Skip to content

Posts from the ‘Climate/Weather’ Category

25
Aug

Then, Now, and Beyond

Field trip participants from the Northern Colorado Geologists group listen to Dr. Donald Boyd, Professor Emeritus of Geology from the University of Wyoming offer his thoughtful interpretations on the depositional origin of the Precambrian Nash Fork Formation stromatolites.

I had the privilege, once again, to participate in a unique field trip with fellow scientists and friends to visit a fascinating geologic site in southern Wyoming. To be sure, a geologic field trip is always about ancient time travel, but this was truly remarkable. Our excursion offered us an extremely distant target:  2 billion years in time yet only 2 hours on the highway from Fort Collins.  Our destination were the Precambrian-aged stromatolites of the Medicine Bow Mountains which in simple terms are– well– rocks that contain fossil slime. Fossil slime? Yes but really, really old fossil slime that was the dominant life form on our planet for more than half of earth’s entire existence!

Typical outcrop of the Precambrian Nash Fork Formation. Tectonic forces have tilted the original layers into an upright position while deep-seated physical and chemical processes caused silicification (hardening) of the original lime-mud layers.

Typical outcrop of the Precambrian Nash Fork Formation. Tectonic forces have tilted the original layers into an upright position while deep-seated physical and chemical processes caused silicification (hardening) of the original lime-mud layers.

Rock-bearing stromatolites of this age are uncommon and quite different than typical Precambrian rocks we find in Colorado (and in many other places). These stromatolites are essentially sedimentary in nature as they originally formed at or near the earth’s surface. Over time, they have been deeply buried and ‘squeezed’ into meta-sedimentary rocks and then uplifted -most likely during multiple mountain building events in this area. Finally, in a mere fraction of its 2 billion year old history, Ice Age glaciation (which ended about 10,000 years ago) uncovered the wonderful outcrops we visited today.

Convex laminae that follow the undulations of the ancient seafloor. A great variety of shapes and forms reflect both original growth patterns as well as sliding, slumping and collapsing of the microbial/sediment mats.

So now, we have a 2 billion-year old snapshot of Earth Antiquus where nothing more than simple lifeforms occupied the young Earth. A human visitor would be staring at bare rock everywhere amidst seas whose shallow margins supported the growth of thinly layered microbial mats. Over time- perhaps  days, weeks or months, the sticky surfaces trapped lime mud into delicate wavy strata resulting in undulating domes and troughs that are the tell-tale signs of once living stromatolites. How do we know this?

Modern stromatolites from western Australia. wikipedia.org/wiki/File:Stromatolites_in_Sharkbay.jpg

Modern stromatolites exist today in a few places that offer a glimpse into the mechanics of primitive algae and bacteria that were life’s rulers of Planet Earth for nearly 3 billion years.

So why do we get so excited about 2 billion year-old microbes? It is a window of understanding into the origin of our modern oxygen-rich atmosphere and perhaps– a view of what Extraterrestrial Life may actually look like.  After all, astronomers are routinely discovering sister earth “exoplanets” whose billions-year old histories almost certainly contain similar evolutionary story lines.  Just maybe…

Oblique cross section of stromatolite dome contrasting 2 billion year old life with modern flowers which made their first appearance about 150 million years ago.

Oblique cross section of stromatolite dome contrasting 2 billion year old life with modern flowers which made their first appearance a mere 150 million years ago.

So, we salute these extraordinarily ancient stromatolites as postcards of primitive Earth. Envision countless mats of slime yielding tiny bubbles of oxygen that in turn tempered Earth’s primordial atmosphere into one that could harbor more complex life forms. And maybe, just maybe these most ancient of fossils offer us a clue to our most likely alien encounter from the beyond.  A self guided walking tour of the site can be downloaded from the Wyoming State Geologic Survey.

Closer to home in Northern Colorado, these ancient stromatolites form siliceous (resistant) mounds as part of the Jurassic (150 my) Morrison Formation. The larger ‘heads’ are about 1 meter in diameter.

Wyo_Stromatolite 63

Valley margin outcrops feature glacially caused striations. Sand and gravel embedded in Ice Age valley glaciers gouge the underlying rocks in a geologic process that is a mere 10,000 (or a bit older) years old

Read more »

Advertisements
26
May

Storm Drama

Screen Shot 2014-05-26 at 5.25.26 PMRadar imagery reveal late May thunderstorms blooming along a southwest to northeast line southwest of Fort Collins on the afternoon of May 25.  Time lapse imagery facing south captures the drama of north and westerly flow- a bit unusual as most summer storms track east and northeast from the mountains to the plains.  Late spring in northern Colorado has brought a lot of moisture- with the threat of stream flooding now and in the days to come.  Snowpack in the mountains is still about half melted so a string of warm weather could add to river discharge here and downstream.  

29
Oct

Fall Colors from Space

UnitedStates_amo_2013294

October, 2013 satellite view of folded Appalachain Mountains in Eastern Pennsylvania

The NASA satellite AQUA captured this October image of eastern Pennsylvania and its rusty brown-colored ridgelines of the Appalachian Mountains. The NASA website also shows a comparision with the same view from the more ‘summery’ September.  Here in in the Colorado Rockies, we enjoy similar October colors at ground level- albeit with less color diversity than our Appalachian counterparts.  Aside from the season, what ties both images together are the nature of the ridges- parts of folded mountain belts of different ages. The vegetation here in the foothills of the Rockies flanks the sandstone ridges. In Eastern Pennsylvania, hues of gold, yellow and red deciduous trees cover the ridges. Now to totally confound it all, the age of the Colorado rocks are Pennsylvanian in age.

