Despite study by several investigators many features of the Precambrian supercontinent Rodinia remain enigmatic. 40 Ar/ 39 Ar geochronology of detrital muscovites from Mesoproterozoic sedimentary rocks across the southwest United States is employed in an attempt to refine models for continental alignment within Rodina, determine stratigraphic age and provenance. Specifically, detrital muscovite age data are reported from the Apache group in southeast Arizona, the De Baca group in New Mexico and the Unkar group in the Grand Canyon. Significant provenance variations are observed and new constraints on the age and correlations can be deduced. Approximately 310 single muscovite ages from the Pioneer shale unit of the Apache group yield a strongly bimodal age population with peaks at about 1.4 Ga and 1.65 Ga. This result is consistent with a U/Pb zircon age of 1.33 Ga from a volcanic unit within the Pioneer and the age populations support a southwestern Laurentia source. Stratigraphically higher in the Apache group, the Dripping Springs formation has a more diverse age population that ranges between 1.20 to 1.60 Ga. The youngest apparent ages indicate that the Dripping Springs formation is no older than 1.2 Ga and challenges correlations of the overlying Mescal limestone with the well dated 1254 Ma (U/Pb zircon) Bass formation in Grand Canyon. The De Baca Group is constraint to be older than about 1.1 Ga based on an inferred 1.1 Ga age for crosscutting diabase. The detrital muscovites from a shale horizon have a dominant age population at about 1.4 Ga with smaller peaks 1.6 Ga and 1.2 Ga. The 1.4 Ga and 1.7 Ga ages are likely locally derived from Meso and Paleoproterozoic crust to the north. The younger 1.2 Ga dates may suggest a depositional age that is less then 1.2 Ga. Muscovite from a quartzite unit in close proximity to the diabase has ages between about 0.5 to 1.6 Ga. The youngest crystals have presumably under gone postdeposition argon loss and/or represent growth of new fine-grained mica at this time. Ages between 1.1 and 1.2 Ga may be provenance ages, but factors such as reheating associated with sill emplacement and post-deposition alteration may have caused argon loss. We cannot be specific about the depositional age of this unit. Two formations from the Unkar group from the Grand Canyon were investigated. A sandstone layer within the Hotauta conglomerate below a 1.254 Ga ash horizon yields dominantly 1.65 Ga muscovite with a single grain yielding a 1.4 Ga apparent age. These ages are common for the underlying basement, presumably locally derived and consistent with the Hotauta being older than 1.25 Ga. Higher in the Unkar section, several samples of the Dox Formation were sampled. Over 500 crystals display an age range from about 1.14 to 1.25 Ga with no 1.4 Ga or 1.65 Ga detritus. 1.11 Ga dikes and sills cut the Dox and therefore the depositional age of the Dox is constrained to be 1.11 to 1.14 Ga. This result indicates a Grenville source
{"title":"PROBING THE SECRETS OF RODINIA: PIECES OF THE SUPERCONTINENT PUZZLE EXTRACTED FROM 40AR/39AR GEOCHRONOLOGY OF DETRITAL MUSCOVITES","authors":"K. Fletcher, M. Heizler","doi":"10.56577/sm-2004.678","DOIUrl":"https://doi.org/10.56577/sm-2004.678","url":null,"abstract":"Despite study by several investigators many features of the Precambrian supercontinent Rodinia remain enigmatic. 40 Ar/ 39 Ar geochronology of detrital muscovites from Mesoproterozoic sedimentary rocks across the southwest United States is employed in an attempt to refine models for continental alignment within Rodina, determine stratigraphic age and provenance. Specifically, detrital muscovite age data are reported from the Apache group in southeast Arizona, the De Baca group in New Mexico and the Unkar group in the Grand Canyon. Significant provenance variations are observed and new constraints on the age and correlations can be deduced. Approximately 310 single muscovite ages from the Pioneer shale unit of the Apache group yield a strongly bimodal age population with peaks at about 1.4 Ga and 1.65 Ga. This result is consistent with a U/Pb zircon age of 1.33 Ga from a volcanic unit within the Pioneer and the age populations support a southwestern Laurentia source. Stratigraphically higher in the Apache group, the Dripping Springs formation has a more diverse age population that ranges between 1.20 to 1.60 Ga. The youngest apparent ages indicate that