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 I have abbreviated the content of this page to remove course-specific rubbish and content getting increasingly out of date.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

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