Saturday, May 31, 2014

[Geology2] An ancient battle: A 900-pound croc takes on a 58-foot snake



An ancient battle: A 900-pound croc takes on a 58-foot snake

An ancient, 16-foot, 900-pound crocodile may have been overmatched by a monster snake that swam in the same rivers 60 million years ago.

A new crocodilian species lived in freshwater rivers 60 million years ago, in close proximity to Titanoboa, a monster snake that would have been a formidable threat, says Jonathan Bloch.

A new crocodilian species lived in freshwater rivers 60 million years ago, in close proximity to Titanoboa, a monster snake that would have been a formidable threat, says Jonathan Bloch. "Every once in a while, there was likely an encounter between Anthracosuchus and Titanoboa. Titanoboa was the largest predator around and would have tried to eat anything it could get its mouth on." Image credit: University of Florida

The newly named reptile, Anthracosuchus balrogus, which had an unusually blunt snout for species in the dyrosaurids family, was unearthed from the same layer of rock as the 58-foot Titanoboa in the Cerrejon coal mine of northern Colombia.

The species opens a window to the early adaptability and diversity of tropical crocodyliforms, which may help scientists better understand how living crocodiles adapt to changing environments today, says lead author Alex Hastings, a postdoctoral researcher at Martin Luther Universität Halle-Wittenberg and former graduate student in the geological sciences department at the University of Florida and at the Florida Museum of Natural History.

"It quickly became clear that the four fossil specimens were unlike any dyrosaur species ever found," he says.

The species' short snout paired with large jaw muscles typical of dyrosaurids, would give it an incredibly powerful bite, Hastings says. "Everyone thinks that crocodiles are living fossils that have remained virtually unchanged for the last 250 million years. But what we're finding in the fossil record tells a very different story."

Researchers were stunned when they first saw the new species, says Jonathan Bloch, a coauthor of the study, published in the journal Historical Biology, and associate curator of vertebrate paleonotolgy at the Florida Museum.

"We couldn't believe it had such a boxy, short skull and that it was still a dyrosaur," he says. "It really busts the mold for these animals. It is such a completely different looking beast than we've seen for these crocodile-like animals."

Survived the extinction

The study of dyrosaurids in Cerrejon is providing a better understanding of the early history of crocodiles in the Neotropics, says paleobotanist and coauthor Carlos Jaramillo of the Smithsonian Tropical Research Institute. "This new finding showcases the wide range of ecological variation that tropical crocodiles already had by 60 million years ago—much larger than modern Neotropical crocodile faunas."

The animal is the third new species of ancient crocodilian pulled from Cerrejon, one of the world's largest open-pit coal mines. Originating in Africa, the dyrosaurids swam across the Atlantic Ocean to South America about 75 million year ago. The family somehow survived the extinction event that wiped out the dinosaurs and persisted to become a top predator, Hastings says.

"This group offers clues as to how animals survive extinctions and other catastrophes. As we face climates that are warmer today, it is important to understand how animals responded in the past. This family of crocodyliforms in Cerrejon adapted and did very well despite incredible obstacles, which could speak to the ability of living crocodiles to adapt and overcome."

A 'formidable threat'

The crocodyliforms that lived in the Cerrejon ecosystem during the Paleocene, when temperatures were higher than today, thrived and grew to enormous sizes, Bloch says. Dyrosaurids were commonly ocean-dwellers, but the new species lived in freshwater rivers, ate turtles and fish, and would have lived in close proximity to Titanoboa.

However, the giant snake would have been a formidable threat to A. balrogus with the tremendous grip of its constricting coils.

"Every once in a while, there was likely an encounter between Anthracosuchus and Titanoboa," Bloch says. "Titanoboa was the largest predator around and would have tried to eat anything it could get its mouth on."

The exceptionally short and robust snout of A. balrogus is probably related to its wide range of diet, says Stéphane Jouve, a paleontologist with the Natural History Museum of Marseille. Although some species of dyrosaurids have slightly different morphologies, only A. balrogus has a short and relatively wide snout that resembles some existing crocodiles.

