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 I have abbreviated the content of this page to remove course-specific rubbish and content getting increasingly out of date.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

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