The Earth Story

Classic map The Yellowstone area was declared America’s first National Park in 1872. For decades, no one really knew what a national park meant other than it was something of an interesting area – the U.S. Army even occupied the territory for years to provide some amount of protection for its resources against outsiders who wanted to make money off of the park’s features. Even though no one really knew what a national park was, within 6 years of the park being declared, geologists had a basic idea of what was going on there, as shown by this 1878 vintage geologic map.

Flinders Ranges Map This area in southeastern Australia is particularly important for geologic history. The Flinders Ranges are the result of a sedimentary basin that began forming and filling 800 million years ago prior to being built into mountains starting 500 million years ago, creating the complex folding and uplifts that are now exposed at the surface.

A tour of the Geology of the Isle of Man, in the straits between Ireland and Great Britain.

The world’s oldest geologic map

This image shows a reproduction of a 9,000 year old mural in Catalhoyuk, a Neolithic-aged settlement in central Turkey (the original mural is pictured at the link below). In the 1960’s, an archaeologist suggested that the 2 peaks, one of which was smoking, strongly resembled volcanic complex about 130 kilometers away.

He assumed that the houses here might represent an actual settlement and basically called this drawing the world’s oldest map (as it contains geology, it conveniently would be the world’s oldest geologic map as well).

Since then, other scientists have argued that the mural could instead be a painting of a leopard skin or an abstract drawing similar to others found in that site.

If the image was showing the volcano erupting…UCLA scientist Axel Schmitt reasoned that it made sense to check deposits of the volcano and ask “did the thing actually erupt 9,000 years ago?”

They collected pumice samples from the slopes and sides of the mountain, dated them in the isotope labs at UCLA, and found in fact, this volcano did have an explosive eruption right around 9,000 years ago, within error of the time the mural was made. Doesn’t prove that the mural shows an erupting volcano of course…but it at least makes it plausible that this mural was made as a consequence of that explosive eruption.

-JBB

Image credit: Sarah Murray (Reproduced with permission): http://www.flickr.com/photos/sarah_c_murray/4884064226/

Details: http://www.npr.org/2014/01/09/260918293/there-she-blew-volcanic-evidence-of-the-worlds-first-map

Geologic Map of Alaska

A geologic map is a geologist’s tool to tell what kind of rocks you will find where. To make a geologic map, you group sequences of rocks together that are related – either formed at the same time or in similar setting. These groups would be called geologic units. To put that into a map, you then need to send people out over a wide area and follow those units. The basic data presented on a geologic map is; when you are standing somewhere and you look down, what units are you standing on?

Once a map is made, it becomes a tool. Maps can be used to illustrate geologic hazards such as faults and areas at risk of landslide. They can illustrate how to follow units of economic value from one area to another. They also can be used to tell the geologic story of an area.

This geologic map of Alaska was produced by the US Geological Survey. At the link below you can zoom in and find specific unit names and descriptions. Alaska as it exists today was assembled by accreting island arcs to the continent. Today, these island arcs can be found running mostly east-west across the state, parallel to the modern day subduction zone in the Gulf of Alaska. Those island arcs are built up into mountain ranges and bounded by active faults. The pale beige units are recent sediments, deposited by rivers in the lowlands between these mountain ranges.

-JBB

Image credit: USGS http://bit.ly/2zbvwkz

Farthest Geologic Map

The Kuiper Belt Object Pluto was visited and photographed last year by the New Horizons Spacecraft as it flew by the icy world. When geologists get pictures of a new solid object, they immediately start grouping features together based on similar compositions, textures, or behaviors, and then they draw lines between them.

Until New Horizons flies by another Kuiper Belt Object in a few years, this area is the farthest spot from Earth with a Geologic Map.

This frame covers the left half of the “Heart” feature on Pluto, informally named Tombaugh Regio.

The spacecraft captured multi-spectral information across this region, so scientists will be able to analyze some of the compositions in this area. However, at present, most of the boundaries are defined based on textural terms, among them including “Rubbly”, “Cratered”, “Ridged”, “Plateau”, “Plains”, and “Uplands.”