"In the future, it would be interesting to determine if the short-snouted species forms an independent dyrosaurid group, or an intermediate morphology between the slender-snouted pholidosaurids and slender-snouted dyrosaurids," he says.

These ancient species from the oldest rain forest are exposing the foundations of tropical ecosystems, Bloch says. A. balrogus was ecologically very similar to crocodiles in the Amazon today, while Titanoboa was somewhat like a modern anaconda—aquatically adapt, with a diet of crocodyliforms, turtles, and fish.

"In a lot of ways, the ecological diversity that we see in these dyrosaurids mirrors the overall diversity that we see in crocodiles today."

http://earthsky.org/earth/an-ancient-battle-a-900-pound-croc-takes-on-a-58-foot-snake?utm


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[Geology2] Australia's deadly eruptions were reason for the first mass extinction



Australia's deadly eruptions were reason for the first mass extinction

Date:
May 30, 2014
Source:
Curtin University
Summary:
Ancient volcanic eruptions in Australia 510 million years ago significantly affected the climate, causing the first known mass extinction in the history of complex life. Scientists used radioactive dating techniques to precisely measure the age of the eruptions of the Kalkarindji volcanic province.

Glass House Mountains National Park in Australia. A Curtin University researcher has shown that ancient volcanic eruptions in Australia 510 million years ago significantly affected the climate, causing the first known mass extinction in the history of complex life.
Credit: © jovannig / Fotolia



A Curtin University researcher has shown that ancient volcanic eruptions in Australia 510 million years ago significantly affected the climate, causing the first known mass extinction in the history of complex life.

Published in the journal Geology, Associate Professor Fred Jourdan from Curtin's Department of Applied Geology, along with colleagues from several Australian and international institutions, used radioactive dating techniques to precisely measure the age of the eruptions of the Kalkarindji volcanic province -- where lavas covered an area of more than 2 million square kilometres in the Northern Territory and Western Australia.

Dr Jourdan and his team were able to prove the volcanic province occurred at the same time as the Early-Middle Cambrian extinction from 510-511 million years ago -- the first extinction to wipe out complex multicellular life.

"It has been well-documented that this extinction, which eradicated 50 per cent of species, was related to climatic changes and depletion of oxygen in the oceans, but the exact mechanism causing these changes was not known, until now," Dr Jourdan said.

"Not only were we able to demonstrate that the Kalkarindji volcanic province was emplaced at the exact same time as the Cambrian extinction, but were also able to measure a depletion of sulphur dioxide from the province's volcanic rocks -- which indicates sulphur was released into the atmosphere during the eruptions.

"As a modern comparison, when the small volcano Pinatubo erupted in 1991, the resulting discharge of sulphur dioxide decreased the average global temperatures by a few tenths of a degree for a few years following the eruption.

"If relatively small eruptions like Pinatubo can affect the climate just imagine what a volcanic province with an area equivalent to the size of the state of Western Australia can do."

The team then compared the Kalkarindji volcanic province with other volcanic provinces and showed the most likely process for all the mass extinctions was a rapid oscillation of the climate triggered by volcanic eruptions emitting sulphur dioxide, along with greenhouse gases methane and carbon dioxide.

"We calculated a near perfect chronological correlation between large volcanic province eruptions, climate shifts and mass extinctions over the history of life during the last 550 million years, with only one chance over 20 billion that this correlation is just a coincidence," Dr Jourdan said.

Dr Jourdan said the rapid oscillations of the climate produced by volcanic eruptions made it difficult for various species to adapt, ultimately resulting in their demise. He also stressed the importance of this research to better understand our current environment.

"To comprehend the long-term climatic and biological effects of the massive injections of gas in the atmosphere by modern society, we need to recognise how climate, oceans and ecosytems were affected in the past," he said.


Story Source:

The above story is based on materials provided by Curtin University. Note: Materials may be edited for content and length.


