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 I have abbreviated the content of this page to remove course-specific rubbish and content getting increasingly out of date.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

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