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 I have abbreviated the content of this page to remove course-specific rubbish and content getting increasingly out of date.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

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