Journal Reference:

  1. F. Jourdan, K. Hodges, B. Sell, U. Schaltegger, M. T. D. Wingate, L. Z. Evins, U. Soderlund, P. W. Haines, D. Phillips, T. Blenkinsop. High-precision dating of the Kalkarindji large igneous province, Australia, and synchrony with the Early-Middle Cambrian (Stage 4-5) extinction. Geology, 2014; 42 (6): 543 DOI: 10.1130/G35434.1


Curtin University. "Australia's deadly eruptions were reason for the first mass extinction." ScienceDaily. ScienceDaily, 30 May 2014. <www.sciencedaily.com/releases/2014/05/140530124327.htm>.

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[Geology2] Lassen Volcano Eruption Images 1914-1917





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[californiadisasters] On This Date In California Weather History (May 31)



2001: San Jose reported a high temperature of 101° F.

2001:
Fresno reached 106° F, marking the 9th time this month the high reached into the triple digits.
This set a record for the most triple digit high temperatures in May.

2001: It was 93° F in Idyllwild, the highest temperature on record for May.
This also occurred on 5.29.1984.
It was 91° F in Palomar Mountain, the highest temperature on record for May.
This also occurred on 5.28.2003.

1998: Fresno reached a high of only 85° F and in Bakersfield the high reached 84° F.
This was the warmest reading of the month at both locations and only the 3rd May on record in both cities that the high temperature never cracked 90° (also occurred in May 1917 and 1961).

1987: The Morse Wildfire burned 166 acres and destroyed 31 homes near Pebble Beach.

1971: 8" of snow fell at Glenbrook, its all-time record one-day total for May.

1967: 8" of snow fell at Sierraville.

1961: Virginia City, NV, recorded 1.9" of precipitation.

1910: Earliest 110° F high temperatures on record at Fresno and Bakersfield.
Also the highest temperatures ever recorded at both locations for May.
In Lemon Cove, the high reached a sweltering 118° F, the highest on record here in May.

Source: NWS San Francisco/Monterey, Hanford, Reno & San Diego

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[californiadisasters] Sundowner Wind Advisory (5/30/14-PM)



SANTA BARBARA COUNTY SOUTH COAST-SANTA BARBARA COUNTY MOUNTAINS-  INCLUDING THE CITIES OF...SANTA BARBARA...MONTECITO...  CARPINTERIA...SAN MARCOS PASS...SAN RAFAEL WILDERNESS AREA...  DICK SMITH WILDERNESS AREA  951 PM PDT FRI MAY 30 2014    ...WIND ADVISORY REMAINS IN EFFECT UNTIL 3 AM PDT SATURDAY...    * WINDS AND TIMING...AREAS OF NORTHWEST TO NORTH WINDS 15 TO 30    MPH WITH GUSTS UP TO 45 MPH...STRONGEST THROUGH AND BELOW    PASSES AND CANYONS WEST OF SANTA BARBARA. WINDS DIMINISHING LATE    TONIGHT.    * IMPACTS...MAJOR ROADWAYS THAT COULD BE AFFECTED INCLUDE HIGHWAYS    101 AND 154...ESPECIALLY NEAR GAVIOTA PASS AND SAN MARCOS PASS.    PRECAUTIONARY/PREPAREDNESS ACTIONS...    WHEN DRIVING...USE EXTRA CAUTION. BE PREPARED FOR SUDDEN GUSTY  CROSS WINDS.

NWS LOS ANGELES/OXNARD
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[californiadisasters] On This Date In California Weather History (May 30)



2002: Thunderstorms dropped 1.01" of rain at the Hanford Airport in just 21 minutes in the afternoon resulting in street flooding in the city.
In just an hour, some 260 lightning strikes were recorded in the central and southern San Joaquin Valley.

2001: Ben Lomond had a high temperature of 105° F.

1991: High winds blasted Las Vegas darkening power for 100,000 customers, blowing over a large rocket sign at the Vegas World Casino and tearing off tips of turrets on the Excalibur.

1991: China Lake NAS clocked an 89 mph gust from the west, tied for the highest on record here (also had an 89 mph gust on January 14, 1950).

