Chris White<p>Now the more <a href="https://sciencemastodon.com/tags/riebeckite" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>riebeckite</span></a> facies of the <a href="https://sciencemastodon.com/tags/Paleozoic" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Paleozoic</span></a> <a href="https://sciencemastodon.com/tags/Quincy" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Quincy</span></a> <a href="https://sciencemastodon.com/tags/Granite" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Granite</span></a></p><p>The Quincy granite was a prized architectural stone, most famously used in the <a href="https://sciencemastodon.com/tags/BunkerHill" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>BunkerHill</span></a> Monument in <a href="https://sciencemastodon.com/tags/Boston" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Boston</span></a> <a href="https://sciencemastodon.com/tags/Massachusetts" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Massachusetts</span></a>. Current dating suggests it was intruded into <a href="https://sciencemastodon.com/tags/Avalonia" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Avalonia</span></a> before it glommed onto <a href="https://sciencemastodon.com/tags/Laurentia" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Laurentia</span></a> as <a href="https://sciencemastodon.com/tags/Laurasia" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Laurasia</span></a> and <a href="https://sciencemastodon.com/tags/Pangea" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Pangea</span></a> were assembled. Today’s <a href="https://sciencemastodon.com/tags/photo" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>photo</span></a> set comes from a walk around the eponymous Bunker Hill Quarry. I’ll post more about the history later. Captions!<br><a href="https://sciencemastodon.com/tags/Fujifilm" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Fujifilm</span></a> <a href="https://sciencemastodon.com/tags/XH1" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>XH1</span></a> <a href="https://sciencemastodon.com/tags/igneous" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>igneous</span></a> <a href="https://sciencemastodon.com/tags/intrusive" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>intrusive</span></a> <a href="https://sciencemastodon.com/tags/NewEngland" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>NewEngland</span></a></p>
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Chris White<p>Quincy or <a href="https://sciencemastodon.com/tags/BlueHills" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>BlueHills</span></a> <a href="https://sciencemastodon.com/tags/Porphyry" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Porphyry</span></a> <a href="https://sciencemastodon.com/tags/Granite" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Granite</span></a><br>An alkaline, nonorogenic granite intruded into <a href="https://sciencemastodon.com/tags/Avalonia" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Avalonia</span></a> in the <a href="https://sciencemastodon.com/tags/Silurian" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Silurian</span></a> / <a href="https://sciencemastodon.com/tags/Ordovician" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Ordovician</span></a> as it cruised from peri-<a href="https://sciencemastodon.com/tags/Gondwana" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Gondwana</span></a> to <a href="https://sciencemastodon.com/tags/Laurentia" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Laurentia</span></a>, before assembling <a href="https://sciencemastodon.com/tags/Pangea" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Pangea</span></a> in the <a href="https://sciencemastodon.com/tags/Acadian" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Acadian</span></a> <a href="https://sciencemastodon.com/tags/Orogeny" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Orogeny</span></a> (<a href="https://sciencemastodon.com/tags/Devonian" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Devonian</span></a>). It’s coarse, with the <a href="https://sciencemastodon.com/tags/phenocrysts" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>phenocrysts</span></a> of amphiboles(?) (possibly riebeckite?)…I’m no petrologist. From@the Eaton’s Pond conservation area@at the <a href="https://sciencemastodon.com/tags/Braintree" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Braintree</span></a> <a href="https://sciencemastodon.com/tags/Quincy" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Quincy</span></a> border. My photos.<br><a href="https://sciencemastodon.com/tags/geology" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>geology</span></a> <a href="https://sciencemastodon.com/tags/igneous" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>igneous</span></a> <a href="https://sciencemastodon.com/tags/Massachusetts" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Massachusetts</span></a> <a href="https://sciencemastodon.com/tags/Boston" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Boston</span></a> <a href="https://sciencemastodon.com/tags/NewEngland" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>NewEngland</span></a> <a href="https://sciencemastodon.com/tags/Fujifilm" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Fujifilm</span></a> <a href="https://sciencemastodon.com/tags/photo" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>photo</span></a></p>
