B. Sion, G. J. Axen, F. Phillips, Bruce J. Harrison
A bstrAct — The Rio Salado, southwest of Belen, is a large western tributary of the Rio Grande with a valley that is flanked by six major terrace levels. The presence of several Quaternary, rift-related normal faults and a mid-crustal magma layer beneath the Rio Salado valley provide an unusual opportunity to investigate the effects of various modes of tectonic deformation of the terraces. In this study, we mapped Rio Salado terraces using a commercial high-resolution DEM and digital color stereophotographs on a GIS workstation. The terraces were projected onto a vertical plane to construct longitudinal profiles. We employed the terrace nomenclature of existing 1:24,000-scale geologic maps, but divide Qte into two distinct terraces (Qte1 and Qte2). We estimated terrace ages of 346±123 ka (Qtg), 235±105 ka (Qtf), 160±86 ka (Qte1), 95±36 ka (Qtd), 52±39 ka (Qtc), and 7±5 ka (Qtb) using a net incision rate of 0.30±0.10 m/kyr, inferred from the correlation of Qte2 to the 122±18 ka Airport surface, ~25 km south of the Rio Salado valley. Terraces in the Loma Blanca fault (LBF) hanging wall are back-tilted relative to the footwall, suggesting a listric geometry for the LBF. Two exceptions are terrace levels Qtf and Qtc, which are east-tilted relative to their footwall counterparts. Both Qtf and Qtc merge eastward with the next youngest terrace in the flight. The Qtc terrace is arched, possibly reflecting surface uplift due to the Socorro magma body (SMB). Qtc is not offset by the LBF, suggesting that fault activity ceased in the valley prior to tread abandonment. This study is a preliminary report on the configuration and correlation of Rio Salado terraces. Future work will involve cosmogenic 36 Cl surface exposure dating to obtain a quantitative chronology for the Rio Salado terraces and enable the determination of incision rates and improve correlation with terraces regionally. Surface exposure dates will also provide constraints on slip rates of Quaternary faults and the geologic history of the SMB.
摘要:萨拉多河位于贝伦的西南部，是格兰德河西部的一条大支流，有一个山谷，两侧有六个主要的阶地。在里奥萨拉多山谷下，存在着几条第四纪与裂谷相关的正断层和一个地壳中岩浆层，这为研究各种构造变形模式对梯田的影响提供了一个不寻常的机会。在这项研究中，我们在GIS工作站上使用商业高分辨率DEM和数字彩色立体照片绘制了里约萨拉多梯田。露台被投射到一个垂直平面上，以构建纵向剖面。我们采用现有1:24 000比例尺地质图的阶地命名法，但将Qte划分为两个不同的阶地(Qte1和Qte2)。根据Qte2与Rio Salado河谷以南约25 km的机场面(122±18 ka)的相关性，利用0.30±0.10 m/kyr的净切口率，我们估计阶地年龄为346±123 ka (Qtg)、235±105 ka (Qtf)、160±86 ka (Qte1)、95±36 ka (Qtd)、52±39 ka (Qtc)和7±5 ka (Qtb)。洛马布兰卡断层(LBF)上盘的阶地相对于下盘是向后倾斜的，这表明LBF的几何形状是扁平的。两个例外是阶地水平Qtf和Qtc，它们相对于下盘水平向东倾斜。Qtf和Qtc都与下一个最年轻的露台向东合并。Qtc阶地呈拱形，可能反映了Socorro岩浆体(SMB)引起的地表隆起。Qtc没有被LBF抵消，这表明在踏面放弃之前，山谷中的断层活动已经停止。本研究是对里奥萨拉多阶地的构造和对比的初步研究。未来的工作将涉及宇宙成因36 Cl表面暴露定年，以获得里约萨拉多阶地的定量年表，并确定切口率，并改善与区域阶地的相关性。地表暴露日期也将为第四纪断层的滑动速率和SMB的地质历史提供约束。
{"title":"Fluvial terraces in the lower Rio Salado valley: correlations, estimated ages, and implications for Quaternary faulting and for surface uplift above the Socorro Magma Body","authors":"B. Sion, G. J. Axen, F. Phillips, Bruce J. Harrison","doi":"10.56577/ffc-.235","DOIUrl":"https://doi.org/10.56577/ffc-.235","url":null,"abstract":"A bstrAct — The Rio Salado, southwest of Belen, is a large western tributary of the Rio Grande with a valley that is flanked by six major terrace levels. The presence of several Quaternary, rift-related normal faults and a mid-crustal magma layer beneath the Rio Salado valley provide an unusual opportunity to investigate the effects of various modes of tectonic deformation of the terraces. In this study, we mapped Rio Salado terraces using a commercial high-resolution DEM and digital color stereophotographs on a GIS workstation. The terraces were projected onto a vertical plane to construct longitudinal profiles. We employed the terrace nomenclature of existing 1:24,000-scale geologic maps, but divide Qte into two distinct terraces (Qte1 and Qte2). We estimated terrace ages of 346±123 ka (Qtg), 235±105 ka (Qtf), 160±86 ka (Qte1), 95±36 ka (Qtd), 52±39 ka (Qtc), and 7±5 ka (Qtb) using a net incision rate of 0.30±0.10 m/kyr, inferred from the correlation of Qte2 to the 122±18 ka Airport surface, ~25 km south of the Rio Salado valley. Terraces in the Loma Blanca fault (LBF) hanging wall are back-tilted relative to the footwall, suggesting a listric geometry for the LBF. Two exceptions are terrace levels Qtf and Qtc, which are east-tilted relative to their footwall counterparts. Both Qtf and Qtc merge eastward with the next youngest terrace in the flight. The Qtc terrace is arched, possibly reflecting surface uplift due to the Socorro magma body (SMB). Qtc is not offset by the LBF, suggesting that fault activity ceased in the valley prior to tread abandonment. This study is a preliminary report on the configuration and correlation of Rio Salado terraces. Future work will involve cosmogenic 36 Cl surface exposure dating to obtain a quantitative chronology for the Rio Salado terraces and enable the determination of incision rates and improve correlation with terraces regionally. Surface exposure dates will also provide constraints on slip rates of Quaternary faults and the geologic history of the SMB.","PeriodicalId":243410,"journal":{"name":"Guidebook 67 - Geology of the Belen Area","volume":"10 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":"131972523","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}
