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 I have abbreviated the content of this page to remove course-specific rubbish and content getting increasingly out of date.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

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