Vicky Veritas<p>Wilson Cycle Phase 3: Ocean Closing</p><p>“I enjoy, and have always enjoyed, disturbing scientists.”</p><p>~ John Tuzo Wilson</p><p>“From great oceans, giant mountains will form. This is the prediction of the third phase of the Wilson Cycle where we see the closure of the vast oceans like the Iapetus Ocean, and the formation of continent to continent collision mountains.”</p><p>~ Professor Dougal Jerrom, intro to Wilson Cycle Phase 3: Ocean Closing video linked below</p><p>In the 24 minute video below (a great watch), we continue our travels with Professor Dougal Jerrom of Oslo University, to look at evidence of the closing of the former Iapetus Sea in the Caledonian of Norway. The video starts with a nice recap of the other videos.</p><p>Whenever there is an ocean closure, geoscientists always look for ophiolite. Ophiolites in the geologic record provide evidence of subduction zone tectonics. We have already seen the pillow basalts, sheeted dikes (gabbros) and peridotites that form ocean crust in earlier videos in this series. An ophiolite is then a bit of oceanic crust that got swept up in the continental collisions and provides the first proof of an ocean closure.</p><p>Next we learn about melange - the sediments that were scraped up during subduction, also known as an accretionary wedge. There are also remnants of the island arc formed during subdution all accreted between the bits of continental crustal blocks that eventually collided.</p><p>Enjoy the video below where you see glimpses of the geology of the beautiful Norwegian Caledonian.</p><p>Wilson Cycle Phase 3: Ocean Closing: <a href="https://youtu.be/jYlQCbDmEVw" rel="nofollow noopener" target="_blank"><span class="invisible">https://</span><span class="">youtu.be/jYlQCbDmEVw</span><span class="invisible"></span></a></p><p>More on the closing of the Iapetus Sea here: <a href="https://en.m.wikipedia.org/wiki/Iapetus_Ocean" rel="nofollow noopener" target="_blank"><span class="invisible">https://</span><span class="ellipsis">en.m.wikipedia.org/wiki/Iapetu</span><span class="invisible">s_Ocean</span></a></p><p>Includes Step 5 of the Wilson Cycle: <a href="https://c.im/@vickyveritas/10962360456" rel="nofollow noopener" target="_blank"><span class="invisible">https://</span><span class="">c.im/@vickyveritas/10962360456</span><span class="invisible"></span></a>...</p><p>Refer to this great labeled diagram of the Wilson Cycle for the components of the ocean closure and continent to continent collision and mountain building: <a href="https://c.im/@vickyveritas/109628513962823739" rel="nofollow noopener" target="_blank"><span class="invisible">https://</span><span class="ellipsis">c.im/@vickyveritas/10962851396</span><span class="invisible">2823739</span></a>
<br>Note: We will see the last steps of the Wilson Cycle, the continent to continent collision and the formation of giant mountain belts, and the great grand finale of this series. Stay tuned.<br>
<a href="https://c.im/tags/JohnTuzoWilson" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>JohnTuzoWilson</span></a> <a href="https://c.im/tags/TheWilsonCycle" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>TheWilsonCycle</span></a> <a href="https://c.im/tags/Caledonides" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Caledonides</span></a> <a href="https://c.im/tags/IapetusOcean" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>IapetusOcean</span></a> <a href="https://c.im/tags/Norway" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Norway</span></a> <a href="https://c.im/tags/PlateTectonics" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>PlateTectonics</span></a> <a href="https://c.im/tags/Ophiolite" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Ophiolite</span></a> <a href="https://c.im/tags/AccretionaryWedge" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>AccretionaryWedge</span></a> <a href="https://c.im/tags/granites" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>granites</span></a> <a href="https://c.im/tags/SutureZones" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>SutureZones</span></a> <a href="https://c.im/tags/Laurentia" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Laurentia</span></a> <a href="https://c.im/tags/Baltica" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>Baltica</span></a> <a href="https://c.im/tags/geology" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>geology</span></a> <a href="https://c.im/tags/ScienceMastodon" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>ScienceMastodon</span></a> <a href="https://c.im/tags/NorwegianGeologyRocks" class="mention hashtag" rel="nofollow noopener" target="_blank">#<span>NorwegianGeologyRocks</span></a> @geology</p>
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