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 I have abbreviated the content of this page to remove course-specific rubbish and content getting increasingly out of date.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

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