Identification_Information: Citation: Citation_Information: Originator: Bawiec, Walter J. Publication_Date: 2000 Title: COVERAGE PERMAU -- Permissive Terranes on the Island of Puerto Rico for Placer Au-PGE, Cu-Ag Manto, and Porphyry Copper Geospatial_Data_Presentation_Form: Map Series_Information: Series_Name: U.S. Geological Survey Open-File Report Issue_Identification: USGS OFR 98-38 Publication_Information: Publication_Place: Reston, Virginia Publisher: U.S. Geological Survey Online_Linkage: () Originator: Ramon Alonzo Harris Originator: Dennis P. Cox Originator: Andrew Griscom Originator: Bruce R. Lipin Originator: Sherman P. Marsh Originator: Greg E. McKelvey Originator: Norman J Page Originator: Johannes H. Schellekens Description: Abstract: The delineation of tracts that are permissive for undiscovered mineral deposits of a specific type requires the input and assimilation of geologic information from multiple earth-science disciplines. The preliminary tracts are usually based upon the distribution of permissive host rocks, which may contain known occurrences. Host rocks are assembled into favorable geologic terranes based upon rock type, age, and (or) depositional environment. Geochemical and geophysical data (magnetism, gravity) can be used to either extend or delete parts of these terranes, especially with respect to surficial cover. Geochemical data show the presence of anomalous metallic elements, or indicative pathfinder elements, which provide circumstantial evidence for the presence of metallic minerals. Gravity and magnetism are important in understanding the geometry and extent of subsurface geology. The degree of known exploration is then examined to determine which areas could be considered as having been explored and (or) exhausted on the basis of previous investigations for each deposit type. The resultant permissive tract is the area that remains after elimination of all areas in which the deposit type could not possibly occur. Purpose: Mineral resource assessment methodology is a continually evolving process, and the tools for mineral resource assessment are constantly being improved. Unlike the oil and gas industry, which has relatively well-documented exploration and production statistics and a much longer history of petroleum-related resource assessment, the minerals industry is less well documented, subject to more variables, and has more complexities. The products from mineral resource assessments are also more diversified (Singer and Mosier, 1981). Initially, mineral assessments attempted only to highlight areas of potential exploration having suitable geologic characteristics. Qualitative assessments, delineating areas and characterizing them as to high, medium, or low potential on the basis of the favorability of geologic characteristics, were provided as mineral resource assessments, but were not found to be very useful when integrating information from other disciplines. With the development of new assessment tools, such as descriptive models and grade and tonnage models (Cox and Singer, 1986; Bliss, 1992), the quantitative mineral resource assessment method of estimating probabilistically the number of undiscovered deposits became possible. Mineral resource assessment has evolved to a point where government officials, policymakers, and managers of private enterprise can now integrate mineral resource potential with information from other disciplines. Supplemental_Information: PORPHYRY COPPER DEPOSITS The model Porphyry copper deposits consist of a stockwork of veinlets of quartz, chalcopyrite, and molybdenite in or near a porphyritic intrusion (Cox, 1986a). Rock types include tonalite to monzogranite stocks and breccia pipes intrusive into batholithic, volcanic, or sedimentary rocks. The ore grade is, in general, positively correlated with the density of veinlets and mineralized fractures. Minerals include chalcopyrite, pyrite and molybdenite, and peripheral vein or replacement deposits contain chalcopyrite, pyrite, galena, and (or) gold. The outermost deposits may have veins of copper, silver, and antimony sulfides, barite, and gold. The median tonnage of 208 porphyry copper deposits worldwide is 140 million mt, and 10 percent have tonnages of 1.1 billion mt or more. Median copper grade is 0.54 percent, and 10 percent of the deposits have molybdenum grades of 0.03 percent or more (Singer and others, 1986). Porphyry copper deposits have been described by a generalized model (Cox 1986b) that includes several subtypes. The model has been subdivided into a porphyry copper-gold model (Cox, 1986b) and a porphyry copper-molybdenum model (Cox, 1986c), but for the assessment of undiscovered deposits of Puerto Rico, there is insufficient information to prepare separate tracts for these two deposit types. In the Lares-Adjuntas area, however, an estimate of undiscovered deposits of the porphyry copper-gold type was made. Examples In Puerto Rico Four porphyry copper-gold deposits have been discovered in the Lares- Adjuntas region: Tanamá (site 161), Helecho (site 179), Cala Abajo (site 75), and Piedra Hueca (site 71). The last two may be segments of the same deposit and are commonly referred to as the Río Viví deposits. These deposits have been explored