Widely scattered coal and clinker clasts and flotsam, combined with historical photos, and modern observations in the lower Abo Arroyo indicate valley-wide flooding and significant changes in sediment transport and channel erosion during the 20th Century. Coal and clinker granules and pebbles (2to 40-mm diameter) as well as flotsam of whole juniper trees and other wooden debris along the valley floor of Abo Arroyo show that the valley was inundated by one or more large floods. Aerial photos taken in 1935 show widespread dark deposits along the valley floor. These dark deposits are believed to be coal that came from spills along the Atchison, Topeka and Santa Fe (AT&SF) Railroad through Abo Pass to the east. The railroad was built between 1903 and 1908, when the first timetable for the route was published. Prior to 1935, the most likely period for extensive flooding was in August and September of 1929, when regional storms and flooding occurred on the Rio Puerco, Rio Grande, and other gauged tributaries. The 1935 photographs also show that the lower 10 km of Abo valley had anastomosing unincised channels, gravel bars, and slackwater yazoos along the valley margins. No continuous incised channel existed, although branching short headcuts extended from the arroyo mouth at the Rio Grande, upstream about 2 km, across the valley-mouth Holocene alluvial fan. Aerial photographs taken in 1947 show that channel incision along the valley floor farther east had increased downstream and that much of the coal had been remobilized, reworked, and partially buried by later flood deposits. The lowest reach of Abo Arroyo became entrenched by 1954, completing a continuous channel from Abo Canyon westward. Incision by headcutting was, at most, a minor process at the arroyo mouth. This channel behavior along lower Abo valley is unlike most other arroyos in New Mexico because: 1) Abo Arroyo was not incised continuously well into the 20th Century, 2) due to concentration and then dispersion of stream power it incised downstream rather than upstream, 3) it is a bedload stream with a gradient three to seven times steeper than adjacent streams (Rio Grande and Rio Puerco), 4) adjacent sparse vegetation has minimal effect on flows, and 5) it is not evolving (so far) through stages of arroyo development and aggradation. 447
{"title":"Uncommon twentieth-century stream behavior of lower Abo Arroyo revealed by flood deposits and historic photographs","authors":"D. Love, A. Rinehart","doi":"10.56577/ffc-.447","DOIUrl":"https://doi.org/10.56577/ffc-.447","url":null,"abstract":"Widely scattered coal and clinker clasts and flotsam, combined with historical photos, and modern observations in the lower Abo Arroyo indicate valley-wide flooding and significant changes in sediment transport and channel erosion during the 20th Century. Coal and clinker granules and pebbles (2to 40-mm diameter) as well as flotsam of whole juniper trees and other wooden debris along the valley floor of Abo Arroyo show that the valley was inundated by one or more large floods. Aerial photos taken in 1935 show widespread dark deposits along the valley floor. These dark deposits are believed to be coal that came from spills along the Atchison, Topeka and Santa Fe (AT&SF) Railroad through Abo Pass to the east. The railroad was built between 1903 and 1908, when the first timetable for the route was published. Prior to 1935, the most likely period for extensive flooding was in August and September of 1929, when regional storms and flooding occurred on the Rio Puerco, Rio Grande, and other gauged tributaries. The 1935 photographs also show that the lower 10 km of Abo valley had anastomosing unincised channels, gravel bars, and slackwater yazoos along the valley margins. No continuous incised channel existed, although branching short headcuts extended from the arroyo mouth at the Rio Grande, upstream about 2 km, across the valley-mouth Holocene alluvial fan. Aerial photographs taken in 1947 show that channel incision along the valley floor farther east had increased downstream and that much of the coal had been remobilized, reworked, and partially buried by later flood deposits. The lowest reach of Abo Arroyo became entrenched by 1954, completing a continuous channel from Abo Canyon westward. Incision by headcutting was, at most, a minor process at the arroyo mouth. This channel behavior along lower Abo valley is unlike most other arroyos in New Mexico because: 1) Abo Arroyo was not incised continuously well into the 20th Century, 2) due to concentration and then dispersion of stream power it incised downstream rather than upstream, 3) it is a bedload stream with a gradient three to seven times steeper than adjacent streams (Rio Grande and Rio Puerco), 4) adjacent sparse vegetation has minimal effect on flows, and 5) it is not evolving (so far) through stages of arroyo development and aggradation. 