The Holocene is the current geological epoch, beginning approximately 11,700 years ago. It follows the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene together form the Quaternary period. The Holocene is an interglacial period within the ongoing glacial cycles of the Quaternary, and is equivalent to Marine Isotope Stage 1.
The Younger Dryas 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 ~3 °C (5.4 °F) over North America, 2–6 °C (3.6–10.8 °F) in Europe and up to 10 °C (18 °F) 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, which transitioned the Earth from the glacial Pleistocene epoch into the current Holocene.
A megatsunami is a very large wave created by a large, sudden displacement of material into a body of water.
A loess is a clastic, predominantly silt-sized sediment that is formed by the accumulation of wind-blown dust. Ten percent of Earth's land area is covered by loesses or similar deposits.
A raised beach, coastal terrace, or perched coastline is a relatively flat, horizontal or gently inclined surface of marine origin, mostly an old abrasion platform which has been lifted out of the sphere of wave activity. Thus, it lies above or under the current sea level, depending on the time of its formation. It is bounded by a steeper ascending slope on the landward side and a steeper descending slope on the seaward side. Due to its generally flat shape, it is often used for anthropogenic structures such as settlements and infrastructure.
Carolina bays are elliptical to circular depressions concentrated along the East Coast of the United States within coastal New York, New Jersey, Delaware, Maryland, Virginia, North Carolina, South Carolina, Georgia, and north Florida. In Maryland, they are called Maryland basins. Within the Delmarva Peninsula, they and other coastal ponds are also called Delmarva bays.
Tollmann's bolide hypothesis is a hypothesis presented by Austrian palaeontologist Edith Kristan-Tollmann and geologist Alexander Tollmann in 1994. The hypothesis postulates that one or several bolides struck the Earth around 7640 ± 200 years BCE, and a much smaller one approximately 3150 ± 200 BCE. The hypothesis tries to explain early Holocene extinctions and possibly legends of the Universal Deluge.
Aeolian processes, also spelled eolian, pertain to wind activity in the study of geology and weather and specifically to the wind's ability to shape the surface of the Earth. Winds may erode, transport, and deposit materials and are effective agents in regions with sparse vegetation, a lack of soil moisture and a large supply of unconsolidated sediments. Although water is a much more powerful eroding force than wind, aeolian processes are important in arid environments such as deserts.
The Black Sea deluge is the best known of three hypothetical flood scenarios proposed for the Late Quaternary history of the Black Sea. One other flood scenario proposes a rapid, even catastrophic, rise in sea level of the Black Sea.
Lake Mungo is a dry lake located in New South Wales, Australia. It is about 760 km due west of Sydney and 90 km north-east of Mildura. The lake is the central feature of Mungo National Park, and is one of seventeen lakes in the World Heritage listed Willandra Lakes Region. Many important archaeological findings have been made at the lake, most significantly the discovery of the remains of Mungo Man, the oldest human remains found in Australia, Mungo Woman, the oldest human remains in the world to be ritually cremated and as the location of the Lake Mungo geomagnetic excursion, the first convincing evidence that Geomagnetic excursions are a geomagnetic phenomenon rather than sedimentological.
The Fenambosy Chevron is one of four chevron-shaped land features on the southwest coast of Madagascar, near the tip of Madagascar, 180 meters (590 ft) high and 5 kilometres (3.1 mi) inland. Chevrons such as Fenambosy have been hypothesized as providing evidence of "megatsunamis" caused by comets or asteroids crashing into Earth. However, the megatsunami origin of the Fernambosy and other chevrons has been challenged by other geologists and oceanographers.
The Burckle crater is an undersea topographic feature about 29 kilometres in diameter in the southwestern Indian Ocean. A team of Earth scientists called the Holocene Impact Working Group proposes the feature to be an impact crater; these claims are disputed by other geologists.
