Thursday, 11 November 2010

Friday, 5 November 2010

Wednesday, 3 November 2010

JOHN DAY MAMMAL FOSSIL FIELD TRIP


More than a 100 groups of mammals have been found in the early Miocene (37 – 20 mya) John Day Formation near Kimberly, Oregon. I'm planning a field trip this July to collect in the fossiliferous strata that have yielded beautifully preserved speciments of many of the animals we see domesticated today. Dogs, cats, swine and horses are common. Oreodonts, camels, rhinoceras and rodents have also been found in this ancient deciduous forested area.


Here my talented young paleontologist cousin Spencer is holding a well preserved Oreodont skull.Many sites in Oregon yield beautifully preserved fossil shells laid down over 60 million years. The asteroid that hit the Gulf of Mexico at the end of the Cretaceous caused a seafloor rift that split ancient Oregon. The massive hole left behind as the coastal lands slid northward filled in with sediment, refilling the basin.

These marine sediments were uplifted around the time of the birth of Oregon's Coastal Range. Easily collected and identified (since they look mightly similar to their modern cousins) you can dig for marine fossils all along Oregon's beachfront. I'll post some photos when I return from collecting later this year.

Tuesday, 2 November 2010

IMPOSING WHITE PEAKS: THE CARIBOO GROUP

We soak up the breathtaking views after a long morning's paddle. The east and south sides of our route are bound by the imposing white peaks of the Cariboo Mountains, the northern boundary of the Interior wet belt, rising up across the Rocky Mountain Trench, and the Isaac Formation, the oldest of seven formations that make up the Cariboo Group. Some 270 million plus years ago, had one wanted to buy waterfront property in what is now British Columbia, you’d be looking somewhere between Prince George and the Alberta border. The rest of the province had yet to arrive but would be made up of over twenty major terranes from around the Pacific. The rock that would eventually become the Cariboo Mountains and form the lakes and valleys of Bowron was far out in the Pacific Ocean, down near the equator.

With tectonic shifting, these rocks drifted north-eastward, riding their continental plate, until they collided with and joined the Cordillera in what is now British Columbia. Continued pressure and volcanic activity helped create the tremendous slopes of the Cariboo Range we see today with repeated bouts of glaciation during the Pleistocene carving their final shape. Warm and dry with bellies filled full of soup and crisps, we head back out to explore more of nature's bounty.

Monday, 1 November 2010