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 I have abbreviated the content of this page to remove course-specific rubbish and content getting increasingly out of date.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

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