the Dripping Springs formation is no older than 1.2 Ga and challenges correlations of the overlying Mescal limestone with the well dated 1254 Ma (U/Pb zircon) Bass formation in Grand Canyon. The De Baca Group is constraint to be older than about 1.1 Ga based on an inferred 1.1 Ga age for crosscutting diabase. The detrital muscovites from a shale horizon have a dominant age population at about 1.4 Ga with smaller peaks 1.6 Ga and 1.2 Ga. The 1.4 Ga and 1.7 Ga ages are likely locally derived from Meso and Paleoproterozoic crust to the north. The younger 1.2 Ga dates may suggest a depositional age that is less then 1.2 Ga. Muscovite from a quartzite unit in close proximity to the diabase has ages between about 0.5 to 1.6 Ga. The youngest crystals have presumably under gone postdeposition argon loss and/or represent growth of new fine-grained mica at this time. Ages between 1.1 and 1.2 Ga may be provenance ages, but factors such as reheating associated with sill emplacement and post-deposition alteration may have caused argon loss. We cannot be specific about the depositional age of this unit. Two formations from the Unkar group from the Grand Canyon were investigated. A sandstone layer within the Hotauta conglomerate below a 1.254 Ga ash horizon yields dominantly 1.65 Ga muscovite with a single grain yielding a 1.4 Ga apparent age. These ages are common for the underlying basement, presumably locally derived and consistent with the Hotauta being older than 1.25 Ga. Higher in the Unkar section, several samples of the Dox Formation were sampled. Over 500 crystals display an age range from about 1.14 to 1.25 Ga with no 1.4 Ga or 1.65 Ga detritus. 1.11 Ga dikes and sills cut the Dox and therefore the depositional age of the Dox is constrained to be 1.11 to 1.14 Ga. This result indicates a Grenville source ","PeriodicalId":142738,"journal":{"name":"New Mexico Geological Society, 2004 Annual Spring Meeting, Proceedings Volume","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130252589","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"HYDROGEOLOGIC STUDY OF THE COALBED METHANE RESOURCE IN THE RATON BASIN, NM","authors":"Christopher J. Haley, E. Vivoni, B. Brister","doi":"10.56577/sm-2004.679","DOIUrl":"https://doi.org/10.56577/sm-2004.679","url":null,"abstract":"","PeriodicalId":142738,"journal":{"name":"New Mexico Geological Society, 2004 Annual Spring Meeting, Proceedings Volume","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124543952","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"OLDEST RECORD OF DIPLOCAULUS CRANIAL MATERIAL FROM THE LOWER ABO FORMATION (EARLY WOLFCAMPIAN) AND ITS FAUNAL DISTRIBUTION IN NEW MEXICO","authors":"S. Harris, S. Lucas, D. Berman, A. Henrici","doi":"10.56577/sm-2004.680","DOIUrl":"https://doi.org/10.56577/sm-2004.680","url":null,"abstract":"","PeriodicalId":142738,"journal":{"name":"New Mexico Geological Society, 2004 Annual Spring Meeting, Proceedings Volume","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123560815","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"OXYGEN ISOTOPES OF MIDDLE PENNSYLVANIAN APATITIC CONODONTS AS A POTENTIAL RECORD OF PENNSYLVANIAN GLACIAL ICE VOLUME VARIATIONS","authors":"L. L. Neidel, M. Elrick, L. A. Scott","doi":"10.56577/sm-2004.714","DOIUrl":"https://doi.org/10.56577/sm-2004.714","url":null,"abstract":"","PeriodicalId":142738,"journal":{"name":"New Mexico Geological Society, 2004 Annual Spring Meeting, Proceedings Volume","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121878648","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
New Mexico Museum of Natural History’s Apachean age Whitaker Quarry block (C-8-82) has been under preparation since September, 2003. The volume of the 2-m-long, 1.4-m-wide, and 1.1-m-thick block is ~2 m3 . Microstratigraphic study of the block shows two fining upward sequences above a basal sandy siltstone. The upper 5 cm of this bed contains the ostracode, Darwinula , and the conchostracan, Lioestheria , that likely indicate a topographic low containing a (probably ephemeral) pond. This is the first report of calcareous microfossils from the Whitaker Quarry. The basal coarse silt and very fine sand of sequence one fines up to very fine silt with clay lenses. Sequence two has a basal matrix-supported conglomerate that fines up to very fine silt. All beds above the invertebrates contain elongate rip-up mud clasts that are closely aligned