{"text_format":"dbase-jsonl-2026-09-30","columns":[{"name":"AREA","type":"float","width":19,"decimals":11},{"name":"PERIMETER","type":"float","width":19,"decimals":11},{"name":"MAP_UNIT","type":"character","width":10},{"name":"SUR_BED","type":"character","width":254},{"name":"FORMATION","type":"character","width":254},{"name":"MEMBER","type":"character","width":254},{"name":"ROCK_CLASS","type":"character","width":254},{"name":"FOLIA","type":"character","width":254},{"name":"REL_AGE","type":"character","width":254},{"name":"MINERAL","type":"character","width":254},{"name":"FOSSIL","type":"character","width":254},{"name":"COLOR","type":"character","width":254},{"name":"LITHOLOGY","type":"character","width":80},{"name":"UNIT_DESCR","type":"character","width":200},{"name":"AGE_DESCR","type":"character","width":254},{"name":"DMU","type":"character","width":254}],"n_rows":14,"rows_kept":14,"cut":false,"deleted_skipped":0,"read_ended":"whole","bounds":"16MiB/16384/4096/first_that_fit","version":"dbase_level_three","encoding_class":"enc_single_byte","reader":"statdb_count/9"}
[5.36171000000e+005,4.17441015625e+003,"Olj","Bedrock","Lake Jackson Pluton",null,"Metasedimentary","Foliated and lineated","Middle Ordovician","albite, quartz, and perthite; phyllite",null,"Green-red","Biotite and muscovite metatonalite, contains inclusions of phyllite","Foliated and lineated biotite and muscovite metatonalite composed of albite, quartz, and perthite; contains inclusions of phyllite from unit OCp. SHRIMP U-Pb single zircon age of 461+-7 Ma",null,"Lake Jackson pluton (Middle Ordovician)"]
[3.09920000000e+006,8.43340039063e+003,"OCp","Bedrock","Phyllite",null,"Metasedimentary",null,"Ordovician and (or) Cambrian","phyllite",null,"Gray and green","Phyllite and metasiltstone","Phyllite and metasiltstone",null,"Phyllite (Ordovician and (or) Cambrian)"]
[3.52145000000e+007,2.72296992188e+004,"Olr","Bedrock","Lunga Reservoir",null,"Sedimentary","Sedimentary mélange that resembles a granitoid","Ordovician","quartz and plagioclase, mica-schist, calc-silicate",null,null,"Micaceous quartzofeldspathic groundmass of quartz and plagioclase","Micaceous quartzofeldspathic groundmass of rounded grains of quartz and plagioclase supports pebbles and cobbles of clear-milky quartz, mica schist, calc-silicate rocks, mafic and ultramafic rocks",null,"Lunga Reservoir Formation (Ordovician)"]
[2.47384003906e+004,8.17395996094e+002,"CZum","Bedrock","Mafic and ultramafic rocks",null,null,"Composite masses, relict gabbroic texture","Neoproterozoic and (or) Cambrian","epidote-hornblende gneiss and amphibolite",null,"Green","Epidote-hornblende gneiss and amphibolite","Composite masses of green, medium to coarse grained epidote-hornblende gneiss and amphibolite, locally having relict gabbroic texture. Interpreted to be a large clasts and blocks in the Lunga Reservoi",null,"Mafic and ultramafic rocks (Cambrian and (or) Neoproterozoic)"]
[9.90787031250e+004,1.60941003418e+003,"CZum","Bedrock","Mafic and ultramafic rocks",null,null,"Composite masses, relict gabbroic texture","Neoproterozoic and (or) Cambrian","epidote-hornblende gneiss and amphibolite",null,"Green","Epidote-hornblende gneiss and amphibolite","Composite masses of green, medium to coarse grained epidote-hornblende gneiss and amphibolite, locally having relict gabbroic texture. Interpreted to be a large clasts and blocks in the Lunga Reservoi",null,"Mafic and ultramafic rocks (Cambrian and (or) Neoproterozoic)"]
[1.63805000000e+006,8.11185009766e+003,"Ocw","Bedrock","Chopawamsic",null,"Metavolcanic and Metasedimentary","Interbedded and interlayered","Upper Ordovician",null,null,"Gray and green","Silicic & mafic flows, breccias & tuffs w slate, phyllite, schist, metasandstone","Vesicular and porphyritic silicic, intermediate & mafic volcanic flows, breccias & tuffs interbedded & interlayered w/ volcanogenic sediments metamorphosed to slate, phyllite, schist & metasandstone.","SHRIMP U-Pb age of 454+/-5 My from metarhyolite layer (Horton and others, 1998) and 471 +/- 1.3 My from metarhyolite and 470+/-1.4 My from metabasalt (Coler and others, 2000)","Chopawamsic Formation (Upper Ordovician) Metavolcanic and metasedimentary rocks"]