-JBB

Image credit: NASA/JHUAPL https://www.nasa.gov/feature/putting-pluto-s-geology-on-the-map

Neat History #TBT

The Yellowstone area was declared America’s first National Park in 1872. For decades, no one really knew what a national park meant other than it was something of an interesting area – the U.S. Army even occupied the territory for years to provide some amount of protection for its resources against outsiders who wanted to make money off of the park’s features.

Even though no one really knew what a national park was, within 6 years of the park being declared, geologists had a basic idea of what was going on there, as shown by this 1878 vintage geologic map. The largest unit on the map is labeled as “rhyolite”. The mappers didn’t know the age of the rhyolite so it isn’t included in the stratigraphic column, but they recognized that most of the park was filled with igneous units of rhyolitic composition. Today we break those units apart based on their ages and eruption characteristics, but for a preliminary survey that isn’t’ bad at all. The darker red splotches are labeled as “basalt”, so the mappers already did recognize there were distinct rock types erupting within the park. Many of the features we’re familiar with in the park today, such as the Grand Canyon of the Yellowstone and the geyser basins, even have the same names as they do today.

The Park is surrounded by mountain ranges filled with Mesozoic-aged sedimentary rocks; those mountain ranges appear on the north, south, and east sides of the map and are marked with their ages (Jurassic, Cretaceous, etc.) with decent accuracy.

Within a few years of the Park’s founding, it was clear to geological surveyors that it was a large area of igneous rocks that had blasted through surrounding sedimentary rocks and mountain ranges. Found that really neat.

-JBB

Image credit: US Library of Congress https://wikimediafoundation.org/wiki/File:1878GeologicMapofYellowstone.jpg

IT’S PRETTY, BUT WHAT IS IT?

Is this modern art? Is it the drop cloth used the last time you painted your kid’s bedroom? It is the drip pan at the bottom of the refrigerator? Moldy pizza?

This is one of many geologic maps of – the moon! Though so far off, it is in some ways easier to make an accurate geologic map of the moon than of most places on the earth. For one reason, lacking plant growth, ALL the rocks of the moon are exposed and observable. With the exception of several desolate deserts, the terrestrial landscape (that is, the parts not totally hidden beneath ice or water) are rarely more than ~20% - 60% exposed. Much of what a geologist does is to guess what lies beneath the forest, grass, and soils of the healthy earth. Also, lacking much in the way of active faults and having no tectonic plates to make things difficult, the geology of the moon is far more basic.

It is a geologic world of booming impacts. This map denotes rock masses and craters of similar age and material using similar colors. It’s not (theoretically) a terribly hard thing to do: look at a good detailed photo of the moon, and try to relatively date the craters simply by observing which ones imprint others. Craters that are heavily imprinted are old relative to those less scarred, and the youngest are those that appear to lack that are not imprinted by younger craters. The evidence brought back by lunar samples indicates that the age of most of the moon’s surface features date to a period of high impact shortly after its creation.

On earth, erosion and geologic processes rapidly wipe out evidence of all but the largest of craters. In fact, the earth is as heavily bombarded as the moon. Most of the craters on this lunar map date from the period of late heavy bombardment, some 4 billion year ago. Lacking the weather and active geology of earth, the moon retains the scars of every single impact it has ever suffered.

Were it not for our often troublesome climate, frequent ice ages, and the recycling of terrestrial earth via plate tectonic processes, the geologic map of our world, also, would look more like a painting by Jackson Pollock than the soft colors of an impressionist world as by Monet.

Annie R.

Geologic Maps of the Moon (and geologic information about them by the Astrogeology Research Program!) available from: http://astrogeology.usgs.gov/maps

And several lunar, Martian, and even Jupiterian geologic maps available at: http://www.dailymail.co.uk/sciencetech/article-2130497/Its-just-blue-moon--Geological-maps-turn-planets-solar-madcap-modern-art-masterpieces.html

A NEW MAP FOR AN “OLD” PARK: Petrified Forest National Park

When I saw that a new geologic map had been made for the Petrified Forest National Park, my thoughts went back to my first visit there when I was just four-years-old; of all my childhood memories, these are among the most vibrant. It wasn’t until I could read that I could go through the “report” on the park published before I was born (I still have it); and not until I was in second grade that my piece of petrified wood from the souvenir shop was glued to a board and included as part of my first science project.

