{"title":"Hydrologic characteristics of the Ojo Alamo Sandstone, San Juan Basin, New Mexico","authors":"Clay L. Kilmer, T. E. Kelly","doi":"10.56577/ffc-43.409","DOIUrl":"https://doi.org/10.56577/ffc-43.409","url":null,"abstract":"","PeriodicalId":325871,"journal":{"name":"San Juan Basin IV","volume":"65 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125632151","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}
-The volcanic necks of the Rio Puerco Valley are among the most concentrated and best preserved examples in the world. They formed by erosion of poorly consolidated pyroclastic material surrounding a more resistant basaltic core. Throughout the valley, necks are preserved over a continuum of erosional sttges. A partially exhumed scoria cone near Cerro de Nuestra Senora represents one of the least eroded volcanoes, whereas all that remains of Cabezon Peak is the solidified magma core. Mantle and/or crustal xenoliths occur in about 60% of the necks. Cerros Guadalupe and Negro, in particular, contain an exceptional variety and abundance. A new whole-rock ~'Ari" Ar plateau age of 2.658 ± 0.032 Ma for Cabezon Peak is consistent with volcanism on the adjacent Mesa Chivato and Mesa Prieta. The two principal types of volcanic features in the Rio Puerco Valley are (I) subaerial volcanic centers 1hat produced surge and pyroclastic beds, lava flows and intrusive cores or crystallized lava lakes, and (2) wholly intrusive structures, such as dikes, which represent only a small part of the volcanic rocks in the valley. Based on field evidence, two models are given to explain the formation of the necks. In the first, a luff ring or scoria cone is built around a central vent, then magma ponds in the vent and solidifies. Later, erosion of the outer cone exposes the plug. This model is more consistent with the larger, more symmetrical necks, such as Cabezon Peak and Cerro de Nuestra Senora. In the second model, magma supply rates are lower, the volcanic cone and conduit smaller, and thermal retention lower. The necks form when small pods of magma intrude into overlying volcanic luffs and breccia near the waning stages of magmatic activity. Those that form by this process display irregular columnar jointing patterns. Most necks in the Rio Puerco Valley are consistent with this latter model.
里奥普尔科山谷的火山颈是世界上最集中、保存最完好的例子之一。它们是由固结不良的火山碎屑物质侵蚀形成的,这些物质围绕着一个更有抵抗力的玄武岩核心。在整个山谷中,颈部被保存在连续的侵蚀台阶上。在Cerro de Nuestra Senora附近,一个部分被挖掘出来的火山锥代表了一个被侵蚀最少的火山,而卡贝松峰的所有遗迹都是凝固的岩浆核心。地幔和/或地壳捕虏体出现在约60%的颈部。特别是瓜达卢佩山和内格罗山,有着非常丰富的品种。Cabezon峰新的全岩~ Ari”Ar高原年龄为2.658±0.032 Ma,与邻近的Mesa Chivato和Mesa Prieta的火山活动相一致。里奥普尔科山谷的两种主要火山特征是:(1)陆上火山中心1,产生涌浪和火山碎屑层、熔岩流和侵入岩心或结晶熔岩湖;(2)完全侵入的构造,如岩脉,仅占山谷中火山岩的一小部分。根据现场证据,给出了两种模型来解释颈的形成。首先,在一个中央喷口周围建立一个凸环或火山锥,然后岩浆在喷口中聚集并凝固。之后,外锥体的侵蚀暴露了塞。这种模式更符合更大、更对称的颈部,比如Cabezon Peak和Cerro de Nuestra Senora。在第二种模式下,岩浆供应速率较低,火山锥和导管较小,热潴留较低。当岩浆的小豆荚侵入上覆的火山隆起和角砾岩时,就形成了岩浆活动的减弱阶段。这些过程形成的节理显示不规则的柱状节理模式。里奥普尔科山谷的大多数脖子都符合后一种模式。
{"title":"Volcanic geology of the Rio Puerco necks","authors":"","doi":"10.56577/ffc-43.135","DOIUrl":"https://doi.org/10.56577/ffc-43.135","url":null,"abstract":"-The volcanic necks of the Rio Puerco Valley are among the most concentrated and best preserved examples in the world. They formed by erosion of poorly consolidated pyroclastic material surrounding a more resistant basaltic core. Throughout the valley, necks are preserved over a continuum of erosional sttges. A partially exhumed scoria cone near Cerro de Nuestra Senora represents one of the least eroded volcanoes, whereas all that remains of Cabezon Peak is the solidified magma core. Mantle and/or crustal xenoliths occur in about 60% of the necks. Cerros Guadalupe and Negro, in particular, contain an exceptional variety and abundance. A new whole-rock ~'Ari\" Ar plateau age of 2.658 ± 0.032 Ma for Cabezon Peak is consistent with volcanism on the adjacent Mesa Chivato and Mesa Prieta. The two principal types of volcanic features in the Rio Puerco Valley are (I) subaerial volcanic centers 1hat produced surge and pyroclastic beds, lava flows and