447","PeriodicalId":243410,"journal":{"name":"Guidebook 67 - Geology of the Belen Area","volume":"11 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":"134502931","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":"Pennsylvanian strata in the Los Pinos Mountains","authors":"B. Allen, S. Lucas, K. Krainer, D. Love","doi":"10.56577/ffc-.33","DOIUrl":"https://doi.org/10.56577/ffc-.33","url":null,"abstract":"","PeriodicalId":243410,"journal":{"name":"Guidebook 67 - Geology of the Belen Area","volume":"37 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":"134364083","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":"Cleanup of petroleum contaminated soil at the former Midway grocery gasoline station in Jarales, New Mexico","authors":"S. Von Gonten, M. D. McVey, Gundar Peterson","doi":"10.56577/ffc-.95","DOIUrl":"https://doi.org/10.56577/ffc-.95","url":null,"abstract":"","PeriodicalId":243410,"journal":{"name":"Guidebook 67 - Geology of the Belen Area","volume":"31 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":"115528114","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}
N. Dunbar, W. Mcintosh, D. Love, K. Panter, B. Hallett
A study of 86 samples of trachyandesitic and dacitic lava and cinders from the Los Lunas volcano, central New Mexico, demonstrates the volcano consists of two overlapping but temporally and compositionally distinct eruptive edifices differing in age by 2.56 Ma. Lava compositions at Los Lunas volcano are consistent with other lavas found in the Rio Grande rift, but, based on major and trace element determinations, no simple model can be proposed to genetically link the two dominant magma compositions. Rather, the two magma batches appear to have been independently generated, consistent with the large age gap between eruptions of the two edifices. An experiment carried out as part of this study indicates that the accuracy and precision of 40Ar/39Ar dates for young mafic to intermediate lavas can be maximized by selecting samples that contain K-feldspar as a late-crystallized phase, and contain little or no glass or alteration phases. Characterization of samples was undertaken using the electron microprobe, where samples were ranked on a scale of 1 to 10 (with 10 being most suitable for dating) based largely on whether the K in the sample could be determined to be housed in extremely fine-grained feldspar interstitial to more abundant phenocryst phases, or was in residual volcanic glass. Sample rating was downgraded if the sample showed evidence of chemical alteration. The 40Ar/39Ar results from the most highly rated samples yield an age of 3.83±0.05 Ma for the Southwest Edifice of Los Lunas volcano. This volcanic center is physically overlapped by the 1.271±0.014 Ma Main Edifice. The absolute ages agree with relative ages determined from geological mapping. Within the Main Edifice, field relationships indicate a sequence of five eruptive events. The ages of the best samples from the Main Edifice all agree within analytical error, suggesting that the entire period of eruptive activity spanned less than 100,000 years. The precision and accuracy of data in this study were much enhanced by using microprobe observations of groundmass glass and K-feldspar to aid in the sample selection process. Sample selection based only on thin section observations would have yielded lower quality data, because the degree of crystallization of residual glass would have been incompletely assessed. 203
{"title":"Two eruptive episodes of Los Lunas Volcano: geochemistry and 40Ar/39Ar age determination using electron microprobe sample evaluation","authors":"N. Dunbar, W. Mcintosh, D. Love, K. Panter, B. Hallett","doi":"10.56577/ffc-.203","DOIUrl":"https://doi.org/10.56577/ffc-.203","url":null,"abstract":"A study of 86 samples of trachyandesitic and dacitic lava and cinders from the Los Lunas volcano, central New Mexico, demonstrates the volcano consists of two overlapping but temporally and compositionally distinct eruptive edifices differing in age by 2.56 Ma. Lava compositions at Los Lunas volcano are consistent with other lavas found in the Rio Grande rift, but, based on major and trace element determinations, no simple model can be proposed to genetically link the two dominant magma compositions. Rather, the two magma batches appear to have been independently generated, consistent with the large age gap between eruptions of the two edifices. An experiment carried out as part of this study indicates that the accuracy and precision of 40Ar/39Ar dates for young mafic to intermediate