Petrified wood is rare; petrified wood of the quality in the National Park is very very rare. The existence of petrified wood in the area that would be the park was recognized in 1851, and documented in an early scientific study in 1853. First proposed to become a National Park in 1890, even with the help and study of John Muir, the area was initially declared a National Monument by Teddy Roosevelt in 1906, and finally gained National Park status in 1962.

So why is this an “old” park?

The majority of the park’s terrain consists of the upper Triassic Chinle Formation (~215 million years in age), which comprises geologic deposits from a lowland terrestrial environment with meandering river valleys, swamps and lakes. And forests. And dinosaurs. It is not unusual to encounter a Triassic formation, but so great an expanse of preserved surface lands is exceedingly rare. The Chinle is so little deformed, so mildly metamorphosed, that it is like, well, visiting the planet Earth in the Triassic. This is one of the world’s oldest and best preserved “fossil” ecosystems.

Petrified wood as in the Park is the remnant of trees and other vegetation that have been “fossilized” by replacement of plant material slowly via the penetration of silica-bearing waters which then slowly turn the wood into jasper. This jasper, in itself stunningly colored, frequently retains the original structure and appearance of the parent tree: within the park, you can visit conifer stumps with their roots intact; count the tree rings to see how old a tree was when it died in the Triassic; and even observe the borings of Triassic insects into the trees. In some petrified wood, the jasper has crystallized to from quartz crystals including semi-precious stones of citrine and amethyst.

In addition to the ancient geologic setting, the park has abundant petroglyphs, carvings on stone surfaces by native Americans, some dating back to 13,000 years in age. Much of the area referred to as “The Painted Desert” is contained in the National Park, in itself a desert region deserving its own post here on TES.

Thank you for allowing me, through The Earth Story, to revisit a place that holds a special place in my memory. Perhaps if you take your four-year-old to visit the Park, he/she too may become a geoscientist!

Annie R

Photo: Courtesy National Parks Service http://3dparks.wr.usgs.gov/pefo/html2/pf1529.htm The new map and report by the park geologists can be downloaded here: http://repository.azgs.az.gov/uri_gin/azgs/dlio/1487 I highly recommend the photo gallery of the National Park Service and USGS: http://www.nps.gov/pefo/index.htm http://3dparks.wr.usgs.gov/pefo/index.html Link to my first rock-baby: http://3.bp.blogspot.com/-PKjt9f2LER4/Ton0QhHZgxI/AAAAAAAABDs/jDdurildeEs/s1600/2%2BPet%2Bwood.jpg

Rediscovering the map that changed the world

“The map that changed the world” doesn’t need much of an introduction — we have written about William Smith’s groundbreaking map twice before (http://on.fb.me/1C7HZPB & http://on.fb.me/1bPAaco) and was the world’s first geologic map to be copied for wider use in the geologic community. A map of the British Isles’ geologic units, only 70 copies of Smith’s map were estimated to have survived out of about 370 that were originally produced.

As irony would have it, a first edition copy of the map reemerged in the archives of the Geological Society of London, more than 40 years after it was last seen by human eyes. Tucked away in brown, leather-bound case and composed of 15 separate sheets, archivists were aware of the first edition’s survival — the only problem was that they couldn’t find it.

But the map actually benefited from its extended hibernation. The first edition retained its vibrant watercolor finish, which was preserved because it hadn't been exposed to light over a long period of time. Archivists determined that this edition was definitely among the first 50 produced, and perhaps even one of the first 10. The map is currently on display at the Geological Society in London, as part of a series that is celebrating the map’s bicentennial anniversary.

Photo credit: http://bit.ly/1GLiiuI

Further reading: http://bit.ly/1CoGbqd

http://bbc.in/1GJKSdK

http://bit.ly/1BQk2NY

Visit the map the changed the world: http://bit.ly/1C85hoo

Even more reading if you are up to it: http://amzn.to/1xyMx6f