1984: Remarkably, on the same day of the highest maximum and minimum temperatures, Borrego Springs also recorded its record rainfall for this day.

1984: Intense winds, gusting as high as 60 mph, blew across Kern County shattering windows, knocking air conditioning units off roofs and toppling trees.
A number of utility poles also were knocked down, some which were leveled by "a wall of wind and dust".
On this same date, Fresno only dropped to 76° F for low, making it the warmest minimum temperature on record for the month of May.

1983: Very heavy rain caused a mudslide on Slide Mountain.
The resulting debris flow that was sent down Ophir Creek forced the closure of U.S. Highway 395.

1918: It was 32° F in Victorville, the latest date in the season with a freezing temperature on record.

Source: NWS San Francisco/Monterey, Hanford, Reno, Las Vegas, & San Diego

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Friday, May 30, 2014

[Geology2] Volcano News 05/30/2014



 

Volcano erupts in Indonesia, farmers evacuated

IANS  |  Jakarta 

A volcano errupted in Indonesia Friday, forcing evacuation of farmers from the areas on the slope of the volcano, official said.

A powerful burst of hot ashes erupted from the rumbling Mount Sangiang in West Nusatenggara province, Xinhua reported.

The volcano, located in a small island of Bima district, spewed ashes into the sky at 3.55 p.m., Muhammad Hendrasto, head of the National Volcanology Agency, said.

"Scores of farmers cultivating the land in the island, seven km from the crater, have been told to leave the area since this morning. And they have been warned not to re-enter the island during the eruption period," he told Xinhua by phone.

Authorities had put Mount Sangiang on high alert since June 14, 2013, Hendrasto said.

"With this eruption, we are likely to raise the alert level to the second highest," he said.

So far, no similar order had been issued for evacuation of those living in the nearby island, according to Hendrasto.

Mount Sangiang is among 129 active volcanoes in Indonesia, which is prone to seismic upheaval due to its location on the Pacific "Ring of Fire", an arc of volcanoes and fault lines encircling the Pacific Basin.

In February, more than 15 people were killed and tens of thousands of others were internally displaced when the volcano erupted intermittently.

http://www.business-standard.com/article/news-ians/volcano-erupts-in-indonesia-farmers-evacuated-114053001413_1.html

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VOLCANO WATCH: Assessing Lava-Flow Risk for Populated Areas

Posted on May 30th, 2014

by Hawaiian Volcano Observatory

VOLCANO WATCH: Assessing Lava-Flow Risk for Populated Areas Scientists are using satellite imagery to assess potential damage from homes in areas susceptible to lava flows, such as the Puna subdivision of Leilani Estates which lies on the east rift zone of Kilauea volcano. Google Earth image.
Posted on May 30th, 2014

by Hawaiian Volcano Observatory

Hawai'i County is the fastest-growing region in the State of Hawaii. Its relatively inexpensive real estate, along with population growth, spurs more and more construction on the flanks of its active volcanoes.

With growth comes increased risk from lava-flow hazards. Estimating the potential damage from future lava flows to infrastructure or development poses serious challenges to emergency managers.

A new tool that can help identify structures in a lava flow's path is image classification applied to satellite imagery. This technique, combined with estimates of future lava-flow coverage, enables civil authorities to know the number of structures in any geographic region that are threatened by lava flows.

Image classification is widely used in agricultural studies to create land-use maps, but it has not been used extensively in volcanic hazards assessments. We are testing the applicability of the image classification technique––using remote sensing images, like those found on Google Earth––in combination with geographic information systems software. We attempted to automatically locate and classify structures using both supervised and unsupervised classification schemes.

In the supervised classification schemes, the user is able to select those areas in an image that correspond to forest, houses, or roads and use these classes to produce a classified image. In unsupervised classification, which is not dependent on the user, the algorithm auto-selects the features. We used both methods on different regions of the Big Island to estimate the numbers of structures present and checked their accuracy by manually counting the number of structures.

