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 I have abbreviated the content of this page to remove course-specific rubbish and content getting increasingly out of date.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

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