First noticed by westerners in 1965, when
the Gemini-4 spacecraft flew over northwest Africa (
alternate source, with link to uncompressed TIF |
in Earth photographs from Gemini III, IV, and V on Archive.org), the
Richat Structure in
the Sahara desert of west–central Mauritania resembles an impact crater or a circular target (or
a possible Atlantis, or
Plato's circular city, or maybe
an open-pit mine), but is
a naturally occurring 40-50 km (25-30 mi) geologic dome that has eroded over time. It's large enough that,
when seen in person, the
scale of the geography is hard to capture. But it is
quite impressive when
seen from space (mentioned
previously)
posted by filthy light thief
on Feb 12, 2013 -
7 comments
The Timeline of the Far Future is a Wikipedia article which serves as a gateway to a ton of fascinating scientific topics on the far edge of human understanding: ~50,000 years from now the Earth will enter a new
Glacial period; ~100,000 years from now the Earth will likely have experienced a
supervolcanic eruption; ~10,000,000 years from now the
East African Rift divides the continent of Africa in to two land masses; ~20,000,000,000 years from now the Universe effectively dies due to
The Big Rip.
posted by codacorolla
on Jan 22, 2013 -
93 comments
Ron Blakey makes
paleogeographic maps of the ancient world.
The paleogeographic maps show the varied landscapes of the ancient Earth through hundreds of millions of years of geologic time, including distribution of ancient shallow seas, deep ocean basins, mountain ranges, coastal plains, and continental interiors. Tectonic features shown include subduction zones, island arcs, mid-ocean ridges and accreting terranes.
posted by zamboni
on Dec 5, 2012 -
14 comments
Understand something of the earth beneath your feet and the landscape in front of you. These sites provide a chance to see geologic sites and also see expert interpretations.
Geology of Southern England's
Jurassic Coast - many pages with detailed strata and sometimes questions to
challenge yourself (click photos to enlarge), by Ian West of Southampton University.
[more inside]
posted by Listener
on Mar 2, 2012 -
6 comments
Libyan Desert Glass is strewn over an area of hundreds of square kilometers in the Great Sand Sea, a region desolate even by the high standards of the Sahara. As
one account of a recent trip to acquire Libyan Desert Glass puts it: "Out there, death sits on your shoulder like a vulture." While some would have you believe that Libyan Desert Glass is
evidence of ancient atomic warfare, it is probably evidence of a
massive meteorite or comet explosion nearly thirty million years ago, similar to Tunguska, but much bigger. The stone age Aterian peoples made
tools from it, but the remoteness and inhospitality of the Great Sand Sea has ensured that until recent times it has mostly been undisturbed. However, a
breast ornament buried in Tutankhamen's tomb has a scarab made from Libyan Desert Glass, the only piece made of the material to have been found by Egyptologists, and
how Tutankhamen's jewelers acquired it has remained a mystery. Until
now.
[Previously]
posted by Kattullus
on Dec 8, 2011 -
38 comments
The Mississippi River has the third largest drainage basin in the world, exceeded in size only by the watersheds of the Amazon and Congo Rivers. It drains 41 percent of the 48 contiguous states of the United States.
The basin covers more than 1,245,000 square miles, includes all or parts of 31 states and two Canadian provinces. The US Government has tried to improve navigability of the Mississippi River and its major tributaries for more than a hundred years, focused in part by
Mississippi River Commission, created in 1879. The river is ever-changing, and in an attempt to understand their domain, and
in 1941, MCR hired Harold Norman Fisk to conduct a geological investigation of the Lower Mississippi Valley. The result was
a colorful map that displayed the historical course of the riverway from southern Illinois to southern Louisana. His vivid maps are
available online in full, but beware:
the files are very large.
posted by filthy light thief
on Sep 30, 2011 -
24 comments
SEED Magazine:
Wealth of Nations:
"Shared natural resources underpin the global economy, but our current economic system does not acknowledge their worth. Can a major new effort to assess the costs of biodiversity loss force a paradigm shift in what we value?" [more inside]
posted by zarq
on Nov 30, 2010 -
10 comments
Experts are little help in the constant struggle in this conversation to separate myth from reality, because they have the same difficulty, and routinely demonstrate it by talking past each other. Respected scientists warn of imminent energy shortages as geologic fuel supplies run out. Wall Street executives dismiss their predictions as myths and call for more drilling. Environmentalists describe the destruction to the earth from burning coal, oil, and natural gas. Economists ignore them and describe the danger to the earth of failing to burn coal, oil, and natural gas. Geology researchers report fresh findings about what the earth was like millions of years ago. Creationist researchers report fresh findings that the earth didn’t exist millions of years ago. The only way not to get lost in this awful swamp is to review the basics and decide for yourself what you believe and what you don’t.
[more inside]
posted by infinite intimation
on Jun 27, 2010 -
31 comments
The Polar Discovery team has documented science in action from pole to pole during the historic 2007-2009 International Polar Year, and
covered five scientific expeditions. The science projects explored a range of topics from climate change and glaciers, to Earth’s geology, biology, ocean chemistry, circulation, and technology at the icy ends of the earth. Through
photo essays and
other multimedia, they explain how scientists collected data and what they discovered about the rapidly changing polar regions. From the awesome folks at
WHOI.
posted by netbros
on Nov 9, 2009 -
4 comments
Waterlines is a new online exhibit from the excellent
Burke Museum at the University of Washington, Seattle. It tells the story of the land underlying Seattle, one of the United States' most geologically active city sites, and of the human attempts to engineer this landform. Closely related are the
archaeology of West Point and
Coast Salish Villages of Puget Sound (e.g., read the
story of North Wind and Storm Wind).
posted by Rumple
on May 2, 2009 -
3 comments
An erupting stratovolcano poses numerous hazards for nearby habitation, but none nearly so terrifying and deadly as the
pyroclastic flow.
Pyroclastic flows, comprised of tons of superheated sulfuric gases, particulate rock materials and ash, can reach temperatures of 1,830 °F and travel at alarming speeds up to 450mph. Convection of materials within the clouds causes them to become a suspension,
fluidizing and
thundering noxiously across the surrounding landscape for miles, in some cases even uphill or across open water. Wherever these clouds come in contact with humans the result is catastrophe, as the residents of
Herculaneum and
St. Pierre, Martinique learned within minutes of the eruptions of Vesuvius in 79AD and Pelee in 1902-- both towns were overwhelmed by pyroclastic clouds, igniting all flammable materials and incinerating and suffocating the inhabitants. None survived
Herculaneum, while just two of
St. Pierre's 26,000 survived, one of whom was a prisoner condemned to death and awaiting his execution in a dungeon cell. Despite their incredible capacity for violence, pyroclastic flows are also capable of producing
mesmerizing,
awe-inspiring beauty.
posted by baphomet
on Feb 18, 2009 -
18 comments
