Helianthus annuus pollen

Pollen zones are a system of subdividing late Pleistocene and early Holocene paleoclimate using the data from pollen cores. The sequence provides a global chronological structure to a wide variety of scientists, such as geologists, climatologisists, geographists and archaeologists, who study the physical and cultural environment of the last 15,000 years. Image File history File links Download high resolution version (1228x960, 246 KB) Scanning electron microscope image of pollen grains from Helianthus annuus (common sunflower). ... Image File history File links Download high resolution version (1228x960, 246 KB) Scanning electron microscope image of pollen grains from Helianthus annuus (common sunflower). ... The Pleistocene Epoch is part of the geologic timescale. ... The Holocene epoch is a geological period that extends from the present back about 10,000 radiocarbon years. ... Pollen cores being taken at Fort Bragg, North Carolina. ... Geology (from Greek γη- (ge-, the earth) and λογος (logos, word, reason)) is the science and study of the Earth, its composition, structure, physical properties, history and the processes that shape it. ... Climatology is the study of climate, and is a branch of the atmospheric sciences. ... Map of the Earth ( Medium) ( Large 2 MB) Wikimedia Commons has media related to: Geography Table of geography, hydrography, and navigation, from the 1728 Cyclopaedia. ... Archaeology or sometimes in American English archeology (from the Greek words αρχαίος = ancient and λόγος = word/speech) is the study of human cultures through the recovery, documentation and analysis of material remains, including architecture, artefacts, biofacts, human remains, and landscapes. ...

History

The palynological aspects of the system were first investigated extensively by the Swedish palynologist Lennart von Post in the years before the First World War. By analysing pollen in core samples taken from peat bogs, von Post noticed that different plant species were represented in bands through the cores. Pollen under microscope Palynology is the science that studies contemporary and fossil palynomorphs, including pollen, spores, dinoflagellate cysts, acritarchs, chitinozoans and scolecodonts, together with particulate organic matter (POM) and kerogen found in sedimentary rocks and sediments. ... Combatants Allies: • Serbia, • Russia, • France, • Romania, • Belgium, • British Empire and Dominions, • United States, • Italy, • ...and others Central Powers: • Germany, • Austria-Hungary, • Ottoman Empire, • Bulgaria Casualties 5 million military, 3 million civilian (full list) 3 million military, 3 million civilian (full list) World War I, also known as the First World... A core sample is a cylindrical section of a naturally occurring medium consistent enough to hold a layered structure. ... Peat in Lewis, Scotland Peat is an accumulation of partially decayed vegetable matter. ...

The differing species and differing quantities of the same species are caused by changes in climate. Von Post was able to confirm the Blytt-Sernander climatic sequence showing fluctuations between warmer and colder periods across thousands of years. He used local peat sequences combined with varve dating to produce a regional climatic chronology for Scandinavia. The Blytt-Sernander classification, or sequence, is a series of north European climatic periods or phases based on the study of Danish peat bogs by Axel Blytt (1876) and Rutger Sernander (1908). ... A varve is an annual layer of sediment or sedimentary rock. ... See also the Nordic countries. ...

In 1940 Harry Godwin began applying von Post's methods to pollen cores from the British Isles to produce the wider European sequence accepted today. It basically expanded the Blytt-Sernander further into the late Pleistocene and refined some of its periods. Following the Second World War, the technique spread to the Americas. Professor Sir Harry Godwin FRS, (9 May 1901 - 12 August 1985) was a prominent English botanist and ecologist of the 20th century. ... This article may contain original research or unverified claims. ... The Pleistocene Epoch is part of the geologic timescale. ... Combatants Allies: • Poland, • UK & Commonwealth, • France/Free France, • Soviet Union, • USA, • China, ...and others• Axis: • Germany, • Italy, • Japan, • ...and others Casualties Military dead: 17 million Civilian dead: 33 million Total: 50 million Full list Military dead: 8 million Civilian dead: 4 million Total: 12 million Full list World War II...

Currently scientists are focusing a repertory of several different methods on core samples in peat, ice, lake and ocean bottoms, and sediments to achieve "high resolution" dating not possible to only one method: Carbon dating, Dendrochronology, isotope ratios on a number of gases, studies of insects and molluscs, and others. While often doubting the utility of the modified Bytt-Sernander, they seem to confirm and expand it all the more. A core sample is a cylindrical section of a naturally occurring medium consistent enough to hold a layered structure. ... Radiocarbon dating is the use of the naturally occurring isotope of carbon-14 in radiometric dating to determine the age of organic materials, up to ca. ... Pinus taeda Cross section showing annual rings, Cheraw, South Carolina Pine stump showing growth rings Dendrochronology or tree-ring dating is the method of scientific dating based on the analysis of tree ring patterns. ... Oxygen isotope ratio cycles are cyclical variations in the ratio of the mass of Oxygen with an atomic weight of 18 to the mass of Oxygen with an atomic weight of 16 present in calcite of the oceanic floor as determined by core samples. ...

