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 I have abbreviated the content of this page to remove course-specific rubbish and content getting increasingly out of date.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

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