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 I have abbreviated the content of this page to remove course-specific rubbish and content getting increasingly out of date.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

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