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 I have abbreviated the content of this page to remove course-specific rubbish and content getting increasingly out of date.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

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