Anticosti Island, located in Eastern Canada, displays one of the most complete, best exposed, and most fossiliferous carbonate successions spanning the Ordovician-Silurian (O/S) Boundary in the World. This study develops a new high-resolution framework for the post End-Ordovician extinction strata (~ 260 m thick) exposed in coastal outcrops and recovered from a continuous drill core (La Loutre #1), both located in the western part of the island. In total, eight facies, all associated with a storm-dominated carbonate system, were recognized and organized into a multi-order depositional cycles. A new high resolution isotopic curve with more than 300 data points from well-preserved bulk micrite samples covers the late Hirnantian to Early Aeronian time interval and corresponds to the upper Ellis Bay, Becscie, Merrimack and lower Gun River formations. Two distinct positive carbon isotope excursions are present in the late Hirnantian part of the Ellis Bay Formation (+5‰) and in the lower Aeronian part of the Gun River Formation (+2‰). These positive isotopic carbon excursions provide a distinctive chemostratigraphic signature for regional and global correlations with other O/S sections. Like the Quaternary δ18O marine signal, our δ18O record is largely coupled with multi-order cyclic facies changes. This study demonstrates the importance of glacio-eustasy following the End-Ordovician glacial maxima as one of the primary factors controlling the stratigraphic architecture of paleotropical neritic carbonates during the Early Silurian.

Rocks of Late Cretaceous age in the central part of Utah are dominantly elastic. In general, the sediments in the west are of conglomerate and sandstone of continental origin; the sediments in the east are of sandstone and shale of marine origin, These rocks were deposited at or near the western shore of a sea which extended from the Arctic to the Gulf of Mexico. The strand line lay in a general northern direction through Utah with land to the west and marine water to the east.

An exhaustive field study of the Cambrian stratigraphy of the northern Wasatch region indicates that in addition to the Blacksmith Fork section there are two complete and better exposed middle and upper sections. Several other good exposures of the lower Middle Cambrian section have been studied in detail. The Spence shale is found to be a member low in the Langston, not the basal member of the Ute. Relative ages of the Spence shale and Ptarmigania faunas have been determined. Other Cambrian faunal zones have been discovered and are discussed. Paleontologic evidence suggests that the Nounan formation is of Upper Cambrian (Cedaria) age. Laboratory and field evidence indicates the probable Lower Cambrian age of the Brigham formation.

Rocks provide insight into ancient times before complex animals existed. The oldest sedimentary rocks in Grand Canyon (the Bass Formation) allow us to glimpse into what things might have been like over a billion years ago. These rocks record the time known as the Mesoproterozoic Era (1.6 to 1.0 billion years ago), otherwise known as the ‘boring billion’. These rocks are thought to be the right age to indicate the end of an oddly stable world when continents were quiet and life was calm, yet they predate younger rocks that record extreme events. The Bass Formation, some of the only rock of this age in the world, contains evidence for life and the carbon cycle, and yields information about Earth’s environments 1.2 billion years ago. The carbon cycle can be studied using carbonate rocks. Assuming that the rock has the same chemistry as the water it formed in, we can measure the relative abundance of carbon isotopes to see a ‘fingerprint’ of the system during the time the rock was deposited. During the boring billion, it is thought that very little variation occurs in this fingerprint. However, as more studies are completed, we see a modest variation in units around the age of the Bass Formation. The fingerprint results from this study can be added to the growing collection of Mesoproterozoic studies and help to further our knowledge about the world from this not-so-boring period of time.

Pacific Northwest ferruginous bauxite deposits have formed in four main areas of northwestern Oregon and southwestern Washington by laterization of flows of the Columbia River Basalt Group (CRBG). The deposits, averaging 36.3% Al2O3 , 31.8% Fe2O3 , and 5.9% Sio2, generally occur near the surface of hilltops in gently rolling areas. Two very different views have been advanced regarding the setting in which the deposits have formed. The first hypothesis calls for a blanket-type laterization by erosion of much of the original deposit upon uplift and dissection of the area.

The Floras Creek area, east of the town of Langlois, near the southwest Oregon coast, includes Colebrooke Schist (a klippe of metamorphosed pelitic sediments of Jurassic age), Jurassic Otter Point Formation (a melange complex), and lower the middle Eocene Roseburg and Lookingglass Formations, part of a sandstone-shale sequence occurring more extensively in other areas. The Colebrooke Schist occurs in the south-central part of the area, bounded on the Otter Point and Roseburg. The Lookingglass is exposed as a small (1.5 sq. km) block in the north-north-west part of the area. Two major structural trends are found in the Floras Creek area; an older Mesozoic east-west normal fault trend which is truncated by younger serpentinitefilled, north-south shear zones. The younger fault trend was active into the Tertiary as the faults cut the Eocene. Detrital modal analyses of sandstones suggest that the Otter Point is related to the coeval Dothan Formation of the interior Klamath Mountains, in the same way that the Franciscan is related to the Great Valley sequence in California. The detrital modal analysis indicates that the Otter Point is trench-slope deposited sediments as is the Franciscan and the Dothan is forearc basin deposits similar to the Great Valley.

Field work in the southeast quarter of the Dutchman ·Butte Quadrangle, which lies within the Klamath Mountains geomorphic province of southwestern Oregon, was completed during the summers of 1973 and 1974. The objectives of the study were fourfold: (1) to produce a geologic map of the southeast quarter of the Dutchman Butte Quadrangle, (2) to determine the nature of the contact between the Dothan and Rogue formations, (3) to construct a stratigraphic column of the Dothan Formation in the area, and (4) to attempt to determine the nature of the deformation occurring in the area.

No description available.

The Tuscaloosa Marine Shale (TMS) in southwest Mississippi and south-central Louisiana has potential to become a prolific source of fossil fuels using hydraulic fracturing technology. The objective of this study is to better understand the sequence and regional stratigraphy, lithology, and character of the TMS. Studying the TMS’s lithologic, depositional, and diagenetic properties is essential to maximize potential production. Characterization of the eastern TMS was performed with cuttings from two wells provided by the Mississippi Oil and Gas Board through MDEQ, and two provided by the USGS. Thirty-one petrophysical logs were correlated, to make cross sections and trace sequence stratigraphic intervals within the TMS. Results of the study showed lithologic variability and compaction across the study area, and a sequence stratigraphic correlation of the highstand systems track between the Tuscaloosa and Eagle Ford Groups. This research aims to work toward the greatest potential of the TMS as an unconventional reservoir.

The Floyd (Neal) Shale is an organic-rich black shale in the Black Warrior Basin that is being explored for its unconventional gas potential. To understand the stratigraphic architecture of the black shale facies in Mississippi, a detailed examination of well logs, conventional core, well log correlation (cross sections) and isopach maps were used to delineate and characterize the Neal Shale depositional facies. From this study it can be concluded that parasequences associated with the upper Pride Mountain Formation, Hartselle, Floyd Shale and Bangor Limestone are equivalent to resistive units in the Neal Shale in Alabama. In Mississippi, the upper Pride Mountain Formation and Hartselle are distinctly separate and the Floyd Shale and Bangor Limestone comprise all equivalent units in the Neal Shale. The Neal Shale reaches maximum thickness of 125 ft and structurally deeper areas with maximum thickness of shale are key areas to focus for future potential gas exploration.