Geobulletin alpha

Travels in Cascadia: Threading the Needle on Hurricane Ridge 

Leading a field studies trip is a stress-filled enterprise. There are the big things to worry about: auto accidents, injuries, conflicts with law enforcement, lost reservations, and those sorts of things. But those thankfully don't happen much. But weather does happen, and field studies trips tend to be tightly scripted affairs with not much room for weather-related complications. Yet

A Look Back at Ten Years of Geotripping: Driving Through the Most Dangerous Plate Boundary in the World 

Driving through the most dangerous (kind of) plate boundary in the world is actually not very easy to do. Subduction zones, with the exception of the volcanoes, are mostly deep under the sea. But Central California is a unique case, being an ancient subduction zone that has been uplifted and exposed by erosion, so that interested parties can literally drive through what once was miles

Serpentinite mélange on Marshall’s Beach 

South of the Golden Gate Bridge in San Francisco, there are beachside exposures of serpentinite mélange: tectonically sheared-out former oceanic crust accreted to western North America as part of an accretionary

Driving Through the Most Dangerous Plate Boundary in the World: A Compilation of Fear(somely cool geology) 

Without a doubt, subduction zones are the most dangerous plate boundaries on the planet. Divergent plate boundaries produce earthquakes and occasional volcanoes, but nothing on the fearsome scale of the calderas and stratovolcanoes and magnitude 9 earthquakes experienced at convergent boundaries. Transform boundaries produce earthquakes, but they are magnitudes smaller than those produced

Driving Through the Most Dangerous Plate Boundary in the World: Exploring the Belly of the Beast in the Diablo Range 

A long time ago (a few weeks; that's years in internet time) I began this series about driving through the most dangerous plate boundary in the world. Convergent boundaries with their subduction zones or gigantic thrust faults are the most dangerous boundaries that exist on the planet. We need no more reminder than the horrible tragedy that unfolded this week in Nepal. California was

Driving Through the Most Dangerous Plate Boundary in the World: Geology's Junk Drawer on the Marin Headlands 

We continue our drive through the most dangerous plate boundary in the world (past tense, since it became inactive 20 million-plus years ago), and we've arrived at the Marin Headlands, one of the most beautiful coastlines in the world, and a marvelous exposure of what I've called geology's junk drawer, the accretionary wedge of a subduction zone. The rocks of the wedge are called

Driving Across the Most Dangerous Plate Boundary in the World: These Rocks are All Wrong! 

The view from Muir Beach Overlook, midway between San Francisco and Point Reyes National Seashore Point Reyes National Seashore: Is it land's end, or ocean's end? From a human point of view, it is the former. This is the far west of North America, and you can't go any farther without a boat or plane. But if we consider the oceanic crust that was being subducted beneath the continent

Driving Through the Most Dangerous Plate Boundary in the World: Reconnaissance 

We're headed on a blog adventure through the most dangerous kind of plate boundary in the world. To make things clear, the boundary we are exploring is not currently the most dangerous in the world, although it is certainly very hazardous. As described in my introduction yesterday, most subduction zones are not easy to explore. Most parts lie underwater or deep in the crust. We are

Driving Through the Most Dangerous Plate Boundary in the World: A New Blog Series 

Source: adapted from National Park Service and R. J. Lillie. 2005, Parks and Plates Before I get accused of "cable-newsing/click-baiting" with my choice of a headline, I'll amend it to say "Driving through the most dangerous kind of plate boundary in the world". Where in the world do we find the worst earthquakes, and many of the worst volcanic eruptions? Looking at maps of

Northern Convergence: The Olympics, Where a Trench Became Sky-Piercing Peaks 

Our journey through Western Canada and the Pacific Northwest began as we met with our students in the Seattle area one evening in late July. After a complicated couple of hours of meetings and negotiating van rentals (reservations three months earlier are only the preliminaries), we settled in for the night, and prepared to hit the road at 6:30 AM. We had a long day ahead that wouldn't

I'm Sorry, This Trench is Full; Those Rocks Will Have to Go Elsewhere 

Looking south from Hurricane Ridge into the heart of Olympic National Park There will be few detailed blogs these next few weeks; I'm on the road leading our Canada/Pacific Northwest field class, and I will be just a bit busy. But I can't help putting up a few photos here and there. In today's pictures we see what happens when subduction zones get out of control, so to speak. Subduction

Where the Sierra Nevada Rises From the Sea: Tomales Bay and Bolinas Lagoon 

Let's cross back onto North America for a short bit. In this off and on series about the most beautiful coastline in the world we have been jumping back and forth between the North American and Pacific plates as we followed the transform boundary called the San Andreas fault. In the last post on the Point Reyes Headland we were standing on the granitic rocks of the Sierra Nevada which

plants and rocks 

I missed December's Accretionary Wedge about plants and rocks - I really need to keep up on my geoblogosphere reading! I am not a botanist, and my knowledge of plants is generally restricted to the local ones which can cause me trouble, such as poison oak and poison ivy. I do have one piece of botanical/geological advice: If you are trying to locate pockets of soil deep enough to get a

Accretionary Wedge #61: Geo-jobs! 

For October’s Accretionary Wedge, I asked what you did in your geoscience job. Martin Bentley works in a small geotechnical engineering company in South Africa, where he does a lot of borehole logging fieldwork, along with report creation and administration. The Gallivanting … Continue reading

The Accretionary Wedge #60 – Momentous Discoveries in Geology Summary Post 

I have to admit I have been a bit lax with the summary post for AW60.  I blame turkeys. It was the Canadian Thanksgiving weekend recently and what with school, the holiday and other things blogging slipped a little lower on my list of priorities that I would like. I also had to submit a

The space tech that fell to Earth – GBinSAR! 

This is my piece for Accretionary Wedge #60 ‘Momentous Discoveries in Geology’. Enjoy! GBinSAR? What is this all about? I am going to talk about a very momentous discovery in geology, the development of a type of radar that helps … Continue reading

Momentous discoveries in oceanography 

Earlier this month, one of our network bloggers, Matt Herod, put out a call for posts on momentous discoveries in geology as part of a well-known geoscience blog carnival, The Accretionary Wedge. With so many geoscience disciplines to choose from, and an immense wealth of exciting discoveries across the Earth sciences, choosing just one momentous

Accretionary Wedge: Guidebooks Galore! 

For the August 2013 Accretionary Wedge #59, I asked anyone who reads geology guides, goes on geotourism adventures, or collects fieldtrips to review their books for the good, the bad, and the downright handy. Hollis Marriott of In the Company … Continue reading

The Accretionary Wedge #60 – Call for Posts – Momentous Discoveries in Geology 

I am lucky enough to play host to the 60th edition of the Accretionary Wedge. First, I’d just like to highlight the fact that there have been 60 previous and excellent wedges and ! WOW.  This has to be one of the best blog carnivals out there, and here is to another 60 great AW’s

Risk of Stumbling 

Evelyn at Georneys is again hosting an Accretionary Wedge, this time about signs that are geologically or geographically interesting. My contribution is not even really mine, because I didn’t take the photo myself. I have come across the picture several years ago somewhere on the net, but forgot to remember where it was or by