GeoHammers

The GeoHammers are cataclysms that affect earth at various times. These are real world events, documented throughout the geological record. CE means 'Common Era', usually a substitute for AD; BCE means 'Before Common Era', usually a substitute for BC. The GeoHammers are listed in reverse chronological order; most recent events first, most ancient events last. Several non-GeoHammer events (such as the flooding of the Black Sea) are included for modern/historical comparisons of major events in human history. These non-GeoHammer events also help allow for global correlations in events; what seems to be a local disaster may be part of a larger, global catastrophe. References are given where available.

This page was originally designed to look for astronomical 'hammers' that impacted life on earth, but may soon be renamed to 'biohammers' that have altered and shaped life on earth in dramatic ways. The hammer concept comes from Larry Niven and Jerry Pournelle's book Lucifer's Hammer, published in 1977.
http://en.wikipedia.org/wiki/Lucifer's_Hammer

The VEI, or Volcanic Explosivity Index, runs along a scale of 1-8, with a 5 being an ejecta volume of greater than one kilometer cubed.
http://en.wikipedia.org/wiki/Volcanic_Explosivity_Index

An asteroid or a comet is believed to have detonated well above the earth's surface in Siberia; the event went off with the power of several nuclear weapons, splaying out trees and laying them down for a considerable area. Because the region was never really mapped before-hand, and was so isolated, remote, and unpopulated, the event wasn't even discovered until the 1920s. Lake Cheko is believed to be the impact basin that has long eluded researchers.

Sadie MacMillan. February, 2008. “Long-lost Siberian crater found?” Geotimes, Vol 53, No 2, page 9.

Mount Tambora in Indonesia blows, causing the 'year without a summer'. Recent evidence suggests that a previously unknown volcano with perhaps half the eruptive power of Tambora, blew in 1809; the 1809 and 1815 eruptions together caused the coolest decade on record in the last 500 years.

http://en.wikipedia.org/wiki/Mount_Tambora
http://www.physorg.com/news176049231.html

The Lisbon Earthquake kills anywhere from 60,000 to 100,000 people, and is estimated to be a Magnitude 9 disaster. The event inspires theodicity, a philosophical belief that attempts to reconcile a benevolent God with Evil in the world.

http://en.wikipedia.org/wiki/Lisbon_earthquake

The 'Great Drought' of 1250-1299 was severe enough to force the Pueble Indians of Chaco Canyon, Arizona, to disperse from their localized areas.

(Brian M Fagan. 2006. “Archaeology: A Brief History”, 9th ed. p241-242. Pearson / Prentice Hall, NJ.)

Baekdu-san, Korean for 'white-headed mountain', lies on the border between North Korea and China. It's eruption was detailed in histories as far away as Japan.

http://en.wikipedia.org/wiki/Baekdu_Mountain

The Moche of the Andes suffered a small drought from 534-540, but suffered a 30-year drought from 563-594 – collapsing their civilization, which relied on mountain run-off to irrigate the crops.

Brian M Fagan. 2006. “Archaeology: A Brief History”, 9th ed. p238-239. Pearson / Prentice Hall, NJ.

An equatorial volcano blows, causing a global chill, and plenty of war. The exact location of the volcano is unknown, though believed to be in the tropics; it's existence is known of through ice core samples in Greenland. Evidence suggest it was a larger even than Mount Tambora. The timing of the event leads some to believe it may have had a powerful influence on the Dark Ages after the fall of the Roman Empire.

Larsen et al, Geophysical Research Letters, 29FEB2008
National Geographic News, 19MAR2008.

The Hatepe (or Taupo) eruption in New Zealand rates a VEI 7, turning the sky red over both Rome and China.

http://en.wikipedia.org/wiki/Hatepe_eruption

Minoan eruption of Thera releases 24 cubic miles of debris and destroys the nearly circular caldera already present. Some speculate that this could have been the seed for the stories of Atlantis. Others speculate that this eruption triggered the plagues of Egypt as mentioned in the Bible. Exact dating remains questioned, and the VEI is estimated at 77.

http://en.wikipedia.org/wiki/Minoan_eruption

Mount Aniakchak is an Aleutian volcano in Alaska, which underwent a VEI 6 around the same time as the Minoan eruption, confusing ice cores trying to date the Greek island eruption. The current caldera last erupted in 1931.

http://en.wikipedia.org/wiki/Mount_Aniakchak

Evidence of a global drought has been found in glacial data world wide from this time frame (plus or minus a century or so). Small dust particles, roughly one micron in diameter, are seen in ice cores.