intrusive cores or crystallized lava lakes, and (2) wholly intrusive structures, such as dikes, which represent only a small part of the volcanic rocks in the valley. Based on field evidence, two models are given to explain the formation of the necks. In the first, a luff ring or scoria cone is built around a central vent, then magma ponds in the vent and solidifies. Later, erosion of the outer cone exposes the plug. This model is more consistent with the larger, more symmetrical necks, such as Cabezon Peak and Cerro de Nuestra Senora. In the second model, magma supply rates are lower, the volcanic cone and conduit smaller, and thermal retention lower. The necks form when small pods of magma intrude into overlying volcanic luffs and breccia near the waning stages of magmatic activity. Those that form by this process display irregular columnar jointing patterns. Most necks in the Rio Puerco Valley are consistent with this latter model.","PeriodicalId":325871,"journal":{"name":"San Juan Basin IV","volume":"47 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131901548","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}
Regional gravity and magnetic maps that include the San Juan Basin area (e .g., Cordell, 1984: Keller and Cordell , 1984) demonstrate that there arc many significant anomalies present. Here , we present a series of re latively detailed maps that enhance these anomalies and briefly comment on the ir geological significance . Our primary goal is to present these maps for the use of those interested in this region and to illustrate their util ity. GRAVITY AND AEROMAGNETIC ANOMALY MAPS The geophysics group in the Department of Geological Sciences at The University of Texas at El Paso maintains an extensive database of gravity and magnetic measurements . These data were used to construct Bouguer gravity and total magnetic intensity anomaly maps of the San Juan Basin area. The San Juan Basin area contains more than 21,000 gravity and 17,000 magnetic data points. The data sets were processed to form a 2-km grid using a minimum curvature algorithm. A fi rst order polynomial surface was removed from both graips before they were filtered. The filtering algorithm employed was a general ized bandpass/strikepass fi lter based on the Hartley transform (Adams et al. , 1991 ). The maps were filtered to pass wavelengths from 20 km to 800 km . In addition, a gravity map was fi ltered to reject strikes from 85° to 225° east of north . These strikes are perpendicular to the prominent cast-northeast-trending gravity low that crosses the basin. The filtered gravity maps (Figs. I and 2) are dominated by maxima associated with basement uplifts. The Nacimiento and Zuni uplifts are of primary interest here. The northwest-trending gravity high associated with the Zuni uplift indicates that this feature is much larger than the actual Precambrian outcrop area . As di scussed by Woodward et al. (this volume), the Nac imiento upli ft and its bounding fau lts have been of interest for many years. The gravity maxima associated with this uplift correlate very well with the outcrop area. The steep gravity gradient FIGURE I . Residual gravity anomaly map, filtered to pass wavelengths from 20 to 800 km. on the west side of the uplift attests to the steep dip and large throw on th is fault. There is a distinct regional east-northeast grain in the gravity map shown in Fig . I. This trend correlates with the dominant anomaly in the aeromagnetic map discussed below. and gravity anomalies with this trend were enhanced to produce the map shown in Fig. 2. This map demonstrates the importance of Precambrian features, which reflect the evol ution of the crust in this region. The dominant feature on the aeromagnctic anomaly map (Fig . 3) is the northeast-trend ing low that extends across the San Juan Basin. passing just north of the Nacimiento uplift. Cordell and Keller ( 1984) showed that th is anomaly passes through the Rio Grande rift onto the Great Plai ns. This anomaly is offset as it crosses the rift and the Sangre de Cristo Mountai ns, indicating the presence of a series of right later
