Petrology, GEO-320 – Kurt Hollocher

I have retired, and so this course is no longer taught by me. I have abbreviated the content of this page to remove course-specific rubbish and content getting increasingly out of date. If you find any of the things here useful, that’s good.

Special documents	Syllabus
	Using petrographic microscopes: adjustments and features
	Thin section collections
Igneous rock labs	White Mountain magma series	WMMS photo gallery
	New Hampshire magma series	NHMS photo gallery
	Skaergaard and Stillwater intrusions	Skaergaard photo gallery, Stillwater photo gallery
	Iceland lavas	Iceland photo gallery
Metamorphic rock labs	New England schists	New England geology 1, 2; metamorphism 1, 2 Photo gallery
	New England mafic rocks	New England geology 1, 2; metamorphism 1, 2 Photo gallery
	Norwegian eclogites	Fennoscandia geologic map, very simplified map Photo gallery
	Fault rocks	Fault rocks photo gallery
Forms and graph paper	Rock report form Ternary graph paper, and a green one
Theriak-Domino help	Theriak-Domino tips, tricks, and tools Introductory Theriak-Domino exercise I used in this course (pdf) R program to put together all those pixelmaps files (txt)
Documents and spreadsheet utilities	Writing igneous rock hand sample descriptions Writing metamorphic rock hand sample descriptions Making thin sections at Union College Why petrology is so much fun
	Calculate Fe3+ values for amphibole probe analyses Calculate Fe3+ values for biotite probe analyses Fill in missing values on REE diagrams! Make ternary (triangle) diagrams in spreadsheets! Whole rock geochemical discriminant diagrams! Norm calculation spreadsheet for single samples (a macro-enabled version for many samples is available but can't be loaded onto this system, so contact me for a copy)
Image libraries	Igneous minerals in thin section Igneous textures in thin section Metamorphic minerals in thin section Metamorphic reactions in thin section Metamorphic microstructures in thin section Moon rocks Hand sketches in petrology

SVG vector graphics files for figures I use in this course (native Inkscape).