and trend WNW-ESE. These flow indicators agree well with the established scheme of a northwest-draining Chinle basin. The block stratigraphy indicates two flood events of increasing energy. To date, the fauna from the block comprises the aforementioned invertebrates; the redfieldiid fish Synorichthyes , the coelacanth fish Chinlea , the archosauromorph Vancleavea , a phytosaur, probably pertaining to Redondasaurus gregorii , and the theropod dinosaur Coelophysis bauri. Additionally, an indeterminate redfieldiid-like fish, several isolated enigmatic scutes, and teeth of a possible sphenosuchian or ornithischian dinosaur are present. In general, the fossil material coarsens up throughout the block. Sequence one contains (ascending order) the invertebrates, fish scales and bones, whole fish, non-dinosaurian tetrapods and
{"title":"MICROSTRATIGRAPHY AND FAUNA OF A SINGLE BLOCK FROM THE LATE TRIASSIC WHITAKER (COELOPHYSIS) QUARRY (ROCK POINT FORMATION: CHINLE GROUP), NORTH-CENTRAL NEW MEXICO","authors":"L. Rinehart, A. Heckert, S. Lucas, A. Hunt","doi":"10.56577/sm-2004.723","DOIUrl":"https://doi.org/10.56577/sm-2004.723","url":null,"abstract":"New Mexico Museum of Natural History’s Apachean age Whitaker Quarry block (C-8-82) has been under preparation since September, 2003. The volume of the 2-m-long, 1.4-m-wide, and 1.1-m-thick block is ~2 m3 . Microstratigraphic study of the block shows two fining upward sequences above a basal sandy siltstone. The upper 5 cm of this bed contains the ostracode, Darwinula , and the conchostracan, Lioestheria , that likely indicate a topographic low containing a (probably ephemeral) pond. This is the first report of calcareous microfossils from the Whitaker Quarry. The basal coarse silt and very fine sand of sequence one fines up to very fine silt with clay lenses. Sequence two has a basal matrix-supported conglomerate that fines up to very fine silt. All beds above the invertebrates contain elongate rip-up mud clasts that are closely aligned and trend WNW-ESE. These flow indicators agree well with the established scheme of a northwest-draining Chinle basin. The block stratigraphy indicates two flood events of increasing energy. To date, the fauna from the block comprises the aforementioned invertebrates; the redfieldiid fish Synorichthyes , the coelacanth fish Chinlea , the archosauromorph Vancleavea , a phytosaur, probably pertaining to Redondasaurus gregorii , and the theropod dinosaur Coelophysis bauri. Additionally, an indeterminate redfieldiid-like fish, several isolated enigmatic scutes, and teeth of a possible sphenosuchian or ornithischian dinosaur are present. In general, the fossil material coarsens up throughout the block. Sequence one contains (ascending order) the invertebrates, fish scales and bones, whole fish, non-dinosaurian tetrapods and","PeriodicalId":142738,"journal":{"name":"New Mexico Geological Society, 2004 Annual Spring Meeting, Proceedings Volume","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122511911","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"GRAVITY MODELING AND LITHOSPHERIC STRUCTURE BENEATH THE JEMEZ LINEAMENT, ARIZONA AND NEW MEXICO","authors":"J. MacCarthy, M. Roy","doi":"10.56577/sm-2004.705","DOIUrl":"https://doi.org/10.56577/sm-2004.705","url":null,"abstract":"","PeriodicalId":142738,"journal":{"name":"New Mexico Geological Society, 2004 Annual Spring Meeting, Proceedings Volume","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122165002","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"STRATIGRAPHY AND ORIGIN OF THE COONEY TUFF-REVISITED: MOGOLLON-DATIL VOLCANIC FIELD, SOUTHWESTERN, NEW MEXICO","authors":"J. C. Ratt�, W. Mcintosh, S. Lynch","doi":"10.56577/sm-2004.719","DOIUrl":"https://doi.org/10.56577/sm-2004.719","url":null,"abstract":"","PeriodicalId":142738,"journal":{"name":"New Mexico Geological Society, 2004 Annual Spring Meeting, Proceedings Volume","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132708053","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jurassic strata exposed along the southward extension of the Picuris-Pecos fault system south of Lamy, Santa Fe County (T12-13N, R10E), are assigned to the San Rafael Group (Entrada, Todilto and Summerville formations) and overlying Morrison Formation (Salt Wash, Brushy Basin and Jackpile members). A complete section of the San Rafael Group just north of Arroyo de La Jara consists of four