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Pollen Zone
Pollen zones are a system of subdividing the Last Glacial Period and Holocene paleoclimate using the data from pollen cores. The sequence provides a global chronological structure to a wide variety of researchers, such as geologists, climatologists, geographers and archaeologists, who study the physical and cultural environment of the last 15,000 years. 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. 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 pro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Helianthus Annuus Pollen 1
''Helianthus'' () is a genus comprising around 70 species of annual and perennial flowering plants in the daisy family Asteraceae commonly known as sunflowers. Except for three South American species, the species of ''Helianthus'' are native to North America and Central America. The best-known species is the common sunflower (''Helianthus annuus''). This and other species, notably Jerusalem artichoke (''H. tuberosus''), are cultivated in temperate regions and some tropical regions, as food crops for humans, cattle, and poultry, and as ornamental plants. The species ''H. annuus'' typically grows during the summer and into early fall, with the peak growth season being mid-summer. Several perennial ''Helianthus'' species are grown in gardens, but have a tendency to spread rapidly and can become aggressive. On the other hand, the whorled sunflower, ''Helianthus verticillatus'', was listed as an endangered species in 2014 when the U.S. Fish and Wildlife Service issued a final rule p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iron Age
The Iron Age () is the final epoch of the three historical Metal Ages, after the Chalcolithic and Bronze Age. It has also been considered as the final age of the three-age division starting with prehistory (before recorded history) and progressing to protohistory (before written history). In this usage, it is preceded by the Stone Age (subdivided into the Paleolithic, Mesolithic and Neolithic) and Bronze Age. These concepts originated for describing Iron Age Europe and the ancient Near East. In the archaeology of the Americas, a five-period system is conventionally used instead; indigenous cultures there did not develop an iron economy in the pre-Columbian era, though some did work copper and bronze. Indigenous metalworking arrived in Australia with European contact. Although meteoric iron has been used for millennia in many regions, the beginning of the Iron Age is defined locally around the world by archaeological convention when the production of Smelting, smelted iron (espe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Park Tundra
Park tundra was a plant community that occurred in northwestern Europe after the last ice age ended. History The community was similar to that found today at the boundary between tundra and taiga in Siberia: species included the dwarf birch and the least willow. Park tundra stretched as far south as the Alps and the Pyrenees. Park tundra was common during the colder post-glacial periods, such as the Older Dryas (12,000-10,000 BCE) and the Younger Dryas The Younger Dryas (YD, Greenland Stadial GS-1) was a period in Earth's geologic history that occurred circa 12,900 to 11,700 years Before Present (BP). It is primarily known for the sudden or "abrupt" cooling in the Northern Hemisphere, when the ... (8,800-8,300 BCE). References Tundra Flora of Europe {{geo-term-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Allerød Oscillation
Allerød may refer to: * Allerød Municipality, a municipality in Denmark ** Lillerød, also called ''Allerød'', seat of the municipality ** Allerød station, a railway station in the Danish town * Allerød oscillation, a climatic period at the end of the last glaciation * Allerød FK, a football club in Lillerød {{disambig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tundra
In physical geography, a tundra () is a type of biome where tree growth is hindered by frigid temperatures and short growing seasons. There are three regions and associated types of tundra: #Arctic, Arctic, Alpine tundra, Alpine, and #Antarctic, Antarctic. Tundra vegetation is composed of dwarf shrubs, Cyperaceae, sedges, Poaceae, grasses, mosses, and lichens. Scattered trees grow in some tundra regions. The ecotone (or ecological boundary region) between the tundra and the forest is known as the tree line or timberline. The tundra soil is rich in nitrogen and phosphorus. The soil also contains large amounts of biomass and decomposed biomass that has been stored as methane and carbon dioxide in the permafrost, making the tundra soil a carbon sink. As global warming heats the ecosystem and causes soil thawing, the permafrost carbon cycle accelerates and releases much of these soil-contained greenhouse gases into the atmosphere, creating Climate change feedback, a feedback cycle t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Younger Dryas
The Younger Dryas (YD, Greenland Stadial GS-1) was a period in Earth's geologic history that occurred circa 12,900 to 11,700 years Before Present (BP). It is primarily known for the sudden or "abrupt" cooling in the Northern Hemisphere, when the North Atlantic Ocean cooled and annual air temperatures decreased by ~ over North America, in Europe and up to in Greenland, in a few decades. Cooling in Greenland was particularly rapid, taking place over just 3 years or less. At the same time, the Southern Hemisphere experienced warming. This period ended as rapidly as it began, with dramatic warming over ~50 years, the transition from the glacial Pleistocene epoch into the current Holocene. The Younger Dryas onset was not fully synchronized; in the tropics, the cooling was spread out over several centuries, and the same was true of the early-Holocene warming. Even in the Northern Hemisphere, temperature change was highly seasonal, with much colder winters, cooler springs, yet no cha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Upper Palaeolithic
