On June 18 Peter Spaans and I visited the site where the Canal Flats fireball hit, on the Middle White River. Here are some photos of the terrain there. For a closer look, right click on the photo and open it in a new tab
[Map_FireballArea_sm2.jpg] Map showing closeup of the strewn field ellipse. The centre of ellipse marked at “C”. We parked at “P” at a creek at 4.6km.
“Strewn Field” Distribution: Dr. Hildebrand assumes the meteor fragments are scattered in this elliptical area 3km wide by 5 km long, on a logged hillside on the Middle White River. Anything that hit on the East side of the river, would be on a narrow shelf of flat rock, with high rocky cliffs above and bluffs below. The heavier “three pieces” would likely travel to the far end of the ellipse across the river, with 1 and 2kg fragments near the centre, and lighter fragments not travelling as far, scattered along the Western edge.
Russell Ridge: [RussellPanMidBluff1_1537-38-39.JPG] photo of the Western Ridge from half way up the East river bluffs, looking Northwest towards Sinna Creek where it cuts through the notch in Russell Ridge and enters the Middle White River. Note all the dead trees from the forest fire of 2003. The meteor would have smoked in just over the ridge, hitting like shotgun pellets all along Sinna Creek and these bluffs; smacking into ten foot deep snow banks at a terminal velocity of about 200 to 300 km/h. (Initial velocity when it entered the atmosphere was slow for a meteor, around 15km/s, the average fireball enters at 20km/s. For comparison, the space station orbits at 8km/s).
[BluffsWhiteREast_1534sm.JPG] Looking East to the Lancaster Bluffs along the river, from a spot on the old horse trail beside the river. This is where the bigger chunks of meteorite would have hit.
Bigger view of Lancaster Bluffs on the East, with Marconi Peak hidden behind them, from up on Russell ridge where we parked. [PanBluffsE28mm_1526-27-28.JPG]
It’s pretty tangled at the meteor site. There are dead trees blown over from an old forest fire, and a dense crowd of 6 foot tall pine trees newly growing, and a river and four creeks running through it. But a little bit of paradise to hike in, once you’re down on an old horse trail paralleling the river. We gave up on the higher logging areas because of the crowds of small pine trees, and went down to the open river bluffs at the front third of the impact “ellipse” at 5,050 ft. More likelihood there of finding big chunks, and it’s not clogged with close-packed pine trees. The road to the Maiyuk Rec Site at 68km is washed out just before the Mid White bridge, so we crossed the river here over a fallen log.
[LogBridgePete_1536sm.jpg] That’s Peter Spaans crossing the log in the photo. Pete used to work as lab instructor in the Physics Lab at the College back in the 1990s. I found about eight odd looking black rocks but none were attracted to a magnet. And found tasty red strawberries, elk tracks, bear scat. No mosquitoes. The trip was worth it just for the mountain scenery there. Solid limestone mountains rising with sheer slabs of snow tipped peaks. Birds singing, elk, deer, rabbits, porcupines and other wildlife.
Note that there’s a fellow working there for CanFor with a mulcher with caterpillar tracks, cutting four foot wide swathes into the densely planted pine trees for spacing purposes.
Middle Fork Rec Site: Via main road, go to White Swan Lake, which is by Canal Flats, BC (near Invermere BC in the Rocky Mountain Range of the East Kootenay’s.). Follow the gravel logging road to the Middle Fork Rec Site just past Seeta Creek at KM66 on the White Middle fork of the White River Forest Service Road. There was a forest fire there in 2003, and it has been logged since, but the Middle Fork trail was cleared in Aug 2014. At 67km leave the main road and turn left on the Sinna Creek logging road 0.9 km past the Seeta Creek bridge. From there, go 3.1km to reach the edge of the ellipse. The centre of ellipse marked on the map as “C”. We parked at “P” at a creek at 4.6km; crossed it and walked down the next dry creek bed to the Lancaster bluffs.
View from 60km looking North, our destination in sight. [Pan_RussellJoffreMarconi_60km.jpg] That teepee mountain on the centre left is Russell Peak. Snow and glacier covered Mt. Joffre and Mt. Nivelle at centre, and Mt. Marconi at right centre, behind Lancaster bluffs.
