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 I have abbreviated the content of this page to remove course-specific rubbish and content getting increasingly out of date.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

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