包括圣胡安盆地地区在内的区域重磁图(例如;, Cordell, 1984: Keller和Cordell, 1984)证明存在许多显著的异常。在这里,我们提出了一系列相对详细的地图,以加强这些异常,并简要评论其地质意义。我们的主要目标是提供这些地图供对该地区感兴趣的人使用,并说明它们的实用性。位于埃尔帕索的德克萨斯大学地质科学系的地球物理小组维护着一个广泛的重力和磁测量数据库。利用这些数据构建了圣胡安盆地地区的布格重磁和总磁异常图。圣胡安盆地地区包含超过21,000个重力数据点和17,000个磁数据点。使用最小曲率算法对数据集进行处理,形成一个2公里的网格。在对两幅图像进行过滤之前,先去除一阶多项式曲面。采用的滤波算法是基于Hartley变换的通用带通/走通滤波器(Adams et al., 1991)。这些地图经过过滤,波长从20公里到800公里。此外,对重力图进行了过滤,排除了北偏东85°至225°的走向。这些走向垂直于横贯盆地的突出的偏东北向重力低压。过滤后的重力图(图1)I和2)以与基底隆升相关的极大区为主。Nacimiento和Zuni隆起是这里的主要兴趣所在。与祖尼隆起相关的北西向重力高表明,该特征比实际的前寒武纪露头面积大得多。正如伍德沃德等人(本卷)所讨论的那样,多年来人们一直对南太平洋隆起及其边界断层感兴趣。与此隆起相关的重力最大值与露头区非常吻合。陡峭的重力梯度图1剩余重力异常图,过滤通过波长从20到800公里。在隆起的西侧,断层的倾角大,落差大。图中重力图呈现出明显的东北偏东的区域性纹理。这一趋势与下面讨论的航磁图中的优势异常有关。并对具有这种趋势的重力异常进行增强,生成图2所示的地图。这张地图显示了前寒武纪特征的重要性,反映了该地区地壳的演化。航磁异常图上的主导特征(图1)。3)是横跨圣胡安盆地的东北向低气压。正好经过纳西米恩托隆起的北部。Cordell和Keller(1984)表明该异常穿过b里约热内卢大裂谷进入大平原。该异常在穿过裂谷和圣克里斯多山脉时发生偏移,表明存在一系列右侧走向的唇状断层(Cordell和Keller, 1984)。它还遵循该地区前寒武纪基底的一般构造粒度(Grambling et al., 1988),并与Sangre de Cristo Mountains的Ortega群的露头大体相关。这种变质沉积岩的磁化率相对较低,因此这种负异常可能与较厚的变质沉积岩层序有关。Cordell和Grauch(1985)对圣胡安盆地地区的这一异常进行了复杂的分析,并绘制了一个东北向的表壳岩带,可能对应于图2。剩余重力异常图滤除波长为20 ~ 800 km,走行经滤除走行经85°~ 225°E。134凯勒和亚当斯
{"title":"Gravity and magneitc anomalies in the San Juan Basin area","authors":"G. Keller, D. Adams","doi":"10.56577/ffc-43.133","DOIUrl":"https://doi.org/10.56577/ffc-43.133","url":null,"abstract":"Regional gravity and magnetic maps that include the San Juan Basin area (e .g., Cordell, 1984: Keller and Cordell , 1984) demonstrate that there arc many significant anomalies present. Here , we present a series of re latively detailed maps that enhance these anomalies and briefly comment on the ir geological significance . Our primary goal is to present these maps for the use of those interested in this region and to illustrate their util ity. GRAVITY AND AEROMAGNETIC ANOMALY MAPS The geophysics group in the Department of Geological Sciences at The University of Texas at El Paso maintains an extensive database of gravity and magnetic measurements . These data were used to construct Bouguer gravity and total magnetic intensity anomaly maps of the San Juan Basin area. The San Juan Basin area contains more than 21,000 gravity and 17,000 magnetic data points. The data sets were processed to form a 2-km grid using a minimum curvature algorithm. A fi rst order polynomial surface was removed from both graips before they were filtered. The filtering algorithm employed was a general ized bandpass/strikepass fi lter based on the Hartley transform (Adams et al. , 1991 ). The maps were filtered to pass wavelengths from 20 km to 800 km . In addition, a gravity map was fi ltered to reject strikes from 85° to 225° east of north . These strikes are perpendicular to the prominent cast-northeast-trending gravity low that crosses the basin. The filtered gravity maps (Figs. I and 2) are dominated by maxima associated with basement uplifts. The Nacimiento and Zuni uplifts are of primary interest here. The northwest-trending gravity high associated with the Zuni uplift indicates that this feature is much larger than the actual Precambrian outcrop area . As di scussed by Woodward et al. (this volume), the Nac imiento upli ft and its bounding fau lts have been of interest for many years. The gravity maxima associated with this uplift correlate very well with the outcrop area. The steep gravity gradient FIGURE I . Residual gravity anomaly map, filtered to pass wavelengths from 20 to 800 km. on the west side of the uplift attests to the steep dip and large throw on th is fault. There is a distinct regional east-northeast grain in the gravity map shown in Fig . I. This trend correlates with the dominant anomaly in the aeromagnetic map discussed below. and gravity anomalies with this trend were enhanced to produce the map shown in Fig. 2. This map demonstrates the importance of Precambrian features, which reflect the evol ution of the crust in this region. The dominant feature on the aeromagnctic anomaly map (Fig . 3) is the northeast-trend ing low that extends across the San Juan Basin. passing just north of the Nacimiento uplift. Cordell and Keller ( 1984) showed that th is anomaly passes through the Rio Grande rift onto the Great Plai ns. This anomaly is offset as it crosses the rift and the Sangre de Cristo Mountai ns, indicating the presence of a series of right later","PeriodicalId":325871,"journal":{"name":"San Juan Basin IV","volume":"332 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133016755","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}