For two test areas where there is high risk from future lava flows—Hawaiian Ocean View Estates (HOVE) and Leilani Estates—the results of the supervised classification were more accurate than those of the unsupervised technique. The supervised yielded 85 percent for HOVE and 78 percent for Leilani, compared with 75 and 64 percent, respectively, for unsupervised image classifications.

For two other test cases, the unsupervised classifications yielded better results––92 and 95 percent––in detecting structures than the supervised classifications, which yielded 82 and 85 percent. Therefore, while it may be difficult to know in advance which classification scheme is more accurate than the other, the results give us a reasonable degree of confidence that these techniques could be useful.

The size of the area and the structure density appear to influence whether one classification scheme might be more accurate than the other. For example, when assessing a small area with a high structure density, the unsupervised classification appears to be more accurate than the supervised classification. On other hand, the supervised classification yields more accurate results in a larger area with relatively low structure density. We will explore the reasons for the differences in future tests.

The difference between the algorithms lies in the way the classes are grouped. For the supervised classification, the user defines each feature type or class beforehand and builds a signature file with this information. Different colors define different types of features, such as vegetation, roads, or houses. In unsupervised classification schemes, each pixel is compared with the color class or signature of the feature type. Then all the pixels in the study area are assigned automatically to a known class to which it has the highest probability of being a member.

Using supervised and unsupervised classification schemes for each assessment might combine the strengths of both methods. For example, we could use the unsupervised classification first to produce a signature file and then use that signature file to run the supervised classification.

We continue to refine our classification algorithms and further enhance them by eliminating false identifications. Our study shows that classifying satellite images can be useful in estimating the number of structures potentially in harm's way. Ultimately, it will enhance our ability to assess our island's vulnerability to future lava flows.

Kīlauea activity update

A lava lake within Halema'uma'u produced nighttime glow that was visible via HVO's Webcam during the past week. The lava lake level dropped during deflation that began on May 10 and remained relatively low for the next two weeks. Over the past week, the lava level rose with summit inflation. By May 29, the lava level had reached 43 m (140 ft) below the rim of the Overlook crater.

On Kīlauea's East Rift Zone, the Kahauale'a 2 flow remains active but has diminished greatly in vigor over the past two weeks. The flow front has stalled at 8.8 km (5.5 miles) northeast of its vent on Pu'u 'Ō'ō, with very weak surface flows active behind the flow front. Several small spatter cones within Pu'u 'Ō'ō crater continue to produce glow.

There were three earthquakes reported felt in the past week within the State of Hawaii. On May 25, 2014, at 5:32 a.m., HST, a magnitude-2.9 earthquake occurred 3 km (2 mi) southeast of Captain Cook at a depth of 7 km (5 mi). On May 28 at 4:40 p.m., a magnitude-3.8 earthquake occurred 68 km (42 mi) northeast of Kailua, O'ahu, at a depth of 30 km (19 mi). On May 28 at 11:03 p.m., a magnitude-3.2 earthquake occurred 4.8 km north of Kawaihae at a depth of 23 km (15 mi).

http://bigislandnow.com/2014/05/30/volcano-watch-assessing-lava-flow-risk-for-populated-areas/

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[Geology2] Lassen Peak 100 Years Ago to National Park



(and my blog is mentioned in this report, which is why I nabbed it)

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[Geology2] UK Paleontologists Find Huge Tooth Fossil of Dakosaurus maximus



UK Paleontologists Find Huge Tooth Fossil of Dakosaurus maximus

May 30, 2014 by Sci-News.com

Dr Mark Young from the University of Edinburgh and his colleagues have discovered a unique fossilized tooth belonging to Dakosaurus maximus, a prehistoric relative of modern crocodiles that lived in the shallow seas of what is now Europe during the Jurassic period, about 150 million years ago.

A tooth of Dakosaurus maximus in lingual, labial, basal and apical view. Scale bar - 1 cm. Image credit: Mark T. Young et al.

A tooth of Dakosaurus maximus in lingual, labial, basal and apical view. Scale bar – 1 cm. Image credit: Mark T. Young et al.