lavas can be maximized by selecting samples that contain K-feldspar as a late-crystallized phase, and contain little or no glass or alteration phases. Characterization of samples was undertaken using the electron microprobe, where samples were ranked on a scale of 1 to 10 (with 10 being most suitable for dating) based largely on whether the K in the sample could be determined to be housed in extremely fine-grained feldspar interstitial to more abundant phenocryst phases, or was in residual volcanic glass. Sample rating was downgraded if the sample showed evidence of chemical alteration. The 40Ar/39Ar results from the most highly rated samples yield an age of 3.83±0.05 Ma for the Southwest Edifice of Los Lunas volcano. This volcanic center is physically overlapped by the 1.271±0.014 Ma Main Edifice. The absolute ages agree with relative ages determined from geological mapping. Within the Main Edifice, field relationships indicate a sequence of five eruptive events. The ages of the best samples from the Main Edifice all agree within analytical error, suggesting that the entire period of eruptive activity spanned less than 100,000 years. The precision and accuracy of data in this study were much enhanced by using microprobe observations of groundmass glass and K-feldspar to aid in the sample selection process. Sample selection based only on thin section observations would have yielded lower quality data, because the degree of crystallization of residual glass would have been incompletely assessed. 203","PeriodicalId":243410,"journal":{"name":"Guidebook 67 - Geology of the Belen Area","volume":"39 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":"122728316","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}
V. Blomgren, Amy Williams, L. Crossey, K. Karlstrom, F. Goff
Understanding groundwater resources in the Albuquerque basin region requires an understanding of the geochemistry of carbonic springs and potential mixing among different water sources. Carbonic springs are defined as high PCO2 springs (PCO2 >10-1.8). This paper evaluates the sources of the high dissolved CO2 in these springs by summarizing the geochemistry of carbonic springs found along faults of the Rio Grande rift. Major ion chemistry helps define chemical characteristics of endogenic (deeply sourced) fluids entering the groundwater system and their variable mixing with epigenic waters (meteoric recharge). We also use major ion water chemistry analyses to estimate the percentage of CO2 derived from dissolution of carbonates (both rock and minerals) (Ccarb) in groundwater. We then use carbon isotopes to estimate the percentage of the remaining external CO2 (Cext) that was derived from organic material such as soil gas (Corg) plus endogenic CO2 that is from deeply derived sources (Cendo). The results show a high percentage of endogenic components in the west flank of the Rio Grande rift spring waters with a range of 17.5 74.8% Cendo (mean value of 55.3%±19.8%). We analyzed dissolved gases to illustrate a spectrum of mixing between air and air-saturated groundwater with helium-rich deeply sourced fluids. The high endogenic CO2 in springs and travertines that occur within the Rio Grande rift at San Acacia and along much of the western rift faults from Socorro to I-40 is interpreted to reflect degassing of magmatic volatiles from the Socorro magma body. The wide distribution of springs suggests that similar waters may be cryptically entering Santa Fe Group aquifers from below and affecting water quality by adding salinity and trace metals as well as deeply sourced volatiles. These endogenic inputs are tepid (up to 26°C) and have geochemical similarities to geothermal waters. The variation in hydrochemistry of the Albuquerque basin can be attributed in part to mixing of endogenic fluids with other groundwater and has implications for future management of groundwater resources. 419
{"title":"Identifying the sources of CO2 in carbonic springs in the Albuquerque-Belen Basin","authors":"V. Blomgren, Amy Williams, L. Crossey, K. Karlstrom, F. Goff","doi":"10.56577/ffc-.419","DOIUrl":"https://doi.org/10.56577/ffc-.419","url":null,"abstract":"Understanding groundwater resources in the Albuquerque basin region requires an understanding of the geochemistry of carbonic springs and potential mixing among different water sources. Carbonic springs are defined as high PCO2 springs (PCO2 >10-1.8). This paper evaluates the sources of the high dissolved CO2 in these springs by summarizing the geochemistry of carbonic springs found along faults of the Rio Grande rift. Major ion chemistry helps define chemical characteristics of endogenic (deeply sourced) fluids entering the groundwater system and their variable mixing with epigenic waters (meteoric recharge). We also use major ion water chemistry analyses to estimate the percentage of CO2 derived from dissolution of carbonates (both rock and minerals) (Ccarb) in groundwater. We