PhysOrg, 19JUN2009, http://www.physorg.com/news164546585.html

Glaciers in Peru rapidly advanced, covering a tropical marsh and preserving it's plants. Other indicators point to this being a temporary global cooling event.

PhysOrg, 19JUN2009, http://www.physorg.com/news164546585.html

The Kikai Caldera of Japan put out 36 cubic miles of material. Radiocarbon dating puts it at 4500 BCE instead of 5300 BCE indicated by archaeological evidence.

http://en.wikipedia.org/wiki/Akahoya_eruption

The Euxine Lake (now known as the Black Sea) is flooded by the rising waters of the Mediterranean, rising 500 feet and transforming the region from a nexus of agriculture and civilization into a salty shore. This is possibly the 'great flood' of Hebrew and Sumerian history.

Brian M Fagan. 2006. “Archaeology: A Brief History”, 9th ed. p235-236. Pearson / Prentice Hall, NJ.

Crater Lake, icon of Oregon, was formed when Mount Mazama collapsed in this VEI 7 eruption. The volcano was estimated to be a 14,000 foot peak before it fell, with part of its remaining caldera forming an 8,000 foot peak today.

http://en.wikipedia.org/wiki/Mount_Mazama

Kurile Lake in the Kamchatka range of Russia is the remains of a VEI 7 caldera.

http://en.wikipedia.org/wiki/Kurile_Lake

The Younger Dryas event was a period of extreme cooling theoretically caused by an abrupt change in the North Atlantic thermohaline current, brought about by Lake Agassiz flooding down the Hudson; this event was possibly brought about by a cometary impact. Recent evidence indicates the cooling occurred within the span of mere months as the thermohaline current shut down. The time period also coincides with 1500y solar cycles, which have been implicated in repeating cooling events. Other evidence points towards this being the start of the Anthropocene, due to men wiping out the huge methane producers of the age.

http://en.wikipedia.org/wiki/Younger_Dryas
http://www.physorg.com/news99134637.html
http://en.wikipedia.org/wiki/8.2_kiloyear_event
http://www.physorg.com/news178804829.html
http://www.physorg.com/news193847219.html

This Japanese caldera on the island of Kyushu is home to Kagoshima and a post-caldera volcano. The original volcano was estimated at VEI 7.

http://en.wikipedia.org/wiki/Aira_Caldera

New Zealand's north island volcano of Taupo detonates, leaving behind a lake twenty miles across in the midst of the island. The VEI 8 explosion a hundred cubic miles of pyroclastic flows alone.

http://en.wikipedia.org/wiki/Oruanui_eruption

The Phlegraean Fields of Naples still has hydrothermal activity from the VEI 7 eruption.

http://en.wikipedia.org/wiki/Campi_Flegrei

Modern genetic forensics indicates that humans have a relatively small amount of biodiversity, most probably due to a bottlenecking event some 70-80 thousand years ago. The information indicates that all modern humans descended from between 2,000 and 20,000 people in Africa during that time frame. The timing of this bottlenecking event seems to coincided with the eruption of one of the world's largest known super volcanoes that now forms Lake Toba in Indonesia. The eruption of the Toba caldera plunged the world into an 'instant ice age' akin to a nuclear winter, apparently wiping out all other humans across the world. After this bottleneck, humanity apparently exploded out of Africa, reaching almost all of Eurasia not covered by ice within a few thousand years.

http://en.wikipedia.org/wiki/Population_bottleneck
http://en.wikipedia.org/wiki/Lake_Toba
http://www.physorg.com/news178210720.html
http://www.physorg.com/news103983229.html

VEI 8 listed on the main Wikipedia Volcanic Explosivity Index page.