The 1958 Lituya Bay earthquake occurred on PST with a moment magnitude of 7.8 to 8.3 and a maximum Mercalli intensity of XI (Extreme). The strike-slip earthquake took place on the Fairweather Fault and triggered a rockslide of 30 million cubic meters and about 90 million tons into the narrow inlet of Lituya Bay, Alaska. The impact was heard 80 kilometers (50 mi) away, and the sudden displacement of water resulted in a megatsunami that washed out trees to a maximum elevation of 524 meters at the entrance of Gilbert Inlet. This is the largest and most significant megatsunami in modern times; it forced a re-evaluation of large-wave events and the recognition of impact events, rockfalls, and landslides as causes of very large waves.
North African climate cycles have a unique history that can be traced back millions of years. The cyclic climate pattern of the Sahara is characterized by significant shifts in the strength of the North African Monsoon. When the North African Monsoon is at its strongest, annual precipitation and consequently vegetation in the Sahara region increase, resulting in conditions commonly referred to as the "green Sahara". For a relatively weak North African Monsoon, the opposite is true, with decreased annual precipitation and less vegetation resulting in a phase of the Sahara climate cycle known as the "desert Sahara".
Marine Isotope Stage 5 or MIS 5 is a marine isotope stage in the geologic temperature record, between 130,000 and 80,000 years ago. Sub-stage MIS 5e corresponds to the Last Interglacial, also called the Eemian or Sangamonian, the last major interglacial period before the Holocene, which extends to the present day. Interglacial periods which occurred during the Pleistocene are investigated to better understand present and future climate variability. Thus, the present interglacial, the Holocene, is compared with MIS 5 or the interglacials of Marine Isotope Stage 11.
The African humid period was a climate period in Africa during the late Pleistocene and Holocene geologic epochs, when northern Africa was wetter than today. The covering of much of the Sahara desert by grasses, trees and lakes was caused by changes in the Earth's axial tilt; changes in vegetation and dust in the Sahara which strengthened the African monsoon; and increased greenhouse gases. During the preceding Last Glacial Maximum, the Sahara contained extensive dune fields and was mostly uninhabited. It was much larger than today, and its lakes and rivers such as Lake Victoria and the White Nile were either dry or at low levels. The humid period began about 14,600–14,500 years ago at the end of Heinrich event 1, simultaneously to the Bølling–Allerød warming. Rivers and lakes such as Lake Chad formed or expanded, glaciers grew on Mount Kilimanjaro and the Sahara retreated. Two major dry fluctuations occurred; during the Younger Dryas and the short 8.2 kiloyear event. The African humid period ended 6,000–5,000 years ago during the Piora Oscillation cold period. While some evidence points to an end 5,500 years ago, in the Sahel, Arabia and East Africa, the end of the period appears to have taken place in several steps, such as the 4.2-kiloyear event.
Paleotempestology is the study of past tropical cyclone activity by means of geological proxies as well as historical documentary records. The term was coined by American meteorologist Kerry Emanuel.
The Garth tsunami is a likely prehistoric tsunami off the Shetland Islands that may have occurred 5,500 years ago. Its origin is unknown; impact events, earthquakes, and submarine landslides similar to the Storegga Slide 8,100 years ago have been proposed as factors contributing to the event. Evidence suggests a run-up of more than 10 metres (33 ft) in the Shetland Islands. It probably had great impact on coastal communities in the region; mass burials dating approximately to that time in the Shetland and Orkney Islands have been interpreted to host its fatalities.
Mundafan was a former lake in Saudi Arabia, within presently desert-like areas. It formed during the Pleistocene and Holocene, when orbitally mediated changes in climate increased monsoon precipitation in the peninsula, allowing runoff to form a lake with a maximum area of 300 square kilometres (120 sq mi). It was populated by fishes and surrounded by reeds and savanna, which supported human populations.
A paleotsunami is a tsunami that occurs prior to written history where there are no documented observations. Paleotsunamis are evidenced by modern technology and scientific research. One of the largest was a megatsunami resulting from the asteroid that wiped out the dinosaurs.