then use carbon isotopes to estimate the percentage of the remaining external CO2 (Cext) that was derived from organic material such as soil gas (Corg) plus endogenic CO2 that is from deeply derived sources (Cendo). The results show a high percentage of endogenic components in the west flank of the Rio Grande rift spring waters with a range of 17.5 74.8% Cendo (mean value of 55.3%±19.8%). We analyzed dissolved gases to illustrate a spectrum of mixing between air and air-saturated groundwater with helium-rich deeply sourced fluids. The high endogenic CO2 in springs and travertines that occur within the Rio Grande rift at San Acacia and along much of the western rift faults from Socorro to I-40 is interpreted to reflect degassing of magmatic volatiles from the Socorro magma body. The wide distribution of springs suggests that similar waters may be cryptically entering Santa Fe Group aquifers from below and affecting water quality by adding salinity and trace metals as well as deeply sourced volatiles. These endogenic inputs are tepid (up to 26°C) and have geochemical similarities to geothermal waters. The variation in hydrochemistry of the Albuquerque basin can be attributed in part to mixing of endogenic fluids with other groundwater and has implications for future management of groundwater resources. 419","PeriodicalId":243410,"journal":{"name":"Guidebook 67 - Geology of the Belen Area","volume":"1995 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":"128175975","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}
Small, uneconomic, stratabound sedimentary-copper deposits at the Scholle mining district are restricted predominantly to the lower member of the Abo Formation, with minor occurrences in the upper member of the Bursum Formation and the Meseta Blanca Sandstone Member of the Yeso Formation. Spanish settlers likely mined copper from the district sometime after the founding of the Abo and other Salinas missions in the area in 1629. Sedimentary-copper deposits were rediscovered by modern prospectors in the Scholle district as early as 1902, but production did not begin until 1915. From 1915 to 1961, 15,037 short tons of ore were produced and yielded 1,122,468 lbs Cu, 8,147 oz Ag, and 426 lbs Pb. Copper and uranium minerals in the Abo Formation occur: (1) as disseminations within bleached arkose, limestone-pebble conglomerate and siltstone; (2) along bedding planes and fractures at or near sandstone-shale, sandstone-siltstone and sandstone-limestone contacts; (3) as replacements of wood and other organic materials; and (4) as replacements of clay or calcite cement within the host sandstone. Copper and other metals were probably transported in low-temperature brine solutions through permeable sediments and along bedding planes and faults shortly after burial. Oxidizing waters could have leached copper and other metals from at least three sources: (1) clay minerals and detrital mineral grains and rock fragments within the red-bed sequences, (2) Proterozoic rocks enriched in these metals, and (3) Proterozoic base-metal deposits. Most sedimentary-copper deposits in the Scholle district, as elsewhere in New Mexico, are too low grade, low tonnage, and far from existing copper mills for current development of copper. However, increases in copper and silver prices have sporadically renewed interest in some of the larger deposits, such as in the Scholle district. 249
{"title":"Geology and mineral deposits of the sedimentary-copper deposits in the Scholle Mining District, Socorro, Torrance and Valencia counties, New Mexico","authors":"V. McLemore","doi":"10.56577/ffc-.249","DOIUrl":"https://doi.org/10.56577/ffc-.249","url":null,"abstract":"Small, uneconomic, stratabound sedimentary-copper deposits at the Scholle mining district are restricted predominantly to the lower member of the Abo Formation, with minor occurrences in the upper member of the Bursum Formation and the Meseta Blanca Sandstone Member of the Yeso Formation. Spanish settlers likely mined copper from the district sometime after the founding of the Abo and other Salinas missions in the area in 1629. Sedimentary-copper deposits were rediscovered by modern prospectors in the Scholle district as early as 1902, but production did not begin until 1915. From 1915 to 1961, 15,037 short tons of ore were produced and yielded 1,122,468 lbs Cu, 8,147 oz Ag, and 426 lbs Pb. Copper and uranium minerals in the Abo Formation occur: (1) as disseminations within bleached arkose, limestone-pebble conglomerate and siltstone; (2) along bedding planes and fractures at or near sandstone-shale, sandstone-siltstone and sandstone-limestone contacts; (3) as replacements of wood and other organic materials; and (4) as replacements of clay or calcite cement within the host sandstone. Copper and other metals were probably transported in low-temperature brine solutions through permeable sediments and along bedding planes and faults shortly after burial. Oxidizing waters could have leached copper and other metals from at least three sources: (1) clay minerals and detrital mineral grains and rock fragments within the red-bed sequences, (2) Proterozoic rocks enriched in these metals, and (3) Proterozoic base-metal deposits. Most sedimentary-copper deposits in the Scholle district, as elsewhere in New Mexico, are too low grade, low tonnage, and far from existing copper mills for current development of copper. However, increases in copper and silver prices have sporadically renewed interest in some of the larger deposits, such as in the Scholle district. 