Assorted field trip images

Intrusion breccias and other intrusive features in the roots of the Taconic island arc, Shelburn Falls, Massachusetts.
Rainwater pool off the main trail, looking southeast toward Bald Rock.
Sarah, done with her sandwich. Not sure if it was the finest.
Late quartz vein with 25 cm wide tourmalinized zone around the vein.
Looking at metamorphosed quartz pebble conglomerate in the Cheshire Quartzite, Pine Cobble Trail, Williamstown, MA.
Natural Bridge, in Natural Bridge State Park, North Adams, MA.
Deformed xenolith breccia in gabbroic rocks, as part of the older plutonic complex in the roots of the Taconian island arc. Shelburne Falls.
A new friend.
Infold of marble and calc-silicate layers into a partially separated amphibolite boudin neck, banks of the Hudson River.
Large twinned plagioclase, summit of Mt. Jo, in an anorthosite block within the leuconorite.
Normal-size samples are sufficient for normal people.
Magnetite ore body and mine west of Ticonderoga, NY.
Contact between a granitic gneiss (light colored center and right) and a garnet amphibolite (lower left).
Coticule layer near the Billings Fold.
Brian pops out of the boulder cave.
Large tourmaline crystals in a quartz vein. Longest crystal is ~4 cm.
Eroded lamprophyre dike, near the summit of Mt. Jo.
Off the trail looking at complex isoclinal folds and graded quartzite beds.
David pops out of the boulder cave.
Large xenolith choking the interior of a thin tourmaline granite sill.
The whole hiking crew.
Samples of magnetite-garnet sand, Schroon River.
Sarah and Sarah walking up to Bald Rock.
Looking at a quartz-pebble conglomerate in the Cheshire Quartzite, about half way up the trail to Pine Cobble, Williamstown.
Looking at a thin ferrogabbro dike crosscutting anorthosite.
Another group photo at Pine Cobble, Williamstown, Massachusetts. Stop 4 at 9:00 AM. Photo donated by Ralf Schauer.
Graded quartzite bed, stratigraphic top to the upper right.
On the hike down we found another part of the Billings Fold, ~200 m along the axial surface.
Metamorphosed Cambro-Ordovician volcaniclastic sediments on the east side of the Berkshires. Abundant quartz veins and glacial striations.
Feeling for fault movement indicators on a slickensided surface, Waloomsac Formation, Rt. 8, North Adams, Massachusetts.
Group photo from Pine Cobble, Williamstown, Massachusetts. Stop 4 at 9:00 AM.
Layer truncations against a thick quartzite. Possible pre-metamorphic sedimentary structures, or a fault surface.
Nick eating the finest peanut butter sandwich in New Hampshire.
Folded quartzite beds.
Boulder cave exit.
Blue calcite!
Black Precipice for lunch.
Tonalitic gneisses and amphibolites at the Shelburne Falls, Shelburne Falls, Massachusetts.
More folded quartzite beds. Wind is gusting to 50 mph.
Petrology, 2000. Sarah, Nick, Mike, Bill, Sarah, Jeremy on the summit.
Metamorphosed limestone of the West Stockbridge Formation, North Adams, Massachusetts.
Chicken track pattern of andalumps on a foliation surface.
Looking down on Heart Lake, adjacent to the Adirondack Loj campground.
Highly deformed marble on the shores of the Hudson River.
Pre-hike lunch making. Nothing better than peanut butter and jelly!
View to the east from the summit. Boston was not visible today.
The “Billings Fold”, a large isoclinal syncline just below and southwest of the Monadnock summit.
Hornblende needles in muscovite-biotite-chlorite-garnet schist.
Same as above, with Mike and Bill for scale.
More lunch on Black Precipice.
Summit of Monadnock.
Silurian Clough quartzite, Crag Mountain, just west of the Connecticut River valley.
Part of the class.
Big garnet outcrop, Warrensburg, NY.
Large plagioclase megacryst in anorthosite, Mt. Jo.
Small fault with calcite infilling, cutting calc-silicate block in marble, Paradox.
Large plagioclase crystal in Mt. Marcy-type anorthosite, Mt. Jo, short trail up.
Isoclinally folded quartzite beds.
The two notches in the outcrop are weathered out alkali basalt (camptonite?) dikes cutting leuconorite, near the summit of Mt. Jo.
Labradorite showing labradorescence. It is caused by a diffraction effect from closely-spaced exsolution lamellae.
Jeremy on Littleton Schist, with large sillimanite pseudomorphs after andalusite on the rock surface to the right.
Trying to get out to the outcrop in the middle of the river, Jay.
Crossing Roaring Brook on the way to some outcrops, Giant Mountain, Adirondacks.
Halfway house site, with andalump schist and pegmatite.
Exposures of the Roaring Brook intrusion breccia, Giant Mountain, Adirondacks.
Coming down from the summit. It’s actually not as steep as it looks.
Lunch on Black Precipice. Garnet- and tourmaline-bearing granite dikes and sills visible in the schist.
Alkali basalt dike cutting leuconorite, on the long trail down from the summit of Mt. Jo.
“Billings Fold” just below the summit.
Summit of Monadnock.
