initial reef phases. A unique section at Binolen exposes sharp boundary between underlying, silicic...

Journal: :Current Biology 2014
Gernot Glöckner Norbert Hülsmann Michael Schleicher Angelika A. Noegel Ludwig Eichinger Christoph Gallinger Jan Pawlowski Roberto Sierra Ursula Euteneuer Loic Pillet Ahmed Moustafa Matthias Platzer Marco Groth Karol Szafranski Manfred Schliwa

BACKGROUND Rhizaria are a major branch of eukaryote evolution with an extensive microfossil record, but only scarce molecular data are available. The rhizarian species Reticulomyxa filosa, belonging to the Foraminifera, is free-living in freshwater environments. In culture, it thrives only as a plasmodium with thousands of haploid nuclei in one cell. The R. filosa genome is the first foraminife...

2016
Luke C. Strotz Briony L. Mamo Dale Dominey-Howes

The sedimentary record, and associated micropalaeontological proxies, is one tool that has been employed to quantify a region's tropical cyclone history. Doing so has largely relied on the identification of allochthonous deposits (sediments and microfossils), sourced from deeper water and entrained by tropical cyclone waves and currents, in a shallow-water or terrestrial setting. In this study,...

2016
John A. Chamberlain Rebecca B. Chamberlain James O. Brown

Sphaeromorphic algal cysts, most probably of the prasinophyte Tasmanites, and acanthomorphic acritarch vesicles, most probably Solisphaeridium, occur in a single 20 cm thick bed of micritic limestone in the lower part of the Middle Devonian (Givetian) Tully Formation near Lock Haven, Pennsylvania. Specimens are composed of authigenic calcite and pyrite crystals about 5–10 μm in length. Some spe...

2012
PEDRO CERMEÑO EMILIO MARAÑÓN OSCAR E. ROMERO Roger Harris

The high temporal resolution of the marine microfossil record makes it possible to explore how microbial communities responded to abrupt climate changes in the past. We analysed changes in species richness and total abundance of marine diatoms in sedimentary records from the Mauritanian upwelling system and the Panama Basin spanning the last 100 000 years. The analysis shows instances of commun...

2017
Christine Heim Nadia-Valérie Quéric Danny Ionescu Nadine Schäfer Joachim Reitner

Stromatolitic iron-rich structures have been reported from many ancient environments and are often described as Frutexites, a cryptic microfossil. Although microbial formation of such structures is likely, a clear relation to a microbial precursor is lacking so far. Here we report recent iron oxidizing biofilms which resemble the ancient Frutexites structures. The living Frutexites-like biofilm...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2006
Andrew Sluyter Gabriela Dominguez

A sedimentary pollen sequence from the coastal plain of Veracruz, Mexico, demonstrates maize cultivation by 5,000 years ago, refining understanding of the geography of early maize cultivation. Methodological issues related to bioturbation involved in dating that record combine with its similarity to a pollen sequence from the coastal plain of Tabasco, Mexico, to suggest that the inception of ma...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه شهید بهشتی - دانشکده علوم زمین 1383

چکیده ندارد.

2013
Jonathan P. Warnock Peter T. Doran

The McMurdo Dry Valleys of Antarctica are a unique environment characterized by extreme lows in temperature and precipitation, which supports a low diversity microbial and multicellular fauna and flora. Terrestrial biomass is largely limited to soil microbes and mosses, while perennially ice-covered lakes host aerobic and anaerobic microbial communities, algae, and a low diversity eukaryotic fa...

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