249","PeriodicalId":243410,"journal":{"name":"Guidebook 67 - Geology of the Belen Area","volume":"22 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":"130240018","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}
This manuscript highlights several processes that may have been influential in the development of the Rio Grande rift by reviewing important results from recent studies. In the Albuquerque Basin, low-angle normal faults exist in several locations, but are discontinuously preserved and generally offset and rotated by high-angle normal faults. The Sandia and Sierra Ladrones rift flank uplifts, which are the highest elevation rift flanks on opposite sides of the Albuquerque Basin, both have low-angle normal faults, have maximum extension in the Albuquerque Basin, show fault dips that increase from the rift margin towards the axis of the basin, and show fault ages that young towards the center of the basin. Thermochronologic data suggest that both of these rift flanks were exhumed at nearly the same time, 10-25 Ma. These observations suggest a rolling-hinge mechanism for the formation of low-angle normal faults in the Rio Grande rift, where isostatic uplift appears to be a dominant process in regions of maximum extension. This process can therefore dramatically affect basin and rift-flank geometry as rifting progresses and suggests that the Sandia and Ladron uplifts are moderate-extension analogs to core complexes. To further understand extensional processes and timing of extension within the Rio Grande rift, apatite fission-track (AFT) and apatite (U-Th)/He thermochronologic methods were used to produce thermal history models from Rio Grande rift flank uplifts in Colorado and New Mexico. These models indicate that extension along the majority of the length of the rift was synchronous from 10-25 Ma. Existing geodynamic models for rift formation such as collapse of high topography or reduction of far field stresses due to growth of the San Andreas transform, or reactivation of older weaknesses, may not adequately explain the simultaneous 10-25 Ma opening of the Rio Grande rift from Colorado to Texas, nor explicitly link rifting to prior events such as the ignimbrite flare-up and Laramide orogeny. A model is therefore favored that involves Laramide flexure of the downgoing Farallon plate at the eastern Rocky Mountain front, delamination of sections of the Farallon Plate beneath the San Juan and Mogollon Datil volcanic fields to initiate and explain migrations of volcanism in the ignimbrite flare up, then a “big break” and foundering of the Farallon plate beneath the Rio Grande rift at ca. 25-30 Ma. This event focused asthenospheric upwelling along a north-south trend, weakening the overlying North American lithosphere and facilitating E-W extension from Colorado to southern New Mexico. 195
{"title":"Processes controlling the development of the Rio Grande Rift at long timescales","authors":"J. Ricketts, K. Karlstrom, M. Heizler","doi":"10.56577/ffc-.195","DOIUrl":"https://doi.org/10.56577/ffc-.195","url":null,"abstract":"This manuscript highlights several processes that may have been influential in the development of the Rio Grande rift by reviewing important results from recent studies. In the Albuquerque Basin, low-angle normal faults exist in several locations, but are discontinuously preserved and generally offset and rotated by high-angle normal faults. The Sandia and Sierra Ladrones rift flank uplifts, which are the highest elevation rift flanks on opposite sides of the Albuquerque Basin, both have low-angle normal faults, have maximum extension in the Albuquerque Basin, show fault dips that increase from the rift margin towards the axis of the basin, and show fault ages that young towards the center of the basin. Thermochronologic data suggest that both of these rift flanks were exhumed at nearly the same time, 10-25 Ma. These observations suggest a rolling-hinge mechanism for the formation of low-angle normal faults in the Rio Grande rift, where isostatic uplift appears to be a dominant process in regions of maximum extension. This process can therefore dramatically affect basin and rift-flank geometry as rifting progresses and suggests that the Sandia and Ladron uplifts are moderate-extension analogs to core complexes. To