by drilling and, with the exception of Helecho, their grades and tonnages have been announced. In addition, several occurrences of this type are known, including Laundry Creek (site 158), Copper Creek (site 159), and Sapo Allegre (site 73). These deposits and occurrences are discussed in a subsequent section. There are eight porphyry copper occurrences outside of the Lares-Adjuntas region for which there is insufficient information to classify them by subtype. Three of these have been partially explored: the Barranquitas Prospect (site 203), Rio Cuyon (site 52), and La Muda (site 114). About 40 km east of the Río Viví area is the Barranquitas Prospect (site 203), a porphyry stock weakly mineralized with copper (Pease, 1966). The prospect has some characteristics of a porphyry copper-gold system; soil samples from near the stock contain as much as 0.2 ounces per ton (6 PPM) Au. Drilling during the 1950's did not encounter economic concentration of copper mineralization and the gold grade of the mineralized rock was not known. Río Cuyon (site 52) consists of a surface oxide zone enriched in copper, which was measured to be 1,500 PPM Cu and 4,000 PPM Mo. Drilling during exploration demonstrated that rock characterized by these analytical data did not continue at depth. Drilling offered little encouragement for copper porphyry mineralization at depth, and potential for gold, while untested, was not considered high. La Muda (site 114) is an inactive prospect that occurs, in addition to other porphyry copper occurrences, along the La Muda Fault Zone. Of the seven drill holes that were drilled, the best analytical data from core data show 0.18 percent Cu and 0.28 percent Mo (Bergey, 1967). This deposit is considered well explored and of limited potential (Bergey, 1967). The remaining identified occurrences appear to be small, but are unexplored in the subsurface. Permissive tracts Tract delineation for undiscovered porphyry copper deposits is dependent upon the distribution of intrusive rocks, geophysical patterns, known occurrences, and geochemical signature. Unlike tracts defined for other mineral deposit types in this study, large areas of Puerto Rico are considered to be permissive for this deposit type. In order to be more discriminating and restrictive in applying this information, only areas that had the strongest supporting evidence for the occurrence of this deposit type are considered favorable. The tract that is permissive for undiscovered porphyry copper deposits is limited in the north by a carbonate wedge that increases in thickness to the north. This boundary line is located to approximate the gravity gradient. A combination of the "Gravity Boundary Map" and the geologic terrane map were used to delineate the remaining boundaries of the permissive tract. Within this permissive tract, we have delineated an area favorable for porphyry copper-gold deposits as discussed in the following section. Undiscovered deposits Consideration of the high level of exploration for these deposits in Puerto Rico, the tendency to find the larger deposits first, and the small size and low grade of the known occurrences, led the assessment team to assign a low probability to the existence of undiscovered deposits near the surface consistent with the porphyry copper grade and tonnage model of Singer and others (1986). Probabilistic estimates of the number of undiscovered deposits of this general porphyry copper type were not made. However, an estimate of undiscovered porphyry copper-gold deposits, for which estimates of numbers of undiscovered deposits was possible, is given in the following section. COPPER-SILVER MANTO DEPOSITS Small lenses and veins of native copper, chalcocite, and bornite (sites 15, 16, and 17) are found in the Blacho Tuff Member of the Pozas Formation 3-4 km southwest of Ciales. The low sulfur content of this mineralized rock suggests that it is not derived from hydrothermal fluids emanating from plutonic sources, as are most vein deposits in Puerto Rico. Their occurrence in subaerial volcanic rocks including red-hued dacite tuff and minor fluvial sedimentary rock suggests an affinity with the copper-silver manto deposits of Chile, of which El Jardin Deposit (Mayer and Fontboté, 1990) is a good example. The known deposits near Ciales are small, but there is a chance of medium-size, high-grade copper-silver deposits in this subaerial volcanic environment. The permissive area includes the Pozas Formation. Because no grade and tonnage model is available, we do not estimate a specific number of undiscovered deposits. PLACER GOLD-PLATINUM-GROUP ELEMENTS The model The descriptive model for the placer gold-platinum-group-elements (PGE) deposit type includes detrital elemental gold and alloys of platinum-group elements in grains and (rarely) nuggets in gravel, sand, silt, clay, and their consolidated equivalents, in alluvial, beach, eolian, and (rarely) glacial deposits (Yeend, 1986). The depositional environment for placer gold-PGE includes transitional areas where streams loose energy and cannot carry the sediment load carried by a higher energy stream, such as entering lower stream gradients, the inside point bars of stream meanders, below rapids and falls, beneath boulders, and