Identification_Information: Citation: Citation_Information: Originator: Joel E. Robinson Originator: Wes Hildreth Originator: Judy Fierstein Publication_Date: 20160713 Title: Database for the eruptive history of Mammoth Mountain and its mafic periphery, California Geospatial_Data_Presentation_Form: vector digital data Series_Information: Series_Name: Professional Paper Issue_Identification: PP 1812 Publication_Information: Publication_Place: Reston, VA Publisher: U.S. Geological Survey Online_Linkage: https://pubs.er.usgs.gov/publication/pp1812 Larger_Work_Citation: Citation_Information: Originator: Judy Fierstein Originator: Wes Hildreth Publication_Date: 20160713 Title: Eruptive History of Mammoth Mountain and its Mafic Periphery, California Geospatial_Data_Presentation_Form: map Series_Information: Series_Name: Professional Paper Issue_Identification: PP 1812 Publication_Information: Publication_Place: Reston, VA Publisher: U.S. Geological Survey Online_Linkage: https://pubs.er.usgs.gov/publication/pp1812 Description: Abstract: The metadata file was written to provide an overview for the database describing trachydacite complex of Mammoth Mountain and an array of contemporaneous mafic volcanoes in its periphery together form a discrete magmatic system that is thermally and compositionally independent of the adjacent subalkaline Long Valley system (Hildreth, 2004). The Mammoth system first erupted about 230 ka, last erupted about 8 ka, and remains restless and potentially active. Magmas of the Mammoth system extruded through Mesozoic plutonic rocks of the Sierra Nevada composite batholith as well as through extensive remnants of pre-batholithic metasedimentary wall rocks and synbatholithic metavolcanic rocks (Bailey, 1989, 2004). All of the many mafic and silicic vents of the Mammoth system are west or southwest of the concealed structural boundary of Long Valley caldera; none lie inboard of the caldera's buried ring-fault zone, and only one Mammoth-related vent appears to lie within that zone. Mammoth Mountain has sometimes been called part of the Mono-Inyo volcanic chain, but we regard that assignment inappropriate and misleading. Although the rhyolitic Inyo alignment (which is directed by the rangefront fault system) trends toward Mammoth Mountain, the basalt-to-dacite Mammoth vent array is scattered, nonlinear, far broader, and much older. The 10- x 20-km footprint of the Mammoth vent array essentially ignores existence of Long Valley caldera and the Mono-Inyo alignment. Moreover, the Mammoth Mountain dacite dome complex ended its period of eruptive activity (11350 ka) well before the principal Holocene interval of Mono-Inyo rhyolitic volcanism. Here we describe 63 map units that compose the Mammoth basalt-to-rhyodacite system, along with numerous other rock units that crop out within the map area including 8 rhyolitic units of the Long Valley system, 4 units of the Holocene Inyo Chain, and 32 Tertiary volcanic units. Of the 63 Mammoth units, 17 are phenocryst-rich trachydacite lavas of the main edifice, two are similar trachydacite lava domes (units d61 and d81) that erupted at vents just north of the edifice, and 6 are edifice-based alkalic rhyodacites that carry fewer phenocrysts. Units of the Mammoth system peripheral to the edifice include 13 basalts, 16 mafic andesites, 6 silicic andesites, and 3 distinctively different dacites. Usually we prefer to keep volcanic-rock nomenclature simple by basing it entirely on SiO2 contents: basalt has 47-52% SiO2, basaltic andesite 52-57%, andesite 57-63%, dacite 63-68%, rhyodacite 68-72%, and rhyolite more than 72% SiO2. Because the Mammoth suite straddles the alkaline/subalkaline boundary of LeBas and others (1986), however, we largely adopt their nomenclature in the unit descriptions below. Of the basaltic units, some are subalkaline basalts and others are trachybasalts; all more silicic units of the Mammoth suite are alkalinebasaltic trachyandesites, trachyandesites, and trachydacites. Because the six most evolved map units erupted at the Mammoth Mountain edifice have fewer phenocrysts and higher silica contents (70-71%) than the volumetricaly dominant trachydacites (63-69% SiO2), we distinguish them as alkalic rhyodacites. Rhyolites of the Long Valley system are subalkaline, and products of the Inyo chain are complex hybrids. In the unit descriptions, we abbreviate names of the common volcanic phenocrysts clinopyroxene and orthopyroxene as cpx and opx, respectively. Phenocrysts are defined here as 0.5 mm and larger; microphenocrysts (mph) as 0.1 to 0.4 mm; and microlites smaller still. The modifier phenocryst-rich means that a rock has greater than or equal to 12% crystals larger than 0.4 mm; phenocryst-poor signifies less than or equal to 5%; aphyric