WHAT TO LOOK FOR: Carbonaceous Chondrites: comprise only about 2 percent of meteorites known to have fallen to Earth, are typically difficult to recover because they easily break down during entry into Earth’s atmosphere and during weathering on the ground. Look for black or dark grey rocks that a magnet will stick to. The surface may have a thin grayish fusion crust (a thin melted layer one or two millimetres thick) and scattered thumb sized hollows (worn away by atmospheric friction ablation, called regmaglypts). Although some rarer meteorites like the Tagish Lake meteorite looked like charcoal briquettes.
Ignore layered sedimentary rocks (shale, limestone, dolomite) since these require an ocean to form, and this wouldn’t be found on an asteroid in outer space. Also, if it has holes or bubbles inside (like pumice) that was likely from lava flows (basalt-magma) cooled with trapped volcanic gases, on Earth (although there are rare exceptions: a large asteroid like Vesta had volcanoes). Also, ignore rocks containing quartz or calcite, since they form in high pressure, hot watery solutions.
Magnets: Since a lot of carbonaceous chondrite types (CH, CI, CM, CB) contain iron oxides like magnetite, and some metal rich ones contain nickel-iron chondrules, a rare-earth magnet should stick to most. Dr. Hildebrand says: “Even the hydrated carbonaceous chondrite meteorites would stick to a magnet; something like a CV4 like Allende has the least ferro magnetic phases and might not stick, but that lithology looks v. much like meteorites and I would have guessed that this rock was weaker than CV (not that I really know). Only thing to add would be to keep an eye out for a pile of debris rather than just a solid stone – the hydrated lithologies would probably have started to break up by now.”
Photo: from Wikipedia showing some carbonaceous chondrites. From left to right: type CV4: Allende, C2: Tagish Lake (in sample bag on white paper) and CM: Murchison. Chondrite means that inside the rock are silicate chunks ranging in size from 0.3mm to 10mm, surrounded by a fine-grain black rock matrix. The chunks are usually olivine (a magnesium iron silicate common on Earth but quickly weathered) or the chunks can be nickel-iron metal. The black rock matrix is made of hydrous phyllosilicates similar to terrestrial clays, sulfides, and oxidized iron in the form of magnetite. Many contain high percentages (3% to 22%) of water, as well as organic compounds (like bitumen). However there are many types and they are complex and fairly challenging to describe, so for more detail, see: http://www.meteorite.fr/en/classification/carbonaceous.htm, and http://Wikipedia.org/wiki/carbonaceous_chondrite
Value: If a hiker finds a piece, it could be worth a lot of bucks per gram or it may be disappointing. Common iron meteors are only $.50/gram to $5/gram, rarer stony meteorites $2 to $20/gram, and really rare ones $100 or $1000/gram or more, depending if they have embedded gems or if they’re from Mars or the Moon. And some meteors are dense and heavy, so they go a long way. For example, back in 2000, the rare carbonaceous chondrite meteor that landed on frozen Tagish Lake on the B.C.-Yukon border brought Jim Brook, the lodge owner who found it an estimated $850,000. The University of Alberta, with Canada’s second-largest meteorite collection, bought most of the meteorite. For sample meteorite pricing, see http://www.meteorlab.com/METEORLAB2001dev/offering21o.htm The Washington University in St. Louis has a great webpage showing all sorts of meteorites at http://meteorites.wustl.edu/id/metal2.htm.
If you do find a possible meteorite, send a photo to Dr. Hildebrand at the University of Alberta in Calgary. Note that American Meteor hunters have to report to the Canadian Customs, Canada has export restrictions on them.
[meteorite_flow_chart.gif] Above is a flow chart guide designed by Deborah Guedes in Brazil to help identify a meteorite. http://www.lpi.usra.edu/meetings/metsoc2010/pdf/5357.pdf “Regmaglypts” are those worn-away thumb sized hollows in the surface.
Rick Nowell Astronomy Lab Tech College of the Rockies Cranbrook, BC