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 I have abbreviated the content of this page to remove course-specific rubbish and content getting increasingly out of date.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

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