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 I have abbreviated the content of this page to remove course-specific rubbish and content getting increasingly out of date.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

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