lithostratigraphic units: (1) Dewey Bridge Member of Entrada Sandstone at the base of the section rests sharply on mudstones at the top of the Upper Triassic Chinle Group, is ~5 m thick and consists of white and pink, fine- to mediumgrained, ripple-laminated and trough-crossbedded sandstone; (2) Slick Rock Member of Entrada Sandstone is ~18 m thick and is yellow and gray, fine- to medium-grained sandstone with large trough crossbeds or tabular beds with climbing ripples; (3) Luciano Mesa Member of Todilto Formation, ~4 m thick, begins with 0.3 m of waterworked fine sandstone followed by 2.8 m of dark gray, finely laminated, kerogenic limestone capped by 0.7 m of brecciated and vuggy limestone; and (4) the Summerville Formation, ~19 m thick, is pale brown, cyclically bedded, very fine-grained sandstone and siltstone with some gypsum (6 m thick) overlain by interbedded gray limestone (with red chalcedony nodules) and reddish brown mudstone (~3 m thick) capped by ~10 m of reddish brown mudstone with thin, lenticular beds of trough-crossbedded sandstone. The base of the Morrison Formation on the Summerville Formation is a sharp, erosionally scoured surface overlain by medium-grained and pebbly sandstone at the base of the Salt Wash Member. This section of the
{"title":"STRATIGRAPHY OF THE JURASSIC SAN RAFAEL GROUP ALONG THE PICURIS-PECOS FAULT SYSTEM, SANTA FE COUNTY, NEW MEXICO","authors":"S. Lucas, S. Cather","doi":"10.56577/sm-2004.703","DOIUrl":"https://doi.org/10.56577/sm-2004.703","url":null,"abstract":"Jurassic strata exposed along the southward extension of the Picuris-Pecos fault system south of Lamy, Santa Fe County (T12-13N, R10E), are assigned to the San Rafael Group (Entrada, Todilto and Summerville formations) and overlying Morrison Formation (Salt Wash, Brushy Basin and Jackpile members). A complete section of the San Rafael Group just north of Arroyo de La Jara consists of four lithostratigraphic units: (1) Dewey Bridge Member of Entrada Sandstone at the base of the section rests sharply on mudstones at the top of the Upper Triassic Chinle Group, is ~5 m thick and consists of white and pink, fine- to mediumgrained, ripple-laminated and trough-crossbedded sandstone; (2) Slick Rock Member of Entrada Sandstone is ~18 m thick and is yellow and gray, fine- to medium-grained sandstone with large trough crossbeds or tabular beds with climbing ripples; (3) Luciano Mesa Member of Todilto Formation, ~4 m thick, begins with 0.3 m of waterworked fine sandstone followed by 2.8 m of dark gray, finely laminated, kerogenic limestone capped by 0.7 m of brecciated and vuggy limestone; and (4) the Summerville Formation, ~19 m thick, is pale brown, cyclically bedded, very fine-grained sandstone and siltstone with some gypsum (6 m thick) overlain by interbedded gray limestone (with red chalcedony nodules) and reddish brown mudstone (~3 m thick) capped by ~10 m of reddish brown mudstone with thin, lenticular beds of trough-crossbedded sandstone. The base of the Morrison Formation on the Summerville Formation is a sharp, erosionally scoured surface overlain by medium-grained and pebbly sandstone at the base of the Salt Wash Member. This section of the","PeriodicalId":142738,"journal":{"name":"New Mexico Geological Society, 2004 Annual Spring Meeting, Proceedings Volume","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133310692","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"QUANTIFYING THE INFLUENCE OF CALCIUM CARBONATE ACCUMULATION ON THE HYDRAULIC PROPERTIES OF SEMI ARID SOILS: SEVILLETA NATIONAL WILDLIFE REFUGE, NEW MEXICO","authors":"Ryan McLin","doi":"10.56577/sm-2004.709","DOIUrl":"https://doi.org/10.56577/sm-2004.709","url":null,"abstract":"","PeriodicalId":142738,"journal":{"name":"New Mexico Geological Society, 2004 Annual Spring Meeting, Proceedings Volume","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133886321","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"GEOLOGY OF THE SODA DAM TRAVERTINE DEPOSITS, SANDOVAL COUNTY, NEW MEXICO","authors":"William P. Moats","doi":"10.56577/sm-2004.711","DOIUrl":"https://doi.org/10.56577/sm-2004.711","url":null,"abstract":"","PeriodicalId":142738,"journal":{"name":"New Mexico Geological Society, 2004 Annual Spring Meeting, Proceedings Volume","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134052533","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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