SJA Brown, CJN Wilson, JW Cole, J Wooden. 1998. “The Whakamaru group ignimbrites, Taupo Volcanic Zone, new Zealand: evidence for reverse tapping of a zone silicic magmatic system.” Journal of Volcanology and Geothermal Research. 84(1-2): pp1-37.

Yellowstone hot spot releases 240 cubic miles of ash and debris – 280 times more than the 1980 Mount St Helens eruption. An eruption 2.1M BCE ejected 600 cubic miles of ash and debris, while another eruption 1.3M BCE ejected 67 cubic miles. The 'line of fire' Achenback writes about begins roughly 20M years ago in southern Oregon and northern Nevada, with periodic supervolcano eruptions. The McDermitt volcanic field erupted between 16.5 and 18 million years ago, followed by the Owyhee-Humboldt at 13.8M, Breneau-Jarbidge at 12.5M, Twin Falls at 10.8M, Picabo at 10.3M, and Heise at 6.65M years ago, with the majority of these moving through southern Idaho.

Achenbach, Joel. August 2009. National Geographic, p67.

Genome research with the Alu gene indicates human ancestors were an endangered species roughly 1.2 million years ago, with a breeding pool of as little as 18,500 individuals. Worse, the condition might have persisted for nearly a million years, indicating how fragile our early development as a species may have been.

http://www.physorg.com/news183278038.html

Located in the Argentinian Andes, Cerro Galan is a VEI 8 that has gone from large lake to salty lagoon due to a resurgence of the eastern caldera floor.

http://en.wikipedia.org/wiki/Gal%C3%A1n

Ice sheets develop on Greenland, supposedly due to dropping levels of CO2. The Ice Ages in general are believed to have begun around this time.

http://en.wikipedia.org/wiki/Quaternary_glaciation

Geologists argue over whether La Garita Caldera or the Siberian Traps were the largest explosive eruption in all of history. Located in US Rockies, the VEI 8 caldera is situated near La Garita, Colorado. The output of 5,000 cubic kilometers was an estimated equivalent yield of 5,000,000 megatons of TNT.

http://en.wikipedia.org/wiki/La_Garita_Caldera

South American and Australia break away from Antarctica, allowing the creation of the Antarctic Circumpolar Current. This dramatically lowers the temperature of Antarctica, allowing the creation of the permanent ice sheets oer the Gamburtsev Mountains. This time frame also corresponds to a massive drop in atmospheric CO2 levels.

Morton, Mary Caperton. September 2009. “How Antarctica Got Its Ice”. Earth. p9

A series of collisions with large meteors creates craters in Chesapeake Bay, Siberia's Popigai Crater, and the Timor Sea, as well as a sheet of molten rock falling across much of eastern North America (such as Tom's Canyon impact crater). This, rather than the opening of the Drake Passage, may have started the real changes leading to the end of the Eocene and the beginning of the Oligocene.

http://en.wikipedia.org/wiki/Chesapeake_Bay_impact_crater
http://en.wikipedia.org/wiki/Popigai_crater
http://en.wikipedia.org/wiki/Toms_Canyon_impact_crater
http://www.physorg.com/news193556580.html

Azolla event, in which an isolated arctic sea formed a fresh-water top-layer that supported an Azolla sp of fern that sequestered as much as 80% of the world's CO2 in the anoxic bottom layer. An alternative explanation to the CO2 levels dropping is the reaction of CO2 with the earth itself, especially with newly formed volcanic rock, such as would have formed during the Deccan Flats outbreak in Indian.

http://en.wikipedia.org/wiki/Azolla_event
Sid Perkins, 11OCT2008, “Continental clash cooled climate; When India and Asia collide, sources of CO2 disappeared”, Science News VOL 174 NO8 p12.

