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 I have abbreviated the content of this page to remove course-specific rubbish and content getting increasingly out of date.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

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