in vegetation mats. Examples in Puerto Rico Production of gold within Puerto Rico was first reported during its early years of settlement, when gold-bearing sands of river systems were exploited by the early settlers during the years 1509-36 (Picó, 1974). There are three placer gold-PGE deposits and one unclassified occurrence of gold. Río Caliente (site 200) was reportedly mined in the late 1930's at about the same time the Barranquitas stock area was being prospected for gold (Briggs and Gelabert, 1962). Small dams were built on the southern headwaters of the Río Caliente north of the Barranquitas stock to store water for sluicing operations. The Luquillo Mountains gold placers (site 100) are represented by this one occurrence. Placer mining was conducted on the Ríos Fajardo, Luquillo, Mameyes, Rio Grande, and Sabana, which drain the El Yunque forest. Palos Blancos (site 72) is recorded by Cox and Briggs (1972) to be a former placer site; site 140 contains anomalous gold within chert of the Bermeja complex. Permissive tracts Tract delineation for placer Au-PGE is based primarily on known historical river placer sites and drainage patterns that are downstream from these known occurrences. Undiscovered deposits Due to the high degree of exploration onshore, but relatively little knowledge of offshore sediments, other than surficial sediment types, the assessment team agreed that there was a one percent chance of one or more undiscovered deposits, most likely in the offshore area. There is a documented occurrence of a gold grain being found offshore (Grosz, personnel commun., 1992). Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 1999 Status: Progress: Complete Maintenance_and_Update_Frequency: None Planned Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -67.27252168 East_Bounding_Coordinate: -65.58590547 North_Bounding_Coordinate: 18.70553244 South_Bounding_Coordinate: 17.61451692 Keywords: Theme: Theme_Keyword_Thesaurus: None Theme_Keyword: Permissive Terranes Placer Au-PGE Cu-Ag Manto Porphyry Copper Place: Place_Keyword_Thesaurus: None Place_Keyword: Puerto Rico Access_Constraints: None Use_Constraints: Anyone who uses these data must cite U.S. Geological Survey. These data are not to be used at scales showing more detail than 1:200,000. Point_of_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Bawiec, Walter J. Contact_Organization: U.S. Geological Survey Contact_Position: Geologist Contact_Address: Address_Type: mailing address Address: 954 National Center 12201 Sunrise Valley Drive City: Reston State_or_Province: Virginia Postal_Code: 20192 Country: United States Contact_Voice_Telephone: (703)648-6148 Contact_Facsimile_Telephone: (703)648-6383 Contact_Electronic_Mail_Address: wbawiec@usgs.gov Data_Set_Credit: The permissive terranes for the mineral deposit models of Puerto Rico were drawn by a team of earth scientists and economic geologists familiar with Puerto Rico. They included W.J. Bawiec, R. Alonzo, D.P. Cox, A. Griscom, B.R. Lipin, S.P. Marsh, G.E. McKelvey, N.J Page, J.H. Schellekens. Native_Data_Set_Environment: Windows_NT, 4.0, Intel ARC/INFO version 7.1.1 Data_Quality_Information: Attribute_Accuracy: Attribute_Accuracy_Report: The purpose of this map coverage is to show the spatial distribution of permissive terranes for the following mineral deposit types: Placer Gold-Platinium Group Elements, Copper-Silver Manto, and Porphyry Copper deposits. The permissive terranes were drawn based upon the geology, geologic terranes, geochemical anomalies, subsurface geophysical patterns, distance from intrusions, known deposits, and mineral occurrences. The boundaries of these permissive terranes were based upon the agreement of a team of earth scientists, inclusing geologists, geochemists, geophysists, and economic geologists. These boundaries are thought to be accurate based upon the information used in the study. However, as more detailed information becomes available in the future, the shape of the spatial distributions of these mineral deposit types are subject to change. Logical_Consistency_Report: Polygon and chain-node topology present. All polygons have a label and all polygons are closed. Completeness_Report: The delineation of tracts that are permissive for undiscovered mineral deposits of a specific type requires the input and assimilation of geologic information from multiple earth-science disciplines. The preliminary tracts are usually based upon the distribution of permissive host rocks, which may contain known occurrences. Host rocks are assembled into favorable geologic terranes based upon rock type, age, and (or) depositional environment. Geochemical and geophysical data (magnetism, gravity) can be used to either extend or delete parts of these terranes, especially with respect to surficial cover. Geochemical data show the presence of anomalous metallic elements, or indicative pathfinder elements, which provide circumstantial evidence for the presence of metallic minerals. Gravity and magnetism are important in understanding the geometry and extent of subsurface geology. The degree of known exploration is then examined to determine which areas could be considered as having been explored and (or) exhausted on the basis of previous investigations