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 I have abbreviated the content of this page to remove course-specific rubbish and content getting increasingly out of date.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

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