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 I have abbreviated the content of this page to remove course-specific rubbish and content getting increasingly out of date.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

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