IMG_3193 - Version 2

Yellow cottonwood trees flank the red sandstones of the Fountain & Ingleside Formations in Lory State Park, Colorado

19
Sep

Front Range Floods and a Recipe for a Canyon Part 2

The video of road damage along Highway 34 from Loveland to Estes Park is amazing. The road was reinforced after a deadly flood in the summer of 1976 that killed 143 people in this canyon.  Now, almost a week after the 2013 flood, river waters are receding to reveal destruction among 17 counties- both in the mountains and on the high plains.  So far nearly 19,000 homes have been damaged, and over 1,500 have been destroyed.  The Colorado Department of Transportation estimates that at least 30 state highway bridges have been destroyed and an additional 20 are seriously damaged, with repairs for damaged bridges and roads expected to cost many millions of dollars.  Canyon cutting in the age of human settlement is expensive and deadly.

24
Jul

Debris Flow Chasers

Debris flows are a type of landslide where a liquified jumble of earth and plant materials form a fast moving mixture following a rain event, dam breach or rapid snow or glacier melting ( from a volcanic eruption, for example). Here, people anticipated the flow along a dry creek bed and essentially ‘chased’ the event down as a storm chaser would track down severe weather such as an outbreak of tornadoes. Is this safe?…not at all! but what’s so eerie is the way the flow occurs well after the rain storm. This reminds me of the way tsunami waves devastate coastal areas, many hours after large submarine earthquakes generate their initial jolt.

20
Jun

Solstice Joy

20130620-232101.jpg

Setting sun glows from the south

20130620-232115.jpg

Setting sun glows from the north

It may not be apparent to many that the first of day of summer (and winter) are truly astronomical events of the highest magnitude. It is the longest (or shortest) day of the year and where the sun’s rays are at their highest angle in the Northern Hemisphere. For many cultures the summer (and corresponding) winter solstice mark either the a start of season or mid-season celebration One interesting observance is from the Atacama cultures in northern Chile where they celebrate the occasion with a ‘take the Sun back’ festival. The cultural reference, in scientific terms, is the apparent reversal of the Sun’s march north and its regression to the South after the Solstice. All of these movements, of course, are a consequence of the earth’s upper (northern) hemisphere tilted toward the sun on June 21– away from the Sun on December 21.
In this way, facing due west at the same spot on my street 6 months later, you can see the sun’s light emanating from its northernmost position (Summer) and its southernmost position (Winter).

22
May

Tornado Country

PBS’s NOVA reports on tornadoes in the wake of the recent deadly storms that devastated Moore Oklahoma and surrounding areas. Why are almost three fourths of the world’s tornadoes located in the US? The unique climatologic and geographic conditions found in the North American midwest account for a great deal of it. The other reason, they offer, is many countries mis-report or don’t report these storms as tornadoes at all. Check it out.
http://www.pbs.org/wgbh/nova/earth/tornado-country.html

20130522-213430.jpg

29
Apr

Florida Clouds

Everyday sky scenes come alive when time is compressed using time lapse imagery. Clearly visible are the low cumulus clouds racing westward during a typical Florida day while you can see upper level clouds moving in almost an opposite direction to the northeast. Filmed at Jessica’s mom’s home in south Florida on April 27, 2013. A bonus are the brief but beautiful pink and orange tinged clouds that end the day. View to the south over the Deerfield Country Club.

10
Mar

March Snow Leaves Quickly

A fast moving snowstorm comes & goes quickly. The following day brings warm temperatures & strong winds to dissipate the snow from my front lawn.

1
Nov

From Donna to Sandy- A Precautionary Tale

Superstorm Sandy leaves a foot of wet sand at 141 St in Belle Harbor. Photo courtesy of Peter Thomas Senese, 2012

Fifty two years and 7 weeks later, my hometown of Rockaway Beach is ravaged by the ‘storm of the century’. Technically that would be this century. The hurricane-turned superstorm “Sandy” struck this part of coastal New York as did Hurricane Donna a half century ago on September 12, 1960. But this 21st century storm was far more powerful. This was due to the aggregation of massive storm systems coupled with a high tide that doomed the barrier islands along the mid-Atlantic coast.

Hurricane Donna’s floodwaters lap onto the front steps of my childhood home

Is this the realization of global warming? Is this truly emblematic of the intensity of weather events now being predicted? Between the scientific analyses and the political maneuvers to affirm or deny what we are or aren’t doing to affect climate change, one thing is clear to me. Nature, eventually will win over our attempts to control it and we must accommodate this fact of life. Is this a 50 year storm or a 100 year storm? Left to human memory, we are woefully disadvantaged to see the real time scale that affects climate in hundreds or thousands of years.

Brother Sandy (no relation to the 2012 storm) wades through the flood waters brought on by Hurrican Donna on September 12, 1960.

Instead of the, “is it climate change, or not argument” I like to invoke the precautionary principle which subscribes to the idea that it makes sense to mitigate our impact on our earth’s atmosphere despite the “truth” of global climate change. So, given we are warming from an Ice Age, if sea level rises less quickly (and it will) and if global temperatures rise more slowly (and they will) than predicted, why not take steps anyway to invest in better seawalls, levees, and smarter zoning along areas where we are most vulnerable. When we buy insurance for our home, vehicle, and our family, aren’t we also also subscribing to the adage “better be safe than sorry”? Floods, fires and quakes are natural processes on our planet, so why not improve our relationship with nature by reducing our carbon footprint, and moving toward more sustainable forms of energy use. Although I may live 2,000 miles away from my childhood home, the recent images of destruction and loss remind me how connected we all are.