Notes on the sequence table

At present nine main pollen zones, I-IX, are defined, based on the work of J. Iverson, published in 1954. These are matched to period names called "biostratigraphic divisions" in the table, which were defined for Denmark by Iverson based on layers in the peat bogs. They represent climatic and biological zones in the peat.

Others have used these names in different senses, such as the 1974 chronozones of J. Mangerud. The sequences in Germany and Sweden are not exactly the same as those in Denmark, inviting scientists there to use the names still differently or make other definitions. Moreover, the names are apt to be used interchangeably for glacials, interglacials, stadial, interstadials, or oscillations, leading some scientists to deplore the lack of system.

The system of the table below covers from around 13,000 BC to the modern day. Dates, given in years BC, are best viewed as being based on uncalibrated C-14 dates, which, when calibrated, would result in much earlier BC dates. For example, an Older Dryas start date of 10,000 BC translates roughly into an uncalibrated BP date of 12,000. Calibrated, that becomes 14,000 BP, 12,000 BC. To obtain quick, on-line calibrations, you may use CalPal.

The dates in the table correspond relatively well to more modern dates for the earlier periods. Larger discrepancies begin at the end of the Boreal. More, and more modern, details on the dating of the periods are given under the article for each one.

The archaeological periods listed only apply to north Europe, and do so approximately. For example, there is no uniform chronozone, "the Bronze Age", which would apply globally or even be of the same dates between north and south Europe.

The geological stages listed are only defined for the British Isles. Scientists use different names for north Europe, south Europe and other regions. However, they are cross-correlated in the articles for the ones listed.

In contrast to glacial periods, these pollen zones are being used to apply globally, with but few exceptions. It is acceptable, for example, to refer to the "Younger Dryas" of Antarctica, which has no pollen of its own. A few scientists disapprove of such uses.

Sequence table

Iron Age Axe found on Gotland This article is about the archaeological period known as the Iron Age, for the mythological Iron Age see Iron Age (mythology). ... The Flandrian interglacial or stage is the name given by geologists and archaeologists in the British Isles to the first, and so far only, stage of the Holocene, covering the period from around 10,000 years ago when the last ice age ended to the present day. ... The Bronze Age is a period in a civilizations development when the most advanced metalworking has developed the techniques of smelting copper from natural outcroppings and alloys it to cast bronze. ... Iron Age Axe found on Gotland This article is about the archaeological period known as the Iron Age, for the mythological Iron Age see Iron Age (mythology). ... Canopy The Atlantic in palaeoclimatology was the warmest and most moist Blytt-Sernander period, pollen zone and chronozone of Holocene north Europe. ... The Neolithic (or New Stone Age) was a period in the development of human technology that is traditionally the last part of the Stone Age. ... The Boreal in paleoclimatology was the first Blytt-Sernander period, pollen zone and chronozone of Holocene north Europe. ... The Mesolithic (Greek mesos=middle and lithos=stone or the Middle Stone Age) is the period between the Paleolithic and Neolithic periods. ... The Boreal in paleoclimatology was the first Blytt-Sernander period, pollen zone and chronozone of Holocene north Europe. ... The Upper Paleolithic or Palaeolithic is the third and last subdivision of the Paleolithic or Old Stone Age as it is understood in Europe, Africa and Asia. ... The Mesolithic (Greek mesos=middle and lithos=stone or the Middle Stone Age) is the period between the Paleolithic and Neolithic periods. ... The Devensian glaciation is a name for an ice age period which occurred between 120,000 and 10,000 years ago. ... Three temperature records, the GRIP one clearly showing the Younger Dryas event at around 11 kyr BP The Younger Dryas stadial, named after the alpine / tundra wildflower Dryas octopetala, and also referred to as the Big Freeze [1], was a brief (approximately 1300 +/- 70year [1]) cold climate period following the... In physical geography, tundra is an area where the tree growth is hindered by low temperatures and OMFG. The term tundra comes from Kildin Sami tū̄ndra, the genitive of tundar, treeless plain. There are three types of tundra: Arctic tundra, Antarctic tundra, and alpine tundra. ... The Allerød period is a part of a temperature oscillation towards the end of the last Ice Age in Europe, where temperatures in the Northern Atlantic region rose from glacial to almost present day level in the Bølling and Allerød periods and returned to glacial levels in... The Older Dryas was a cold, dry Blytt-Sernander period and pollen zone of North Europe dated to roughly 14,000-13,600 BP calibrated, 12,000-11,700 uncalibrated. ... The Bølling Oscillation was a brief warm period that occurred during the final stages of the last glaciation of Europe. ... The Oldest Dryas is a climatic period, which occurred during the coldest stadial after the Weichselian glaciation in north Europe. ... The Upper Paleolithic or Palaeolithic is the third and last subdivision of the Paleolithic or Old Stone Age as it is understood in Europe, Africa and Asia. ...

External links

• Reconsidering the geochronological framework of Lateglacial hunter-gatherer colonization of southern Scandinavia
• Wansleben Salt Lake