means what it says none. Rocks containing 6 to 12% phenocrysts we typically characterize as moderately porphyritic or of moderate phenocryst content. Because crystal sizes range widely for each species within most thin sections (and more so within map units), we give estimates of combined abundance of phenocrysts and microphenocrysts for each species in each unit, followed parenthetically by the size range measured in thin section for each from microphenocrysts (>0.1 mm) to the largest crystal observed. [For example, 7-10% plagioclase (mph to 4 mm); 23% olivine (mph to 1.5 mm); and sparse Fe-Ti-oxide mph]. Antecrysts are cognate crystals out of equilibrium with their current igneous host but inferred to have been inherited from an earlier stage of the same (thermally or compositionally) evolving magma system. Xenocrysts are crystals foreign to the system. Most of the volcanic map units described here are newly defined, although equivalents of several were defined by Bailey (1989). Each is an eruptive unit derived from a single vent or dike-fed alignment of vents. Some are simple flow units, but many consist of scoria cones and one or several lava flows that have chemical and mineralogical coherence. Most units of the Mammoth Mountain edifice are lava domes, some of which also issued thick coulees 12 km long. Each map unit was delineated by field mapping on foot and its integrity confirmed, challenged, or revised by chemical, paleomagnetic, and microscopic work in the laboratory. Definition of a few units required iterative acquisition of field and lab data over a period of years, providing a firm basis for subdividing, lumping, or correlating somewhat heterogeneous packages of lavas. Most units have narrow compositional ranges, but some show zoning or heterogeneity spanning ranges of a few percent SiO2. SiO2 contents reported in the description of each volcanic unit are based on major-element analyses normalized on an anhydrous basis, determined by x-ray fluorescence methods in the U.S. Geological Survey laboratory at Lakewood, Colorado, supervised by J.E. Taggart, or in the Washington State University GeoAnalytical Laboratory, supervised by J.A. Wolff and R.M. Conrey. Purpose: This database was constructed in order to produce a geologic map as a basis for understanding volcanic and geothermal processes involved in the creation of the Mammoth Mountain and its mafic periphery. Supplemental_Information: This database contains geodatabase feature classes describing geologic lines and polygons, faults, caldera boundaries, and rock chemistry, and a raster of the topographic base. This metadata file provides an overview for all of these files. For more detailed metadata, please see the metadata provided with each individual geodatabase file. Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 20160713 Currentness_Reference: publication date Status: Progress: Complete Maintenance_and_Update_Frequency: None planned Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -119.135726 East_Bounding_Coordinate: -118.741213 North_Bounding_Coordinate: 37.881170 South_Bounding_Coordinate: 37.533402 Keywords: Theme: Theme_Keyword_Thesaurus: None Theme_Keyword: Dacite Theme_Keyword: debris avalanche Theme_Keyword: Rhyodacite Theme_Keyword: lava flows Theme_Keyword: Basaltic andesite Theme_Keyword: Basalt Theme_Keyword: Caldera Theme_Keyword: Andesite Theme_Keyword: Mammoth Mountain Theme_Keyword: Rhyolite Theme: Theme_Keyword_Thesaurus: ISO 19115 Topic Categories Theme_Keyword: inlandWaters Place: Place_Keyword_Thesaurus: None Place_Keyword: Mammoth Lakes Place_Keyword: United States of America Place_Keyword: California Place_Keyword: Long Valley Caldera Place_Keyword: Mammoth Mountain Temporal: Temporal_Keyword_Thesaurus: None Temporal_Keyword: Pleistocene Temporal_Keyword: Holocene Temporal_Keyword: Quaternary Access_Constraints: None Use_Constraints: Uses of this digital geologic map should not violate the spatial resolution of the data. Although the digital form of the data removes the constraint imposed by the scale of a paper map, the detail and accuracy inherent in map scale are also present in the digital data. The data was edited at a scale of 1:24,000 and higher resolution information is not present in the dataset. Plotting at scales larger than 1:24,000 will not yield greater real detail, although it may reveal fine-scale irregularities below the intended resolution of the database. Similarly, where this database is used in combination with other data of higher resolution, the resolution of the combined output will be limited by the lower resolution of these data. Acknowledgment of the U.S. Geological Survey would be appreciated in products derived from these data. Point_of_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Person: