Winter Pursuits - planning for Spring, Summer and Fall

I’m passing the winter in my studio getting ready for another solo exhibition at a little café in Port Rexton, the Two Whales.  The opening is on September 1^st and the work can be seen until the 30th.  In 2018 I visited several beaches on the Bonavista Peninsula and found a lot of subject matter for a dozen or so paintings for the exhibition.

From reading the Geological Association of Canada Field Trip Guide, September 29 - Oct 1, 2017, titled: Depositional settings and tectonic evolution of rocks of the Bonavista Peninsula: new constraints and queries for Avalonia I found a few places with interesting rocks to paint.

From that report I discovered the beautiful and secluded Spaniard’s Cove on the road to Old Bonaventure and spent a quiet morning sketching in the sun.

I also went to Brook Point Cove and spent a few hours there sketching out that vibrant formation.  I may paint a part of it.  It’s a nice spot to sit and listen to the ocean … and the rocks.

The southwest end of Keels was equally nice. I was told it is known as the Turkish shore. On a quiet little beach I found some interesting formations  caused by water erosion. 

So...continuing with my current research...

For this new series of geologic paintings, Roaming the Proterozoic,  I am following the geological time scale from oldest to youngest Precambrian rocks on the Avalon Peninsula.  I have relied heavily on the map “Geology of the Avalon Peninsula” by Dr. Arthur King, produced in 1988.  It graces the walls of my studio and is an excellent reference source.

I’ve sketched out a sequence for myself and am filling in sites to visit in each section from information gleaned from geology reports and the Avalon Peninsula geology map.

I will be filling in the details of each location as I visit there.  This piece of gloss paper is 5 inches x 48 inches.  I anticipate several incarnations of this as I work through the formations.  

The oldest rocks on the Avalon are found in what's known in geological circles as the Harbour Main Group.  I have been researching good places to see them, off the beaten track preferably.  I have decided on Finn Hill in Colliers, the Brigus Lookout north of the Brigus lighthouse and a section along the eastern shore of Conception Bay in a place known as Duffs where there is an interesting formation of Harbour Main volcanics and an intrusion along the shoreline (more about intrusions later).

I have several reports that I found to be excellent sources of information, here are just three of them:

Late Precambrian (Hadrynian) ash-flow tuffs and associated rocks of the Harbour Main group near Colliers, Avalon Peninsula, S.E. Newfoundland - Graham Nixon, MSc thesis, 1976

Late Precambrian Ignimbrites on the Avalon Peninsula - V.S. Papezick, 1969

Late Precambrian Rocks of Eastern Avalon Peninsula, Newfoundland - A Volcanic Island Complex - C.J. Hughes and W.D. Bruckner, 1970

Finn Hill:
Finn Hill is an imposing hunk of rock on the south side of Colliers, it is immense but I’m told you can get up there.

I want to find the ignimbrite sequence described in V.J. Papezick's paper and the Masters thesis of Graham Nixon listed above.  

The Facts on File Dictionary of Earth Science gives a very long definition of an 
ignimbrite.  Here's a part of it, not verbatim, "ignimbrites are pyroclastic rocks produced from ash-flows from an exploding volcano, they have a streaky or banded appearance, can contain flattened glassy shards."  There's a lot more to the definition but that's the basic description.

The cross-section below in Papezick's report describes the rock types in each of the numbered areas.  

The descriptions of the rock are very enticing, here's a quote from his paper:

"Although the original glass is recrystallized, shard outlines are perfectly preserved and fragments of obsidian and perlite can be recognized."

Obsidian is a glassy, black volcanic rock.  I would love to see this, seems like it might be an interesting texture.

Brigus Lookout:

I found a notation on the King geology map that states the Harbour Main rocks in the area of the Brigus Lookout are +/- 622 million years old, according to the map they are pink to grey felsic tuff and agglomerate; pink to red rhyolite and welded tuff; includes minor mafic volcanic and clastic sedimentary rocks.  

The lighthouse trail is on the right, I have to head along to the left to get to these distant hunks of rock, not sure if there's a trail, not sure what I will find but it'll be a nice hike for sure.


Duffs:
Now for the intrusive part of the post:

"An intrusive rock is an igneous rock that forms by injection of magma ... into the Earth's crust and has solidified beneath the Earth's surface." [from The Facts on File Dictionary of Earth Science, 2000]. 

There is a large intrusion on the Avalon Peninsula known as the Holyrood Intrusive Suite.  The report by Hughes and Bruckner describes this formation of granitic rocks. There is an area north of Holyrood known as Duffs along the eastern shore of Conception Bay where there is an exposure of the Holyrood Intrusive Suite and the Harbour Main volcanics   Here's a paragraph from that report.


"Volcanics persist for some 500 m along the shore until they are in intimate intrusive contact with a distinctive pink porphyritic microgranite..."  and "This intrusion is chilled to a pink rhyolitic felsite at the contact...".  


I reacted to the words "intimate" and "chilled", could have been descriptions of a relationship!  And it is, it's a geological relationship.  The wheels in my artist brain are turning...

My plan for the Spring is to get to these three places and maybe climb a little further up the scale into the Conception Group over the summer. Stay tuned…