Earth's CO2 levels shot up to 1700PPM, and the Arctic Ocean was no colder than a luke-warm bath at around 73F; earth's overall temperature rose between 5 and 9 degrees Centigrade in just a few thousand years. The current assumption is that the CO2 levels were introduced both volcanically, and through the release of methane from the sea floor as methylated hydrates melted.

http://www.physorg.com/news166715232.html

Himalayan orogeny begins; Deccan Flats form, altering global atmospheric conditions as they sop up oxygen; Yucatan impact occurs. Recent evidence suggests that toxic algae may have been responsible for the deaths of the dinosaurs. As well, a massive crater west of the Deccan Flats at roughly the same timeframe as the Yucatan impact, may mean that multiple bolides struck the earth at the KT boundary. The equivalent yield has been estimated at some 250,000,000 megatons of TNT (see La Garita Caldera Wikipedia entry). Dr Gerta Keller published one of the most detailed analyses of the time, indicating multiple impacts scattered over hundreds of thousands of years – and also indicating that the impacts were not the source of the extinctions, at least individually.

http://www.physorg.com/news174827113.html - Indian Hammer
http://www.physorg.com/news175179438.html - Killer Algae
http://en.wikipedia.org/wiki/K-t_boundary
http://www.physorg.com/news202449869.html - Boltysh Crater
http://www.physorg.com/news160655449.html - Gerta Keller Analysis Reference

Mass underwater vulcanism causes near global anoxic ocean conditions, wiping out much of life in the seas and creating the shale / petroleum deposits we access today for oil. This roughly corresponds to the beginning of the Turonian Stage.

http://en.wikipedia.org/wiki/Turonian

Seventy-six percent of all species go extinct, as Pangaea breaks up with accompanying changes in vulcanism, sea-level change, and altered climate. Asteroid or comet impacts have also been implicated in the mass extinctions. This event allowed for the rise of the dinosaurs.

Permian-Triassic extinction event, cause unknown; greatest mass extinction of life ever recorded: 96% of all marine sp, and 70% of all terrestrial sp go extinct. Suspected causes of the mass extinction include the formation of the Siberian Traps, a string of volcanoes that erupted for 5 million years. One theory holds that any super-continent that forms stops subduction events along plate margins until a massive pressure release occurs. This marks the end of the trilobites and the rise of the bivalves.

http://en.wikipedia.org/wiki/Permian-Triassic_extinction_event

In one case, the Siberian Traps' formation seems to allude to modern cancer rates in one region of China, where the P-T coal of the region was altered by the long-term vulcanism 250M years ago.

http://www.physorg.com/news182600452.html

Over 70% of all species go extinct as ocean oxygen levels plummet, as global cooling causes massive ice sheets to form. Suspected causes include vulcanism and asteroid or comet impacts. The big armored fish commonly seen in museums finally died out during this event, and paved the way for the ancestral vertebrate fish to move onto land. The event can be broken up into two separate extinctions over some 15M years: the Kellwasser and the Hangenberg Events.

http://en.wikipedia.org/wiki/Late_Devonian_extinction
http://www.sciencedaily.com/releases/2010/05/100517152518.htm

Located in the Scottish Highlands, this VEI 8 last erupted in the Silurian, and has long since been ground down by glaciers.

http://en.wikipedia.org/wiki/Glen_Coe

Located in England, this VEI 8 eruption took place at the end of the Ordovician, when some 85% of all life on earth went extinct with a rapid advance and retreat of glaciers. How much Scafell affected the glacial advance and retreat is currently unknown, as Gondwana was also drifting over the South Pole at that time, forming ice caps and sequestering global water.

http://en.wikipedia.org/wiki/Scafells
Birkett, B. 2007. Scafell, Portrait of a Mountain London: Frances Lincoln Limited. p12
http://en.wikipedia.org/wiki/Ordovician

Snowball earth very nearly became permanent – and many multicellular animals died out in the near global glaciation. In addition to suspected global extinctions, the glaciation most likely scoured much of the world clean of prior fossils. The earliest known multicellular fossils, believed to be sponge-like, date from this time frame.

http://www.sciencedaily.com/releases/2010/08/100817144641.htm
http://en.wikipedia.org/wiki/Marinoan

The first of the major known glaciations in the Cryogenian Period, the Sturtian Glaciation lasted over 30M years.

http://en.wikipedia.org/wiki/Cryogenian

Oxygen is a highly corrosive gas that the first forms of life on earth found very poisonous – and yet we need it to survive. It's formation may not have been as rapid as geologists once thought, but it is still a significant event in earth's history, when the atmosphere reached oxygen percentages much like that of today's.

http://www.physorg.com/news176044643.html