further understand extensional processes and timing of extension within the Rio Grande rift, apatite fission-track (AFT) and apatite (U-Th)/He thermochronologic methods were used to produce thermal history models from Rio Grande rift flank uplifts in Colorado and New Mexico. These models indicate that extension along the majority of the length of the rift was synchronous from 10-25 Ma. Existing geodynamic models for rift formation such as collapse of high topography or reduction of far field stresses due to growth of the San Andreas transform, or reactivation of older weaknesses, may not adequately explain the simultaneous 10-25 Ma opening of the Rio Grande rift from Colorado to Texas, nor explicitly link rifting to prior events such as the ignimbrite flare-up and Laramide orogeny. A model is therefore favored that involves Laramide flexure of the downgoing Farallon plate at the eastern Rocky Mountain front, delamination of sections of the Farallon Plate beneath the San Juan and Mogollon Datil volcanic fields to initiate and explain migrations of volcanism in the ignimbrite flare up, then a “big break” and foundering of the Farallon plate beneath the Rio Grande rift at ca. 25-30 Ma. This event focused asthenospheric upwelling along a north-south trend, weakening the overlying North American lithosphere and facilitating E-W extension from Colorado to southern New Mexico. 195","PeriodicalId":243410,"journal":{"name":"Guidebook 67 - Geology of the Belen Area","volume":"97 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":"122785319","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}
S. Lucas, K. Krainer, C. Oviatt, D. Vachard, D. Berman, A. Henrici
The Permian stratigraphic section at Abo Pass at the southern tip of the Manzano Mountains (Torrance, Valencia and Socorro Counties, New Mexico) is ~800 m thick and is assigned to the (ascending order): Bursum Formation (Red Tanks Member), Abo Formation (Scholle and Cañon de Espinoso members), Yeso Group (Arroyo del Alamillo Formation and overlying Los Vallos Formation divided into Torres, Cañas and Joyita members), Glorieta Sandstone and San Andres Formation. The Bursum Formation is ~35-40 m thick and consists of interbedded red-bed siliciclastics (mudstone, sandstone and conglomerate) and marine limestones. The Abo Formation is ~310 m thick and consists of siliciclastic red beds divided into the Scholle Member (~140 m of mudstone with channelized beds of crossbedded sandstone and conglomerate) overlain by the Cañon de Espinoso Member (~170 m of mudstone, siltstone and many thin beds of sandstone that display climbing ripple lamination). The lower formation of the Yeso Group, the Arroyo de Alamillo Formation, consisting of ~80 m of red-bed sandstone (mostly ripple and laminar with some gypsiferous beds) and very minor dolomite. The overlying Torres Member of the Los Vallos Formation is ~180 m thick and consists of mostly gypsiferous siltstone, claystone, gypsum and a few prominent beds of dolomite and gypsiferous sandstone. The overlying Cañas Member is 16-52 m thick, consisting mostly of gypsum and includes a few beds of gypsiferous siltstone and dolomite. The Joyita Member is ~21 m thick and consists of red-bed sandstone that is crossbedded, ripple laminated and, in some beds, gypsiferous. The Glorieta Sandstone is ~78 m thick and consists of crossbedded, laminar and ripple laminar quartzose sandstone. In the Abo Pass area, the upper part of the San Andres Formation has been eroded, leaving up to 91 m of mostly limestone (lime mudstone). It is overlain by Triassic strata east of the Abo Pass area. Bursum deposition took place in a mixture of nonmarine fluvial and shallow marine depositional environments in a tectonically active, mostly coastal setting. Rivers that deposited the Abo Formation formed extensive muddy floodplains traversed by incised rivers early in Abo deposition that later gave way to extensive sheetflooding. Yeso sedimentation began with dominantly eolian deposition on an arid coastal plain (Arroyo de Alamillo Formation) followed by deposits of coastal sabkhas, dunes and restricted marine embayments (Torres and Cañas members of Los Vallos Formation). Yeso sedimentation ended with the Joyita Member of the Los Vallos Formation, which formed by eolian and fluvial processes during lowered sea level. The Glorieta Sandstone is mostly of eolian origin, and the San Andres Formation represents shallow marine deposits. Fusulinids from the Bursum Formation at Abo Pass indicate it is early Wolfcampian in age. The Abo Formation at Abo Pass yields fossil plants, tetrapod tracks and other trace fossils, as well as vertebrate fossils of Coyote