The Upper Paleolithic (or Upper Palaeolithic) is the third and last subdivision of the Paleolithic or Old Stone Age. Very broadly, it dates to between 50,000 and 12,000 years ago (the beginning of the Holocene), according to some theories coinciding with the appearance of behavioral modernity in early modern humans. It is followed by the Mesolithic. Anatomically modern humans (i.e. ''Homo sapiens'') are believed to have emerged in Africa around 300,000 years ago. It has been argued by some that their ways of life changed relatively little from that of archaic humans of the Middle Paleolithic, until about 50,000 years ago, when there was a marked increase in the diversity of artefacts found associated with modern human remains. This period coincides with the most common date assigned to expansion of modern humans from Africa throughout Asia and Eurasia, which may have contributed to the extinction of the Neanderthals. The Upper Paleolithic has the earliest known evide ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mesolithic
The Mesolithic (Ancient Greek language, Greek: μέσος, ''mesos'' 'middle' + λίθος, ''lithos'' 'stone') or Middle Stone Age is the Old World archaeological period between the Upper Paleolithic and the Neolithic. The term Epipaleolithic is often used synonymously, especially for outside northern Europe, and for the corresponding period in Epipaleolithic Near East, the Levant and Epipaleolithic Caucasus, Caucasus. The Mesolithic has different time spans in different parts of Eurasia. It refers to the final period of hunter-gatherer cultures in Europe and the Middle East, between the end of the Last Glacial Maximum and the Neolithic Revolution. In Europe it spans roughly 15,000 to 5,000 Before Present, BP; in the Middle East (the Epipalaeolithic Near East) roughly 20,000 to 10,000 Before Present, BP. The term is less used of areas farther east, and not at all beyond Eurasia and North Africa. The type of culture associated with the Mesolithic varies between areas, b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boreal (age)
In paleoclimatology of the Holocene, the Boreal was the first of the Blytt–Sernander sequence of north European climatic phases that were originally based on the study of Danish peat bogs, named for Axel Blytt and Rutger Sernander, who first established the sequence. In peat bog sediments, the Boreal is also recognized by its characteristic pollen zone. It was preceded by the Younger Dryas, the last cold snap of the Pleistocene, and followed by the Atlantic, a warmer and moister period than our most recent climate. The Boreal, transitional between the two periods, varied a great deal, at times having within it climates like today's. Subdividing the Boreal Subsequent to the original Blytt-Sernander scheme, the first stage of the Boreal was divided off as a Pre-boreal transitional phase, followed by the Boreal proper. Some current schemes based on pollen zones also distinguish a pre-Boreal (pollen zone IV), an early Boreal (pollen zone V) and a late Boreal (pollen zone VIa, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neolithic
The Neolithic or New Stone Age (from Ancient Greek, Greek 'new' and 'stone') is an archaeological period, the final division of the Stone Age in Mesopotamia, Asia, Europe and Africa (c. 10,000 BCE to c. 2,000 BCE). It saw the Neolithic Revolution, a wide-ranging set of developments that appear to have arisen independently in several parts of the world. This "Neolithic package" included the History of agriculture, introduction of farming, domestication of animals, and change from a hunter-gatherer lifestyle to one of sedentism, settlement. The term 'Neolithic' was coined by John Lubbock, 1st Baron Avebury, Sir John Lubbock in 1865 as a refinement of the three-age system. The Neolithic began about 12,000 years ago, when farming appeared in the Epipalaeolithic Near East and Mesopotamia, and later in other parts of the world. It lasted in the Near East until the transitional period of the Chalcolithic (Copper Age) from about 6,500 years ago (4500 BCE), marked by the development ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atlantic (period)
The Atlantic in palaeoclimatology was the warmest and moistest Blytt–Sernander period, pollen zone and chronozone of Holocene northern Europe. The climate was generally warmer than today. It was preceded by the Boreal, with a climate similar to today's, and was followed by the Subboreal, a transition to the modern. Because it was the warmest period of the Holocene, the Atlantic is often referenced more directly as the Holocene climatic optimum, or just climatic optimum. Subdividing the Atlantic The Atlantic is equivalent to pollen zone VII. Sometimes a Pre-atlantic or early Atlantic is distinguished, on the basis of an early dividing cold snap. Other scientists place the Atlantic entirely after the cold snap, assigning the latter to the Boreal. The period is still in the process of definition. Dating Beginning of the Atlantic period It is a question of definition and the criteria: Beginning with the temperatures, as derivable from Greenland ice core data, it is possible ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