Dakosaurus maximus measured up to about 4.5 m long and belonged to a family of marine animals known as thalattosuchians.

The unusual shape of the animal's skull and teeth suggests it ate similar prey to modern-day killer whales.

The animal would have used its broad, short jaws to swallow large fish whole and to bite chunks from larger prey.

A huge, about 5.5 cm long, tooth of Dakosaurus maximus was collected from Kimmeridge Clay Formation in Dorset, England. It is the largest known British specimen of the genus Dakosaurus.

Life restoration of Dakosaurus maximus, center, and two Gnathosaurus subulatus. Image credit: Dmitry Bogdanov / CC BY 3.0.

Life restoration of Dakosaurus maximus, center, and two Gnathosaurus subulatus. Image credit: Dmitry Bogdanov / CC BY 3.0.

"The circumstances in which the fossil was found were unusual – it was dredged from the sea floor rather than being found on the shore or dug up," said Dr Young, who is the lead author of a paper published in the journal Historical Biology.

"Given its size, Dakosaurus had very large teeth. However, it wasn't the top marine predator of its time, and would have swum alongside other larger marine reptiles, making the shallow seas of the Late Jurassic period exceptionally dangerous."

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Mark T. Young et al. Largest known specimen of the genus Dakosaurus (Metriorhynchidae: Geosaurini) from the Kimmeridge Clay Formation (Late Jurassic) of England, and an overview of Dakosaurus specimens discovered from this formation (including reworked specimens from the Woburn Sands Formation). Historical Biology: An International Journal of Paleobiology, published online May 16, 2014; doi: 10.1080/08912963.2014.915822

http://www.sci-news.com/paleontology/science-tooth-fossil-dakosaurus-maximus-01954.html

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[Geology2] Four-billion-year-old rocks yield clues about Earth's earliest crust



Four-billion-year-old rocks yield clues about Earth's earliest crust

Date:
May 29, 2014
Source:
University of Alberta
Summary:
It looks like just another rock, but what researchers are examining is a four-billion-year-old chunk of an ancient protocontinent that holds clues about how Earth's first continents formed. Continents today form when one tectonic plate shifts beneath another into Earth's mantle and cause magma to rise to the surface, a process called subduction. It's unclear whether plate tectonics existed 2.5 billion to four billion years ago or if another process was at play.

A sample of ancient rock from the Acasta Gneiss Complex in the Northwest Territories.
Credit: Image courtesy of University of Alberta



It looks like just another rock, but what Jesse Reimink holds in his hands is a four-billion-year-old chunk of an ancient protocontinent that holds clues about how Earth's first continents formed.

The University of Alberta geochemistry student spent the better part of three years collecting and studying ancient rock samples from the Acasta Gneiss Complex in the Northwest Territories, part of his PhD research to understand the environment in which they formed.

"The timing and mode of continental crust formation throughout Earth's history is a controversial topic in early Earth sciences," says Reimink, lead author of a new study in Nature Geoscience that points to Iceland as a solid comparison for how the earliest continents formed.

Continents today form when one tectonic plate shifts beneath another into Earth's mantle and cause magma to rise to the surface, a process called subduction. It's unclear whether plate tectonics existed 2.5 billion to four billion years ago or if another process was at play, says Reimink.

One theory is the first continents formed in the ocean as liquid magma rose from Earth's mantle before cooling and solidifying into a crust.

Iceland's crust formed when magma from the mantle rises to shallow levels, incorporating previously formed volcanic rocks. For this reason, Reimink says Iceland is considered a theoretical analogue on early Earth continental crust formation.

Ancient rocks 3.6 to four billion years old

A sample of ancient rock from the Acasta Gneiss Complex in the Northwest Territories

Working under the supervision of co-author Tom Chacko, Reimink spent his summers in the field collecting rock samples from the Acasta Gneiss Complex, which was discovered in the 1980s and found to contain some of Earth's oldest rocks, between 3.6 and four billion years old. Due to their extreme age, the rocks have undergone multiple metamorphic events, making it difficult to understand their geochemistry, Reimink says.

