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 I have abbreviated the content of this page to remove course-specific rubbish and content getting increasingly out of date.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

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