for each deposit type. The resultant permissive tract is the area that remains after elimination of all areas in which the deposit type could not possibly occur. Positional_Accuracy: Horizontal_Positional_Accuracy: Horizontal_Positional_Accuracy_Report: The boundaries used to delineate the outlines of the permissive terranes consist of geologic contacts, geologic terranes, distances from intrusions, and geophysical magnetic and gravity boundaries. In some instances, when they follow a geologic contact, they are precisely located from the 1:100,000 scale geologic map; but in other instances, such as following a gradient in a magnetic map or picking a distance from an intrusion, the boundaries are much less precise and only indicate a general location. Spatial_Data_Organization_Information: Direct_Spatial_Reference_Method: Vector Point_and_Vector_Object_Information: SDTS_Terms_Description: SDTS_Point_and_Vector_Object_Type: Point Point_and_Vector_Object_Count: 28 SDTS_Point_and_Vector_Object_Type: String Point_and_Vector_Object_Count: 1514 SDTS_Point_and_Vector_Object_Type: GT-polygon composed of chains Point_and_Vector_Object_Count: 28 Spatial_Reference_Information: Horizontal_Coordinate_System_Definition: Planar: Map_Projection: Map_Projection_Name: Polyconic Polyconic: Latitude_of_True_Scale: 18 Longitude_of_Central_Meridian: -67 False_Easting: 0.00000 False_Northing: 0.00000 Planar_Coordinate_Information: Planar_Coordinate_Encoding_Method: coordinate pair Coordinate_Representation: Abscissa_Resolution: 0.0354962907731 Ordinate_Resolution: 0.0354962907731 Planar_Distance_Units: Meters Geodetic_Model: Horizontal_Datum_Name: North American Datum of 1927 Ellipsoid_Name: Clarke 1866 Semi-major_Axis: 6378206.4 Denominator_of_Flattening_Ratio: 294.98 Entity_and_Attribute_Information: Overview_Description: Entity_and_Attribute_Overview: The following ITEMS are found in PERMAU.PAT and describe the attributes associated with the coverage PERMAU. The ITEMS AREA, PERIMETER, PERMAU#, and PERMAU-ID are Arc/Info generated and never to be altered. The ITEMS FMATN, COLR, COLR2, and SHADE were created to aid in the development and editing of the coverage. All values found in these items are outdated and no longer useful to the user except for COLR2. COLR2 contains the attribute by which each terrane is colored (see PERMAU.AML in AML folder)and can also be used to select by terrane type. The values of COLR2 are: 4 - Placer Au-PGE; 151 - Background color; 10 - Cu-Ag Manto; 3- Porphyry Copper. The ITEMS found in PERMAU.AAT to attribute arcs are all Arc/info generated and should not be altered. > >PERMAU.PAT: > >COLUMN ITEM NAME WIDTH OUTPUT TYPE N.DEC ALTERNATE NAME > 1 AREA 4 12 F 3 > 5 PERIMETER 4 12 F 3 > 9 PERMAU# 4 5 B - > 13 PERMAU-ID 4 5 B - > 17 FMATN 5 5 C - > 22 COLR 4 4 F 0 > 26 COLR2 4 4 F 0 > 30 SHADE 4 4 F 0 > > >PERMAU.AAT: > >COLUMN ITEM NAME WIDTH OUTPUT TYPE N.DEC ALTERNATE NAME > 1 FNODE# 4 5 B - > 5 TNODE# 4 5 B - > 9 LPOLY# 4 5 B - > 13 RPOLY# 4 5 B - > 17 LENGTH 4 12 F 3 > 21 PERMAU# 4 5 B - > 25 PERMAU-ID 4 5 B - > > Entity_and_Attribute_Detail_Citation: none Distribution_Information: Distributor: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Information Services Contact_Address: Address_Type: mailing address Address: Box 25286, Denver Federal Center City: Denver State_or_Province: Colorado Postal_Code: 80225-0286 Country: United States Contact_Voice_Telephone: 1-800-USA-MAPS Contact_Electronic_Mail_Address: http://mapping.usgs.gov/esic/esic.html Distribution_Liability: This Compact Disc-Read Only Memory (CD-ROM) publication was prepared by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, make any warranty, expressed or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed in this report, or represents that its use would not infringe privately owned rights. Reference therein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. Any views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof. Although all data and software published on this CD-ROM have been used by the USGS, no warranty, expressed or implied, is made by the U.S. Geological Survey as to the accuracy of the data and related materials and/or the functioning of the software. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of this data, software, or related materials. Graphical map depictions on this disc are intended to be used within the map scale limits applicable to the source data. Although software enables the user to show images on the disc at various scales, the user is cautioned to refer to the source documentation for the appropriate map scale limitations. Metadata_Reference_Information: Metadata_Date: 19991029 Metadata_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Person: Bawiec, Walter J. Contact_Position: Geologist Contact_Address: Address_Type: mailing address Address: 954 National Center City: Reston State_or_Province: Virginia Postal_Code: 20192 Country: United States Contact_Voice_Telephone: (703)648-6148 Contact_Facsimile_Telephone: (703)648-6383 Contact_Electronic_Mail_Address: wbawiec@usgs.gov Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata Metadata_Standard_Version: Version of June 8, 1994 Metadata_Access_Constraints: none Metadata_Use_Constraints: none