James H. Simpson , a lieutenant in the Army Corps of Topographical Engineers, reported the firs t extensive geo logica l observat ions of the San Juan Basin while accompanying the Wash ington Expedition against the Navajos in 1849. Simpson 's record of this C)(pedition also includes the first American descriptions of the Jemez Springs area, the ruins at Chaco Canyon, Canyon de Chcll y, and Inscripti on Rock (El Morro), as well as much information on the Hispanic, Pueblo and Navajo inhabitants of New Mexico shortly after it came under American control. He also named Washington Pass, in the southern Chuska Mountains, and Mount Taylor. This paper summarizes the day-to-day progress of the expedition. and di scusse, Simpson's geological observations and inte rpretations a long the route in the light of present knowledge of the geology of this area.
{"title":"James Hervey Simpson and the first record of San Juan Basin geology","authors":"B. Kues","doi":"10.56577/ffc-43.83","DOIUrl":"https://doi.org/10.56577/ffc-43.83","url":null,"abstract":"James H. Simpson , a lieutenant in the Army Corps of Topographical Engineers, reported the firs t extensive geo logica l observat ions of the San Juan Basin while accompanying the Wash ington Expedition against the Navajos in 1849. Simpson 's record of this C)(pedition also includes the first American descriptions of the Jemez Springs area, the ruins at Chaco Canyon, Canyon de Chcll y, and Inscripti on Rock (El Morro), as well as much information on the Hispanic, Pueblo and Navajo inhabitants of New Mexico shortly after it came under American control. He also named Washington Pass, in the southern Chuska Mountains, and Mount Taylor. This paper summarizes the day-to-day progress of the expedition. and di scusse, Simpson's geological observations and inte rpretations a long the route in the light of present knowledge of the geology of this area.","PeriodicalId":325871,"journal":{"name":"San Juan Basin IV","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116008953","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":"Ground-water resources of the southeastern San Juan Basin","authors":"W. Stone","doi":"10.56577/ffc-43.407","DOIUrl":"https://doi.org/10.56577/ffc-43.407","url":null,"abstract":"","PeriodicalId":325871,"journal":{"name":"San Juan Basin IV","volume":"61 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129712519","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}
~Triass ic strala in the Chama Basin and along the flanks of the Nacimiento and Jemez Mountains of Rio Arriba and Sandoval Counties, New Mexico , pertain to the Middle Triassic Moenkopi Formati on (Anton Chico Member) and the Upper Triassic Chinle Group (Agua Zarca, Sali tral , Poleo, Petrified Forest and Roc k Point Fomiations) . The Mocnko pi Formation is present only along the flanks of the Nacimiento and Jemez Mountains in Sandoval County. It is as much as 39 m thick and consists most ly of grayish red siltstone , mudstone and immature , trough-crossbedded sandstone. The Agua Zarca Formation is as much as 61 m thick and consists mostly of trough-crossbedded. q uartzose sandstone and siliceous conglomerate. Near Coyote in Rio Arriba County, it overlies " mott led strata" developed in the top of the Pennsy lvanian-Permian Cutler Form ation. The Salitral Formation is as much as 102 m of mostly purpl ish, smcct iti c mudstone. The Poleo Formation is up to 41 m thick and is mostly grayish ye llow, trough-crossbedded litharenites and subarkoses and minor amounts