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 I have abbreviated the content of this page to remove course-specific rubbish and content getting increasingly out of date.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

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