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 I have abbreviated the content of this page to remove course-specific rubbish and content getting increasingly out of date.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