More isoclinally folded quartzite beds.
Late fault offsetting quartzite layer.
And snacks, too!
Nick and Bill hanging out.
Boulder cave entrance.
Metamorphosed tonalitic intrusives of the Taconian arc complex, Shelburne Falls, MA.
Mylonite zone cutting gabbroic anorthosite, Keene Valley.
Looking at leuconorite, cut by numerous ferrosyenite dikes that form an extremely block-rich intrusion breccia.
Hornblende-diopside-plagioclase-calcite vein in an amphibolite ‘xenolith’ in the deformed marble, banks of the Hudson River.
Looking back from the location above to the Billings Fold itself.
Well, it beats PB and J again.
Largest plagioclase megacryst in anorthosite, Mt. Jo.
Folded marble, West Stockbridge Formation, Natural Bridge Park, North Adams, Massachusetts. Photo donated by Ralf Schauer.
Praying for divine guidance: what is that soft, flakey, metallic mineral in this marble?
The Fairy at Fairy Spring, on the Fairy Spring trail to Monta Rosa.
Looking at metamorphosed quartz pebble conglomerate in the Cheshire Quartzite, Pine Cobble Trail, Williamstown, MA.
Charnockite gneiss near Schroon Lake.
Summit of Monta Rosa, with tourmaline veins, garnets, andalumps, and sillimanite fibers.
Anna pops out of the boulder cave.
Early risers in Petrology, 2004.
Looking at Clough Quartzite, Cragg Mountain trail, Northfield, MA.
Lunch on Black Precipice, sitting on the “Seven Sisters” quartzite beds.
Checking out an especially large muscovite crystal in a pegmatite dike.
Off the main trail, looking toward the summit.
Boulder cave exit, again.
Portrait of an unhappy snake.
Patrick pops out of the boulder cave.
Cambrian Cheshire quartzite on Pine Cobble, Williamstown, Massachusetts.
Outcrop of Clough Quartzite on Crag Mountain, Erving, Massachusetts. View to south-southeast toward the Northfield Mountain pumped storage reservoir in the Pelham Dome.
Metamorphosed tonalitic intrusives of the Taconian arc complex, Shelburne Falls, MA.
The true breakfast, lunch, and dinner of champions.
Nice red garnets. The schists contain red garnets up to 2 cm across.
Searching for blue calcite, cascade slide.
Deformed marble with numerous ‘xenolith’ blocks and folded layers, Paradox.
Paying homage to partially recrystallized (Whiteface Mtn. type) anorthosite.
Approaching the summit region.
Large plagioclase crystal in a block of anorthosite within the leuconorite, summit of Mt. Jo.
“Billings Fold” near the Monadnock summit.
Bill reading the paper.
Eroded lamprophyre dike, near the summit of Mt. Jo.
View to the southwest, overlooking Monta Rosa.
Bill, hanging up.
Summit of Monadnock.
Salamander escapes from tent caterpillar.
Looking closely at the corona textures and the green plagioclase flow foliation in a corona gabbro, near Schroon Lake.
Summit of Mt. Jo.
Large quartz mass in the neck between two large amphibolite boudins in marble, Paradox.
Large metamorphic garnets in an amphibolite.
Even more lunch.
Coarse-grained, intensely folded graphite- and diopside-bearing marble on the shores of the Hudson River, Warrensburg, NY.
View from the summit to the south, toward Bald Rock (left) and the halfway house site (right).
Snoozing on the flysch and chips outcrop, eastern Berkshires, Massachusetts.
Coarse-grained marble on the shores of the Hudson River.
End of the trip on the summit of Crag Mountain, on Silurian Clough quartzite which is made out of deformed quartz pebbles and cobbles.
If you are going to take a snooze, it might as well be in a nice spot!
Looking back toward the summit from Bald Rock, on the way to the graphite mine and the boulder cave.
Lunch on Black Precipice, looking south at the landscape.
Large tourmaline crystals in a quartz vein. Largest crystal is ~5 cm long.
Ferrosyentie dike cutting leuconorite, summit of Mt. Jo.
Folded calc-silicate layer in marble, banks of the Hudson River.
Nice graded quartzite bed. Top is to the upper left.
Group photo on Crag Mountain, Erving, Massachusetts, view to northeast.
Marble-matrix breccia near Paradox.
Reaching the top of Mt. Jo, high peaks in the distance.
Large garnets in melt pockets in an amphibolite.
Searching for mega-samples, as usual.
Looking southwest from the top of Roaring Brook falls, Giant Mountain, Adirondacks.
Graded quartzite beds in Littleton Formation schist. Person is standing on the axial surface of an isoclinal fold that repeats the bed, upside down in front and right side up behind.
Fold hinge in one of the isoclinally folded quartzite beds.
The largest plagioclase crystal found in this trip, larger than a size 12 boot.
Looking for graphite in marble, Warrensburg, NY.
Woodchuck on Jurassic red bed sediments, Turners Falls, MA.
Large sillimanite pseudomorph after andalusite, ~35 cm long.
Eroded lamprophyre dike, near the summit of Mt. Jo.
Summit of Mt. Jo.
Walloomsac metamorphosed calcareous sandstone, Rt. 8, North Adams, MA.
Salamander rushes off at top speed.
Summit of Mt. Jo.