Fortunately, a few rocks -- which the research team dubbed "Idiwhaa" meaning "ancient" in the local Tlicho dialect -- were better preserved. This provided a "window" to see the samples' geochemical characteristics, which Reimink says showed crust-forming processes that are very similar to those occurring in present-day Iceland.

"This provides the first physical evidence that a setting similar to modern Iceland was present on the early Earth."

These ancient rocks are among the oldest samples of protocontinental crust that we have, he adds, and may have helped jump-start the formation of the rest of the continental crust.

Reimink, who came to the U of A to work with Chacko, says the university's lab resources are "second to none," particularly the Ion Microprobe facility within the Canadian Centre for Isotopic Microanalysis run by co-author Richard Stern, which was instrumental to the discovery.

"That lab is producing some of the best data of its kind in the world. That was very key to this project."


Story Source:

The above story is based on materials provided by University of Alberta. The original article was written by Bryan Alary. Note: Materials may be edited for content and length.


Journal Reference:

  1. Jesse R. Reimink, Thomas Chacko, Richard A. Stern, Larry M. Heaman. Earth's earliest evolved crust generated in an Iceland-like setting. Nature Geoscience, 2014; DOI: 10.1038/ngeo2170


University of Alberta. "Four-billion-year-old rocks yield clues about Earth's earliest crust." ScienceDaily. ScienceDaily, 29 May 2014. <www.sciencedaily.com/releases/2014/05/140529112057.htm>.

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[Geology2] Landslide-created lake endangers Mesa County town



Lake forming near landslide could break and rush towards Collbran. Residents of the area are warned to be ready to evacuate.

(Photo: Jim Terry)

GOLDEN – The massive landslide that poured down from Colorado's Grand Mesa on Sunday reshaped part of the geography in that area and also created a brand new lake.

According to members of the United States Geological Survey based out of Golden, a makeshift dam holding that lake in place has the potential to break and flood nearby creeks as well as the town of Collbran.

"Our fear is that the water breaching might mix with a lot of [debris] and form a large volume, high speed, debris flow – going down West Salt Creek and then eventually into ... Plateau Creek that goes in to Collbran," said Edwin Harp, a research geologist with the USGS in Golden.

Harp has worked for the USGS for more than 40 years. He doesn't recall ever seeing a lake form behind a landslide in Colorado.

"Nothing where a big lake formed. There may have been small streams, but nothing as big as this has happened," Harp explained.

No one's quite sure how large the lake is or how fast it's growing. Geologists say two waterfalls are pumping more water into the lake every second.

"We really haven't evaluated how big the body of water is behind it and how big it's going to be before it overtops, but we're trying to work out the uncertainties on that so we can decide how far downstream there might be a problem," said Harp.

The big concern is whether the lake water is mixing with shale from the landslide.

"We don't think the shale [from] the landslide damage is really stable. We suspect it will erode and cut through. But the question is 'how fast will it breach? Will it breach really catastrophically or will it be somewhat slower?'" Harp added.

The USGS has two geologists at the site. They were collecting information Thursday afternoon, and they plan to present it to the county and state.

"That takes some time, and we might not have that time to do all that before some breaching occurs. In which case, we'll have to make a very conservative judgment as to how many people need to get out of the way of it and what area will be affected," Harp said.

It's unclear when the dam will break or if the water will breach. Even if it does, Harp says it might not be too devastating. However, in situations like this, Harp says it's always a good idea to plan for the worst-case scenario.

"If we know sometime approximately when the dam breach is going to occur, we need to get out of the way, let it happen and then go back and reassess whether we can get back to our houses or not," he said.

Hundreds warned to be ready to evacuate

During a public meeting Thursday evening, geologists warned residents of the area that they should be ready to evacuate. They said they do not know for sure if a second slide will happen but if does, Plateau Creek is most at risk.

http://www.9news.com/story/weather/2014/05/29/landslide-lake-rush-collbran/9728531/
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