Early Proterozoic Geology of the Highland Mountains, Southwestern Montana, and Field Guide to the Basement Rocks that Compose the Highland Mountain Gneiss Dome part of MT Field Guides
The Highland Mountains are underlain by the largest of the northwesternmost exposures of basement crystalline rocks in southwestern Montana....Metasedimentary rocks in the Highland Mountains are in part lithologically similar to the Late Archean multilithologic sequence (in the Tobacco Root, Ruby, and the northern Madison and Gravelly Ranges), but are considerably thinner. In the Highland Mountains the individual beds of aluminous schist, marble, quartzite, and iron-formation extend for only short distances, but the assemblage as a whole is mappable. It nowhere exceeds 300 ft (100 m) in thickness and appears to pinch out to the north....these rocks in the Highlands, unlike those to the southeast, are overlain by more than 10,000 ft (3000 m) of aluminous biotite gneiss that may have been deposited as muds basinward from the Late Archean shelf edge.

Middle Proterozoic Belt Supergroup, Western Montana part of MT Field Guides
From Great Falls, to Butte, Helena Glacier National Park and Spokane, this field trip crosses onto the leading edge of the Rocky Mountain thrust belt and proceeds to the stratiform copper-silver deposits in the Revett Formation of the Troy Mine in the main part of the Belt basin. The road log includes sections on the paleontology of the Middle Proterozoic Belt Supergroup, stromatolites of the Belt Supergroup (specific to Glacier National Park), Middle Proterozoic Tectonics of the Belt basin, and a sedimentologic and tectonic interpretation of the Belt Supergroup.

Field Guide; Little Rocky Mountains part of MT Field Guides
This fieldtrip examines deformed Paleozoic sedimentary rocks on the margins of the Little Rocky Mountains, Tertiary intrusive rocks (porphyrys, magmatic-hydrothermal breccias, and dikes), and associated mineralization.

Crazy Mountains, Montana part of MT Field Guides
This trip examines a variety of mid-Eocene alkalic (feldspathoidal) stocks, laccoliths, sills, and dikes emplaced into Cretaceous and Paleozoic sedimentary strata. These rocks include mafic and felsic varieties, and are both texturally and compositionally variable. Most of the mafic alkalic rocks are unique in the Montana Alkalic Province in having Na2O > K2O. They are unusual even among feldspathoidal rocks because they are stongly enriched in incompatible elements, and have Sr, Nd, and Pb isotopic compositions which reflect an ancient source having low Rb/Sr, Sm/Nd, and U/Pb.

Geology of the Butte Mining District part of MT Field Guides
The Butte mining district is one of the major mining districts of the world with continuous production from both underground and open pit mines for 119 years, from 1864 to 1983. During this time, mining activites at Butte have introduced many firsts in mining methods, techniques of mine mapping, and the detailed recording of geologic data. This field guide describes the geology of the mineral deposits, provides a geologic map of the district, and concludes with a tour of eight locations of interest, including Alice pit, Syndicate pit, Berkeley pit, the Emma and Orphan Boy veins of the Anaconda system, the World Museum of Mining, and the Montana Tech Mineral Museum.

Shonkin Sag and Square Butte Laccoliths, Montana part of MT Field Guides
Shonkin Sag and Square Butte laccoliths are at the eastern edge of the Highwood Mountains as part of the Central Montana Alkalic Province. Rocks in the Highwood Mountains date to 50-53 Ma. Both laccoliths are internally differentiated and contain a variety of rock types, including shonkinite, syenite, and pegmatite.

The Stillwater Complex, Southern Montana; A Layered Mafic Intrusion part of MT Field Guides
Layered complexes provide the most visible evidence of processes of magmatic differentiation; thus, they occupy a central place in the study of igneous petrology. Such complexes are not only scientifically rewarding, they are host to several types of mineral deposits, including copper-nickel, chromium, and platinum-group elements. The Stillwater Complex is one of the world's great layered mafic intrusions, distinguished not so much by its size as by the fact that it is tilted on its side, and erosion has exposed the layering to ready access. This fieldguide presents a summary of the geology of the complex in the Benbow and Mountain View areas. The Benbow area offers easy access to a variety of rocks from the ultramafic series and chromite deposits but only limited exposures of features from the banded series. The Mountain View area offers easy access to most of the banded series and the platinum deposits.

Road Log to the Picket Pin Mountain, Chrome Mountain and Contact Mountain Areas part of MT Field Guides
This road log describes the geologic features along the access roads for three additional traverses: Guide to the Picket Pin Mountain Area, Guide to the Chrome Mountain Area, and A Traverse Through the Banded Series in the Contact Mountain Area. "This trip requires nearly 2 hours without stops. Beyond 12.5 miles, the road is rough and steep in places; a four-wheel-drive vehicle is recommended.

Yellowstone and Grand Teton National Parks and the Middle Rocky Mountains part of MT Field Guides
This trip is designed to show participants the granite-cored Laramide (Late Cretaceous-earliest Eocene) mountain ranges in the middle Rocky Mountains, and their various stages of burial by Cenozoic deposits and subsequent Quaternary exhumation. Mountain-flank structures involving Precambrian, Paleozoic, and Mesozoic rocks, the classic Heart Mountain detachment fault complex, and the rootless overthrust mountain ranges of the Wyoming-Utah-Idaho thrust belt are traversed.

A Traverse Through the Banded Series in the Contact Mountain Area part of MT Field Guides
This traverse through the Banded Series of the Stillwater Complex follows the section described in detail by McCallum and others (1980)....Unusual or particularly interesting features are highlighted by the 22 localities along the traverse. In view of the nearly continuous outcrop, however, there is much of interest to see between localities, and full appreciation of the entire section would require several days. Nonetheless, most of the important rock types can be seen on a 1-day trip.