Joel E. Robinson Contact_Position: Geologist Contact_Address: Address_Type: mailing Address: MS 910 Address: 345 Middlefield Road City: Menlo Park State_or_Province: CA Postal_Code: 94025 Country: US Contact_Voice_Telephone: 650-329-5322 Contact_Facsimile_Telephone: 650-329-5203 Contact_Electronic_Mail_Address: jrobins@usgs.gov Contact_Instructions: Please contact via e-mail Data_Set_Credit: Geology mapped by W. Hildreth and J. Fierstein (2004-2012) Native_Data_Set_Environment: Microsoft Windows Server 2008 R2 Version 6.1 (Build 7601) Service Pack 1; Esri ArcGIS 10.2.0.3348 Data_Quality_Information: Logical_Consistency_Report: Polygon and arc (chain-node) topology present in appropriate feature classes. Other feature classes are point, annotation or raster and do not require topologic relationships. Completeness_Report: The report is intended to describe completely the igneous and volcanic products, and volcanic vent locations at 1:24,000 scale. Geological information appropriately mapped at larger scale has been omitted. Positional_Accuracy: Horizontal_Positional_Accuracy: Horizontal_Positional_Accuracy_Report: The position of each feature in the database is derived from a USGS 1:24,000 topographic base map or with a GPS. The positional accuracy of each feature is indicated quantitatively within the LocationConfidenceMeters field in the attribute table. In general, featueres in the database are well located. Vertical_Positional_Accuracy: Vertical_Positional_Accuracy_Report: No vertical positional data recorded Lineage: Process_Step: Process_Description: Geologgy was compiled on USGS 1:24,000-scale topographic maps (or fieldsheets) by Wes Hildreth and Judy Fierstein. Joel Robinson scanned the fieldsheets at 400 dpi, and georeferenced the scans. He converted the linework to vector data using heads-up-digitizing. Polygon topology was created and each arc and polygon tagged on-screen by Joel Robinson and Judy Fierstein. Points features were also then added from the scanned feildsheets through head-up-digitizing. The digitized geology was then combined with topography and plotted to be checked by the authors. Process_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Person: Joel E. Robinson Contact_Position: Geologist Contact_Voice_Telephone: 650-329-5322 Contact_Facsimile_Telephone: 650-329-5203 Contact_Electronic_Mail_Address: jrobins@usgs.gov Contact_Instructions: Please contact via e-mail Spatial_Data_Organization_Information: Direct_Spatial_Reference_Method: Vector Point_and_Vector_Object_Information: SDTS_Terms_Description: SDTS_Point_and_Vector_Object_Type: GT-polygon composed of chains Point_and_Vector_Object_Count: 833 SDTS_Terms_Description: SDTS_Point_and_Vector_Object_Type: GT-polygon composed of chains Point_and_Vector_Object_Count: 688 SDTS_Terms_Description: SDTS_Point_and_Vector_Object_Type: Entity point Point_and_Vector_Object_Count: 45 SDTS_Terms_Description: SDTS_Point_and_Vector_Object_Type: Entity point Point_and_Vector_Object_Count: 48 SDTS_Terms_Description: SDTS_Point_and_Vector_Object_Type: Complete chain Point_and_Vector_Object_Count: 138 SDTS_Terms_Description: SDTS_Point_and_Vector_Object_Type: Complete chain Point_and_Vector_Object_Count: 928 SDTS_Terms_Description: SDTS_Point_and_Vector_Object_Type: Complete chain Point_and_Vector_Object_Count: 126 SDTS_Terms_Description: SDTS_Point_and_Vector_Object_Type: GT-polygon composed of chains Point_and_Vector_Object_Count: 15 Entity_and_Attribute_Information: Overview_Description: Entity_and_Attribute_Overview: The metadata file was written to provide an overview for the complete database in geodatabase format. Shapefiles derived from the geodatabase may have abbreviated or shortened field names. For more descriptive descriptions of the attributes please see the metadata files associated with each feature class. The database contains three feature datasets: CadastralFeatures, GeologicMap, and QuadrangleBoundaries. The GeologicMap feature dataset contains the geologic data. CadastralFeatures contains several topographic map vector layers that augment the raster topographic base. QuadrangleBoundaries contains both the individual mapped topograhic boundaries and the full map boundary. The QuadBoundaries feature class found in this feature dataset contains the boundaries for each of the USGS Topographic Quadrangles, and the NAME field contains each quadrangle name. Below is an attribute overview for the feaures found in the GeologicMap feature dataset. Detailed metadata files can be found associated with the other feature classes. There are three line feature classes: CartographicLines, ContactsAndFaults, and GeologicLines. The CartographicLines feature class contains the locations of cartographic leaders. These