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 I have abbreviated the content of this page to remove course-specific rubbish and content getting increasingly out of date.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

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