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 I have abbreviated the content of this page to remove course-specific rubbish and content getting increasingly out of date.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

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