designations are stored in the Type field. The Contacts and Faults feature class contains the locations of the geologic contacts, faults, dikes, scarps, and water boundaries. The Type field contains the designtions for each, and IsConcealed, ExistenceConfidence, IdentityConfidence, and LocationConfidence fields contain whether the object is concealed, how well the author can recognize the line, and how well the author can locate the line. The GeologicLines feature class contains the locations of moraine crests, fissure vents, lavaflow paths, and open cracks. These feature classes also contains other fields specified by the NCGMP09 database schema. There are two polygon feature classes: MapUnitPolys, and OtherPolys. The MapUnitPolys contains the boundaries for geologic units. Geologic unit symbols for each polygon is stored in the MapUnit field, and IdentityConfidence describes how well the author can identify the map unit at this location. These MapUnit can be joined or related to geologic names and descriptions by using the MapUnit field in the UnitDescriptions table contained in this database. The OtherPolys feature class contains the boundaries of Cinder Cones. These feature classes also contains other fields specified by the NCGMP09 database schema. There are four point feature class in this release, VolcanicPoints and OrientationPoints. The VolcanicPoints feature class contains the locations of all of the volcanic vents in the map area, an the point type is stored in the Type field. The OrientationPoints feature class containns the locations of bedding and structural measurements. The Type, Azimuth, and Inclination fields contain the data describing the measurement. The GeoChemPoints feature class contains the sample locality and all of the geochemistry measurements. The GeoChronPoints feature class contains the locations of the geochronology measurements taken. The author's preferred age is listed in the PreferredAge field with PreferredAgeError. Other fields dedicated to describing other 40Ar/39Ar age determinations. These feature classes also contain other fields specified by the NCGMP09 database schema. The release also contains three tables. The DataSources table contains the references used in the creation of this map. The DataSourcesID is the foriegn key to the DataSources_ID field in all other tables. The DescriptionOfMapUnits table contains the complete geologic unit name, age, and description for each of the geologic unit symbol on the map in the MapUnit, Name, Age, and Description fieilds. The Glossary table provides definitions in the Definition field for many of the terms used in the database. These feature classes also contains other fields specified by the NCGMP09 database schema. Finally, this release contains an annotation feature class, Annotation. This feature class provides cartographic names and labels for the map and all fields are specified by ESRI Distribution_Information: Distributor: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Address: Address_Type: mailing Address: Denver Federal Center Address: Box 25286 City: Denver State_or_Province: Colorado Postal_Code: 80225-0046 Country: US Contact_Voice_Telephone: (303)202-4200 Contact_Voice_Telephone: 1-888-ASK-USGS Contact_Facsimile_Telephone: (303)202-4695 Contact_Electronic_Mail_Address: infoservices@usgs.gov Distribution_Liability: This database has been approved for release and publication by the Director of the U.S. Geological Survey (USGS). Although this database has been subjected to rigorous review and is substantially complete, the USGS reserves the right to revise the data pursuant to further analysis and review. Furthermore, it is released on condition that neither the USGS nor the United States Government may be held liable for any damages resulting from its authorized or unauthorized use. Standard_Order_Process: Digital_Form: Digital_Transfer_Information: Format_Name: ESRI file geodatabase Format_Version_Number: ESRI ArcCatalog 10.2 File_Decompression_Technique: WinZip Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: https://pubs.er.usgs.gov/publication/pp1812 Metadata_Reference_Information: Metadata_Date: 20150713 Metadata_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Person: Joel E. Robinson Contact_Position: Geologist Contact_Address: Address_Type: mailing Address: 345 Middlefield Road Address: MS 910 City: Menlo Park State_or_Province: CA Postal_Code: 94025 Country: US Contact_Voice_Telephone: 650-329-5322 Contact_Facsimile_Telephone: 650-329-5203 Contact_Electronic_Mail_Address: jrobins@usgs.gov Contact_Instructions: Please contact via e-mail Metadata_Standard_Name: FGDC Content Standard for Digital Geospatial Metadata Metadata_Standard_Version: FGDC-STD-001-1998 Metadata_Time_Convention: local time