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At least 631 records · Page 35Linked to original sources
USGS2003

Geology of the Right Stepover region between the Rodgers Creek, Healdsburg, and Maacama faults, northern San Francisco Bay region: A contribution to Northern California Geological Society Field Trip Guide, June 6-8, 2003

This Open file report was written as part of a two-day field trip on June 7 and 8, 2003, conducted for the Northern California Geological Society. The first day of this field trip (June 7) was led by McLaughlin and Sarna-Wojcicki in the area of the right- step between the Rodgers Creek- Healdsburg fault zone and the Maacama fault. The second day of the trip (June 8), was led by David Wagner of the California Geological Survey and students having recently completed MS theses at San Jose State University (James Allen) and San Francisco State University (Carrie Randolph-Loar), as well as a student from San Francisco State University whose MS thesis was in progress in June 2003 (Eric Ford). The second day covered the Rodgers Creek fault zone and related faults of the Petaluma Valley area (the Tolay and Petaluma Valley fault zones).

California↗
USGS2007

The contribution of geomagnetic observatories and magnetic models to the study of secular variation and jerks in Antarctica

Some of the most interesting features of the geomagnetic field and its time variations are displayed in polar areas. Observatory monthly means usually provide an excellent opportunity to study the temporal changes of the magnetic field at a given location. Unfortunately, on the Antarctic continent the distribution of the permanent ground- based observatories does not permit a uniform coverage of the examined area. Furthermore, the magnetic records are characterized by intense external disturbances and noise that make the analysis of the magnetic field difficult. To improve our knowledge of the secular variation and detect the presence of secular variation impulses (geomagnetic jerks) in Antarctica, we use both observatory data and the CM4 quiet time magnetic field model. In particular CM4 improves our knowledge of geomagnetic jerks over Antarctica through the study of the sign changes of the secular acceleration maps.

Open-File Report↗
USGS2023

Fall contributions of phosphorus and nitrogen in stormwater runoff through weekly street cleaning

This report describes a study that characterized reductions in total and dissolved forms of phosphorus and nitrogen in stormwater runoff through implementation of a municipal leaf collection and street cleaning program in two medium-density residential catchments in Madison, Wisconsin. One catchment was established as a control in which no effort was made to remove leaf litter and other organic detritus from streets. The second catchment served as the test catchment in which leaf litter was removed through a combination of biweekly leaf collection and weekly mechanical-broom street cleaning. Loads of total and dissolved phosphorus in the test catchment were reduced by 46 and 51 percent (probability less than 0.20), respectively, and total and dissolved nitrogen by 42 and 52 percent (probability less than 0.20), respectively, with an active leaf collection and street cleaning program compared to no program in the control catchment. Results from this study support an ongoing effort to characterize how various combinations of municipal leaf collection and street cleaning can affect nutrient loads in urban runoff.

Wisconsin↗
USGS1954

Contribution to the study of the physico-chemical structure of Clais

The Cormeilles-en-Parisis hill shows one of the best geologic sections of the Paris region. The 80 meter high working face of the quarry exposes the complete section of the "Ludian" [the youngest beds of the Eocene] with its alternations of the marl and gypsum. Above is the sequence of supra-gypseous marls of the [lower oligocene] Sannosian stage, overlain by a very complex series of alternation brackish water and lacustrine layers, from blue marls to Brie limestone, up through the white Pantin marls, brown marls containing the pelecypod genus Cyrena and green marls. These strata overlain by the [Middle Oligocene] Stampian beds represented by the Fontainebleau sands and Ostrea-bearing marls.

Cormeilles-en-Parisis↗
USGS1996

Digital representation of the Washington state geologic map: a contribution to the Interior Columbia River Basin Ecosystem Management Project

This report describes the digital representation of the Washington state geologic map (Hunting and others, 1961). This report contains an explantion of why the data were prepared, a description of the digital data, and information on obtaining the digital files. This report is one in a series of digital maps, data files, and reports generated by the U.S. Geological Survey to provide geologic process and mineral resource information to the Interior Columbia Basin Ecosystem Management Project (ICBEMP). The various digital maps and data files are being used in a geographic information system (GIS)-based ecosystem assessment including an analysis of diverse questions relating to past, present, and future conditions within the general area of the Columbia River Basin east of the Cascade Mountains.

Open-File Report↗