recentpopularlog in

geology

« earlier   
What is Called Thinking in the Anthropocene? — The Revealer
This is a piece about failures. My failures, mostly, as a thinker and a scholar, but also the failure of my field and the failure of all of us to think what will come in the next ten, twenty, thirty, hundred years.
additivism  anthropocene  deep  time  environment  geology  human  stream 
22 hours ago by therourke
The Arrogance of the Anthropocene - The Atlantic
On geological timescales, human civilization is an event, not an epoch. Humans are now living in a new geological epoch of our own making: the Anthropocene. Or so we’re told.
additivism  anthropocene  apocalypse  deep  time  environment  evolution  extinction  geology  human  posthumanism  reading  group  stream 
4 days ago by therourke
How Geology Made America Great
s expanded westwards in search of new land. This led to a conflict between England and France above the control of the few gaps and mountain passes in the Appalachians. The English colonists were far more numerous and better supplied than the French, having direct access to the sea. The rugged, poorly accessible terrain of the Appalachians proved to be difficult for the French and allied Indians to defend, and were eventually lost to the expanding British colonies. After the end of the French-American War, the English crown wanted to limit new settlements to the area of the Appalachians, hoping to avoid further conflicts with the remaining French and Spanish forces. However, the unexpected result of this political move was resentment among the American colonies. The colonists became convinced that the crown didn't care for the political future of the successful expanding colonies. Among other factors, this resentment would contribute to the later Revolutionary War, leading in the end to the foundation of the United States of America.
Forbes  geology  history  France  uk  spain 
5 days ago by Kirk510620
Discovery of Ancient "Superdeep" Diamonds Reveals Glimpse of Early Earth
The early Earth looked a lot different than the Earth we know today, but there are still traces of that chaotic planet deep below the surface. "Superdeep" diamonds from Brazil confirm that there is an "ancient reservoir" of materials deep below that holds clues about what early Earth was like.

These superdeep diamonds may not look as resplendent as the ones we’re used to seeing in jewelry, but their value comes from a quality beyond their beauty. Because they form between 230 and 800 kilometers (about 140 to 500 miles) beneath the Earth’s surface, they can carry a lot of information about what’s going on down there. Specifically, they contain traces of two helium isotopes: helium-3 and helium-4.

These two isotopes turned out to be very important. There are only trace amounts of helium-3 on Earth, but it’s very sought after for its potential as a fuel in fission reactors. Some naturally occurring helium-3 in the mantle is thought to have accrued on our planet over time. Helium-4, on the other hand, is far more naturally abundant and is also produced by radioactive decay. That means that typically, we expect to see more helium-4 than helium-3.

But in some places, scientists have noted far more traces of helium-3 than you might expect to see based on it’s typical abundance. For instance, it’s more abundant than it should be in “ocean island basalts” — essentially plumes of lava that erupt beneath the ocean floor and eventually go on to form islands. That’s the process that formed Hawaii and Iceland.

This unexpectedly high abundance in the superdeep diamonds suggests that helium-3, which is sometimes called the “primordial isotope”, is actually locked away beneath the surface in a type of reservoir that’s helping boost its numbers.

In 2013, a paper published in Nature Geoscience noted that the helium we saw in ocean island basalts likely came from one of these reservoirs. But they speculated that there may be another “deep, still enigmatic, source that must have been isolated from processing throughout Earth history,”

Timmerman and her team believe that they’ve found traces of that “enigmatic” reservoir in these superdeep diamonds.

Specifically, she observed that some of these diamonds tended to have “a clear increase” in helium-3 and corresponding but smaller increases in helium-4. That ratio, as these authors note “supports the presence of a primordial helium-3 plume.” Therefore, this helium reservoir almost certainly does exist, and because of the depth of the diamonds themselves Timmerman explained that we now have a better sense of where it is.

science  geology 
6 days ago by rmohns
'Punch in the gut' as scientists find micro plastic in Arctic ice - Reuters
LONDON (Reuters) - Tiny pieces of plastic have been found in ice cores drilled in the Arctic by a U.S.-led team of scientists, underscoring the threat the…
newspaper  articles  pollution  environment  biodegradable  plastics  geography  geology  cryosphere  glacial  permafrost 
7 days ago by asaltydog
The Arrogance of the Anthropocene - The Atlantic
"On geological timescales, human civilization is an event, not an epoch"

"That this otherwise typical and temporary warm spell of the Pleistocene has also been strangely given its own epoch, the so-called Holocene—quite unlike the dozens of similar interglacials that came before it—is the original sin of anthropocentric geology."

Some nice discussions of how tenuous the evidence for human civilization might be tens of millions of years from now. ("... the longest-lived radioisotope from radioactive fallout, iodine-129, has a half-life of less than 16 million years. If there were a nuclear holocaust in the Triassic, among warring prosauropods, we wouldn’t know about it.") [iodine-129 decays to xenon-129, which is 26% of all xenon]
geology  science 
7 days ago by PeterErwin
Gaia rebooted: New version of idea explains how Earth evolved for life | New Scientist issue 3222 Mar 2019
"The controversial Gaia hypothesis sees Earth as a superorganism adapted to be perfect for life. A weird type of evolution may finally show how that actually happens"

"As far as we know, Earth is a one-off: there is no population of competing, reproducing planets for natural selection to choose between to form the next generation. And yet, like a superorganism honed by evolution, Earth seems to self-regulate in ways that are essential for life. Oxygen levels have remained relatively constant for hundreds of millions of years, as has the availability of key building blocks of life such as carbon, nitrogen and phosphorus. Crucially, Earth’s surface temperature has remained within the narrow range that allows liquid water to exist. It is true there have been upheavals: during a “snowball Earth” episode about 700 million years ago, for example, almost the entire surface was frozen. “But the key question is, why does it spend so much time in a stable state and not just flying all over the place?” asks Tim Lenton at the University of Exeter, UK."

Def of "selection by persistence":

"[Tim Lenton, Execter] suggests, Earth and the early life on it might have interacted haphazardly at first. Unstable configurations – those, say, with little or no cycling of key elements such as nitrogen – would have failed quickly, requiring life to reboot nearly from scratch. Eventually, though, the system must have stumbled on a stable configuration, with better cycling and tighter regulatory mechanisms. It should be no surprise, then, that the planet of today has strong regulatory systems."

"From Bouchard’s perspective, natural selection favours traits that enhance persistence, with reproductive success being one way to do that, but not the only one."
equilibrium  NewScientist  evolution  complexity  geology 
9 days ago by pierredv
Geoff Manaugh, "We Thought We Lived on Solid Ground. California’s Earthquakes Changed That"
"To no small extent, earthquakes force us to ask what we mean by “land” in the first place, including how we define architecture when the ground it stands on moves like the sea. At their best, earthquakes remind us that our myths and legends of seafaring journeys, from Odysseus to South Pacific islanders, are in a way still with us. The sea is here, too, if only we wait long enough to experience it."
GeoffManaugh  NYT  earthquakes  faultlines  geology  DeepTime 
10 days ago by briansholis
Jenny Odell: Excavating Calabazas Creek: An Inefficient Route Through Silicon Valley
Even in the midst of a slurb made of corporate franchises and walled tech gardens, it’s not possible to be nowhere, any more than it is for us to engineer away the water during a flood or stop cracks from appearing in pavement. Water moves and land moves. Nothing on earth ever stands still.
california  realestate  nature  ecology  geology  industry 
11 days ago by matthewmcvickar

Copy this bookmark:





to read