Photo of Turn off to Franz Joseph Glacier

Glaciers into the Ocean

Since things are winding down here we are spending three days multi-beaming.   I thought I could cover an exciting geologic feature that we saw on our field trip of the South Island.   The Maori name for the glacier comes from Hinehukatere weaping for the loss of her lover who fell climbing up into the mountains and her tears freezing to form the glacier. 

Franz Joseph- Ka Roimata o Hinehukatere

Franz Joseph Glacier is located on the west side of the South Island about two thirds down.  It is presently about 19 kilometers from the sea.  Fiord lands are formed when glaciers run into the sea.  The Milford Sound is a local famous for this fiord.  Glaciers of this magnitude are absent in Colorado; although some people would argue that Arapahoe Snowfield is a glacier, and the one located furthest in the Rockies. Our mountains the Indian Peaks have been highly sculpted by glaciers into arêtes and horns. 

Check out this web site for a cool photo of Arapahoe glacier past and present- http://earthobservatory.nasa.gov/IOTD/view.php?id=5668

This one illustrates glacial landforms-

http://www.uwsp.edu/geo/faculty/Lemke/alpine_glacial_glossary/glossary.html#depositionallandforms

Franz Joseph- Ka Roimata o Hinehukatere glacier is one of the most easily accessed glaciers in the world being only 4 kilometers off of NZ Highway Six.  It is also unique for ending in a lush rainforest.

Photo of rainforest

What is an Alpine Glacier? 

Snow that doesn’t melt builds up at elevation.  Over time this snowfield starts to act like a huge conveyor belt pushing and deforming down and out to the sides.  Ice forms from huge pressures and rock and debris are scoured underneath the glacier.  When this occurs a glacier has been formed.  Glaciers can be formed with temperature changes of as little as two degrees Celsius. 

Huge glaciers also form due to cold temperatures at the poles. 

Photos of Franz Joseph Glacier

Upper

Local Colorado Glaciers

Locally glaciers were prevalent in Boulder County as late as 8,000 years ago.  Nederland is as far east as the glaciers came.  They left piles of debris around the town forming hills trending east west.  The ski area of Eldora and the Devil’s Thumb feature west of the area were all heavily glaciated.  

Characteristics of Franz Joseph Glacier

We arrived at the base of the glacier early in the evening and the cool air was sinking down the valley off of the ice.   To view the glacier we climbed Sentinel Rock.  This feature, a low hill overlooking the glacier, was left behind by the glacier due its composition of more resistant rock. 

The glacier empties into the Waiho River.  Glacial valleys have a characteristic U-shape whereas river valleys have a characteristic V-shape. 

Is Global Warming affecting the glacier? 

Due to heavy snowfall since 1997 the glacier is presently growing.  Glaciers grow or recede due to a balance of snowfall at the top and snowmelt at the bottom. 

Although, glaciers on the east side of the Southern Alps have been melting.  It is important to note that global warming doesn’t always affect systems in a predictable way.  Glacial advance has been up to a phenomenal 70 centimeters a day. 

Conclusion

With a little imagination it is not too hard to imagine the glaciers west of Boulder being like Franz Joseph.  One of my favorite exercises is to stand in one of the U-shaped valleys like in the town of Eldora and imagine the glacier towering above my head a couple thousand feet. 

This web site is helpful in understanding glaciers in our Rocky Mountain National Park.

http://www.nps.gov/features/romo/feat0001/GlcBasics.html

This image is taken from there. 

Anne Before Releasing Number # 28 

Ceremonial Releases

Over the last couple of days both Anne Sheehan and I have released Ocean Based Seismometers (OBSs). I released number twenty-seven and Anne number twenty-eight. To release the seismometer three ropes and a crane are used. Marshall the Coast Guard guy communicates to the crane operator. Paul and Ernie steady the OBS and usually Mark releases the unit. The release is done by a pulley mechanism that pops open an arm.

Dan and Crew Before Releasing #27 (photos coming soon)

Reasons to Postpone

Releasing Weather

We held our position for about two days earlier this week before dropping off number twenty-five. Wind topped out at fifty knots or sixty miles per hour and the swell’s vertical height was four and one half meters. The captain put our bow into the wind and waves and we sat in one spot using the ship’s dynamic positioning system. The Scripp’s Crew says that they have had to do this for two weeks in the past. When the seas are rough the OBS might swing around and destroy itself against the side of the ship.

Ocean Bottom Irregularities

On drop twenty-eight the ship was moved a mile north due to the bottom being too bumpy. We were on an underwater canyon. Not only is the bottom irregular it is prone to the drifting of sediments that could fill up the instrument.

Photo of Dan getting ready to release

Photo of Anne releasing