of both intrabasinal and siliceous conglomerate . Above the Poleo Formation , as much as 200 m of strata , dominated by reddi sh brown, smectitic mud stones, constitute the Petrifi ed Forest Formation . South of San Miguel Canyon in Sandoval County, the Poleo Format ion is not present. and all of the mudstonc sec tion above the Agua Zarca Formation is ass igned lo the Petrifi ed Forest Formation . Locally, near San Ysidro , the Correo Member is present at the top of the Pet rified Forest Formation. In the Chama physiographic bas in, the Rock Point Fom1a1ion, as much as 70 m thick and mostly reddish brown and gray ish red siltstone and ripplelaminar sandstone , disconformably overlies the Petrified Forest Formation. Three formations of the Chinle Group in north-central New Mexico contain biochronologically important fossils. notably the aetosaur Lonxosuch1u (late Camian) in the Salitral Formati on , the aetosaur Tvpothorax and the phytosaur Pseudopalatu.1· (early -middle Norian) in the Petrified Forest Formation, and a new genus of phytosaur (late Norian/Rhaet ian) in the Rock Point Formation. These foss ils and li thostratigraphy allow prec ise correlation of the Chinle Group strata exposed in north-central New Mexico with other Upper Triassic strata in New Mexico.
{"title":"Triassic stratigraphy and paleontology, Chama Basin and adjacent areas, north-central New Mexico","authors":"S. Lucas, A. Hunt","doi":"10.56577/ffc-43.151","DOIUrl":"https://doi.org/10.56577/ffc-43.151","url":null,"abstract":"~Triass ic strala in the Chama Basin and along the flanks of the Nacimiento and Jemez Mountains of Rio Arriba and Sandoval Counties, New Mexico , pertain to the Middle Triassic Moenkopi Formati on (Anton Chico Member) and the Upper Triassic Chinle Group (Agua Zarca, Sali tral , Poleo, Petrified Forest and Roc k Point Fomiations) . The Mocnko pi Formation is present only along the flanks of the Nacimiento and Jemez Mountains in Sandoval County. It is as much as 39 m thick and consists most ly of grayish red siltstone , mudstone and immature , trough-crossbedded sandstone. The Agua Zarca Formation is as much as 61 m thick and consists mostly of trough-crossbedded. q uartzose sandstone and siliceous conglomerate. Near Coyote in Rio Arriba County, it overlies \" mott led strata\" developed in the top of the Pennsy lvanian-Permian Cutler Form ation. The Salitral Formation is as much as 102 m of mostly purpl ish, smcct iti c mudstone. The Poleo Formation is up to 41 m thick and is mostly grayish ye llow, trough-crossbedded litharenites and subarkoses and minor amounts of both intrabasinal and siliceous conglomerate . Above the Poleo Formation , as much as 200 m of strata , dominated by reddi sh brown, smectitic mud stones, constitute the Petrifi ed Forest Formation . South of San Miguel Canyon in Sandoval County, the Poleo Format ion is not present. and all of the mudstonc sec tion above the Agua Zarca Formation is ass igned lo the Petrifi ed Forest Formation . Locally, near San Ysidro , the Correo Member is present at the top of the Pet rified Forest Formation. In the Chama physiographic bas in, the Rock Point Fom1a1ion, as much as 70 m thick and mostly reddish brown and gray ish red siltstone and ripplelaminar sandstone , disconformably overlies the Petrified Forest Formation. Three formations of the Chinle Group in north-central New Mexico contain biochronologically important fossils. notably the aetosaur Lonxosuch1u (late Camian) in the Salitral Formati on , the aetosaur Tvpothorax and the phytosaur Pseudopalatu.1· (early -middle Norian) in the Petrified Forest Formation, and a new genus of phytosaur (late Norian/Rhaet ian) in the Rock Point Formation. These foss ils and li thostratigraphy allow prec ise correlation of the Chinle Group strata exposed in north-central New Mexico with other Upper Triassic strata in New Mexico.","PeriodicalId":325871,"journal":{"name":"San Juan Basin IV","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129503625","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}