[1.38263000000e+005,2.06228002930e+003,"Oi","Bedrock",null,"Felsic intrusive (?) rocks","Metavolcanic and Metasedimentary","Foliated","Silurian",null,null,null,"Biotite metatonalite and hornblende quartz diorite with epidote, sodic plagio...","Foliated, biotite metatonalite and hornblende quartz diorite with epidote, sodic plagioclase, chlorite, actinolite. SHRIMP U-Pb zircon age of 434+/-6 Ma from metatonalite (Horton and others, 1998)","SHRIMP U-Pb zircon age of 434+/-6 Ma from metatonalite (Horton and others, 1998)","Felsic igneous rocks (Silurian)"]
[7.14714990234e+003,4.40183013916e+002,"Oi","Bedrock",null,"Felsic intrusive (?) rocks","Metavolcanic and Metasedimentary","Foliated","Silurian",null,null,null,"Biotite metatonalite and hornblende quartz diorite with epidote, sodic plagio...","Foliated, biotite metatonalite and hornblende quartz diorite with epidote, sodic plagioclase, chlorite, actinolite. SHRIMP U-Pb zircon age of 434+/-6 Ma from metatonalite (Horton and others, 1998)","SHRIMP U-Pb zircon age of 434+/-6 Ma from metatonalite (Horton and others, 1998)","Felsic igneous rocks (Silurian)"]
[4.59436000000e+006,1.52139003906e+004,"Oi","Bedrock",null,"Felsic intrusive (?) rocks","Metavolcanic and Metasedimentary","Foliated","Silurian",null,null,null,"Biotite metatonalite and hornblende quartz diorite with epidote, sodic plagio...","Foliated, biotite metatonalite and hornblende quartz diorite with epidote, sodic plagioclase, chlorite, actinolite. SHRIMP U-Pb zircon age of 434+/-6 Ma from metatonalite (Horton and others, 1998)","SHRIMP U-Pb zircon age of 434+/-6 Ma from metatonalite (Horton and others, 1998)","Felsic igneous rocks (Silurian)"]
[3.98430000000e+006,1.42885996094e+004,"Ocw","Bedrock","Chopawamsic",null,"Metavolcanic and Metasedimentary","Interbedded and interlayered","Upper Ordovician",null,null,"Gray and green","Silicic & mafic flows, breccias & tuffs w slate, phyllite, schist, metasandstone","Vesicular and porphyritic silicic, intermediate & mafic volcanic flows, breccias & tuffs interbedded & interlayered w/ volcanogenic sediments metamorphosed to slate, phyllite, schist & metasandstone.","SHRIMP U-Pb age of 454+/-5 My from metarhyolite layer (Horton and others, 1998) and 471 +/- 1.3 My from metarhyolite and 470+/-1.4 My from metabasalt (Coler and others, 2000)","Chopawamsic Formation (Upper Ordovician) Metavolcanic and metasedimentary rocks"]
[4.10210000000e+006,1.19137001953e+004,"Ocg","Bedrock",null,"Breccia and greenstone",null,null,null,null,null,null,null,null,null,"Chopawamsic Formation (Upper Ordovician) Breccia and greenstone"]
[3.58778000000e+006,1.33525996094e+004,"Ocw","Bedrock","Chopawamsic",null,"Metavolcanic and Metasedimentary","Interbedded and interlayered","Upper Ordovician",null,null,"Gray and green","Silicic & mafic flows, breccias & tuffs w slate, phyllite, schist, metasandstone","Vesicular and porphyritic silicic, intermediate & mafic volcanic flows, breccias & tuffs interbedded & interlayered w/ volcanogenic sediments metamorphosed to slate, phyllite, schist & metasandstone.","SHRIMP U-Pb age of 454+/-5 My from metarhyolite layer (Horton and others, 1998) and 471 +/- 1.3 My from metarhyolite and 470+/-1.4 My from metabasalt (Coler and others, 2000)","Chopawamsic Formation (Upper Ordovician) Metavolcanic and metasedimentary rocks"]
[1.65147000000e+006,1.41824003906e+004,"Oq","Bedrock","Quantico",null,null,"Layered","Upper Ordovician",null,"Ordovician marine fossils","Dark gray","Slate; graded metagraywacke, quartz-rich layers & tuffaceous metavolcanic rocks","Dark slate, rich in carbon and pyrite that contains layers of graded metagraywacke,  thin quartz-rich layers, and tuffaceous metavolcanic rocks","SHRIMP U-Pb zircon age of 451+/- 6 Ma from metamorphosed lapilli tuff layer in lower part of pelitic sequence which contains Ordovician marine fossils (Pavlides and others, 1980)","Quantico Formation (Upper Ordovician)"]
[3.08868000000e+005,5.73791992188e+003,"Oi","Bedrock",null,"Felsic intrusive (?) rocks","Metavolcanic and Metasedimentary","Foliated","Silurian",null,null,null,"Biotite metatonalite and hornblende quartz diorite with epidote, sodic plagio...","Foliated, biotite metatonalite and hornblende quartz diorite with epidote, sodic plagioclase, chlorite, actinolite. SHRIMP U-Pb zircon age of 434+/-6 Ma from metatonalite (Horton and others, 1998)","SHRIMP U-Pb zircon age of 434+/-6 Ma from metatonalite (Horton and others, 1998)","Felsic igneous rocks (Silurian)"]