位于Manzano山脉南端(新墨西哥州Torrance、Valencia和Socorro县)的Abo Pass二叠系地层剖面厚度约800 m，划分为(从高到低):Bursum组(Red Tanks组)、Abo组(Scholle和Cañon de Espinoso组)、Yeso组(Arroyo del Alamillo组和上覆的Los Vallos组分为Torres、Cañas和Joyita组)、Glorieta砂岩和San Andres组。Bursum组厚度约35 ~ 40 m，由红层硅质(泥岩、砂岩和砾岩)和海相灰岩互层组成。Abo组厚度约310 m，由硅屑红层组成，分为Scholle段(~140 m泥岩，具有交错砂岩和砾岩的河道化层)和Cañon de Espinoso段(~170 m泥岩、粉砂岩和许多薄砂岩层，具有上升的波纹层状)。Yeso群下部的Arroyo de Alamillo组，由~80 m的红层砂岩(主要是波纹层和层状层，有一些石膏质层)和少量白云岩组成。上覆的洛斯瓦洛斯组托雷斯段厚度约180 m，主要由石膏质粉砂岩、粘土岩、石膏和少数突出的白云岩和石膏质砂岩层组成。上覆的Cañas段厚度为16-52 m，主要由石膏组成，包括几层石膏粉砂岩和白云岩。乔伊塔段厚约21米，由交错层状、波纹层状的红层砂岩组成，某些层状为石膏质砂岩。格洛列塔砂岩厚度约78 m，由交错层状、层状和波纹层状石英砂岩组成。在阿博山口地区，圣安德烈斯组的上部已被侵蚀，留下长达91米的石灰岩(石灰泥岩)。其上覆有阿波山口以东的三叠系地层。Bursum沉积发生在非海相河流和浅海沉积环境的混合环境中，构造活跃，主要是沿海环境。沉积Abo组的河流在Abo沉积早期形成了广泛的泥质洪泛平原，被切割的河流穿过，后来被广泛的薄片洪水所取代。Yeso沉积始于干旱沿海平原(Arroyo de Alamillo组)的主要风成沉积，随后是沿海sabkhas，沙丘和限制性海洋海湾(Torres和Cañas Los Vallos组成员)的沉积。耶索沉积结束于洛斯瓦洛斯组乔伊伊塔段，这是在海平面下降期间由风成和河流作用形成的。格洛列塔砂岩主要为风成砂岩，圣安德烈斯组为浅海沉积。阿波山口布尔萨姆组的褐藻质特征表明其年龄为狼世早期。在阿博山口的阿博组发现了植物化石、四足动物的足迹和其他痕迹化石，以及土狼时代的脊椎动物化石。来自Yeso群，gloria砂岩和San Andres组的微化石包含了两个新物种，Velebitella americana和Calcitornella interpsammica。当地古生物资料结合区域对比表明，Abo组为狼世中期至列奥纳第早期，格洛列塔组和圣安德烈斯组为列奥纳第晚期。313
{"title":"The Permian system at Abo Pass, central New Mexico (USA)","authors":"S. Lucas, K. Krainer, C. Oviatt, D. Vachard, D. Berman, A. Henrici","doi":"10.56577/ffc-.313","DOIUrl":"https://doi.org/10.56577/ffc-.313","url":null,"abstract":"The Permian stratigraphic section at Abo Pass at the southern tip of the Manzano Mountains (Torrance, Valencia and Socorro Counties, New Mexico) is ~800 m thick and is assigned to the (ascending order): Bursum Formation (Red Tanks Member), Abo Formation (Scholle and Cañon de Espinoso members), Yeso Group (Arroyo del Alamillo Formation and overlying Los Vallos Formation divided into Torres, Cañas and Joyita members), Glorieta Sandstone and San Andres Formation. The Bursum Formation is ~35-40 m thick and consists of interbedded red-bed siliciclastics (mudstone, sandstone and conglomerate) and marine limestones. The Abo Formation is ~310 m thick and consists of siliciclastic red beds divided into the Scholle Member (~140 m of mudstone with channelized beds of crossbedded sandstone and conglomerate) overlain by the Cañon de Espinoso Member (~170 m of mudstone, siltstone and many thin beds of sandstone that display climbing ripple lamination). The lower formation of the Yeso Group, the Arroyo de Alamillo Formation, consisting of ~80 m of red-bed sandstone (mostly ripple and laminar with some gypsiferous beds) and very minor dolomite. The overlying Torres Member of the Los Vallos Formation is ~180 m thick and consists of mostly gypsiferous siltstone, claystone, gypsum and a few prominent beds of dolomite and gypsiferous sandstone. The overlying Cañas Member is 16-52 m thick, consisting mostly of gypsum and includes a few beds of gypsiferous siltstone and dolomite. The Joyita Member is ~21 m thick and consists of red-bed sandstone that is crossbedded, ripple laminated and, in some beds, gypsiferous. The Glorieta Sandstone is ~78 m thick and consists of crossbedded, laminar and ripple laminar quartzose sandstone. In the Abo Pass area, the upper part of the San Andres Formation has been eroded, leaving up to 91 m of mostly limestone (lime mudstone). It is overlain by Triassic strata east of the Abo Pass area. Bursum deposition took place in a mixture of nonmarine fluvial and shallow marine depositional environments in a tectonically active, mostly coastal setting. Rivers that deposited the Abo Formation formed extensive muddy floodplains traversed by incised rivers early in Abo deposition that later gave way to extensive sheetflooding. Yeso sedimentation began with dominantly eolian deposition on an arid coastal plain (Arroyo de Alamillo Formation) followed by deposits of coastal sabkhas, dunes and restricted marine embayments (Torres and Cañas members of Los Vallos Formation). Yeso sedimentation ended with the Joyita Member of the Los Vallos Formation, which formed by eolian and fluvial processes during lowered sea level. The Glorieta Sandstone is mostly of eolian origin, and the San Andres Formation represents shallow marine deposits. Fusulinids from the Bursum Formation at Abo Pass indicate it is early Wolfcampian in age. The Abo Formation at Abo Pass yields fossil plants, tetrapod tracks and other trace fossils, as well as vertebrate fossils of Coyote","PeriodicalId":243410,"journal":{"name":"Guidebook 67 - Geology of the Belen Area","volume":"26 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":"133467298","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}
A bstrAct — The Socorro magma body is the second largest known magma body on Earth: a partially molten sill with a thickness of ~130 m and a surface area of ~3400 km 2 that lies at ~19 km depth below central New Mexico. The largest known magma body is a similar sill of ~1 km thickness and ~5000 km 2 area in South America. Both cause active surface uplift. Understanding the emplacement and deformation histories of these large magma bodies is significant for understanding neotectonics, volcanic hazards and mid-crustal magma processes. We report the results of two-dimensional elastic crustal models (200 km wide by 30 km thick) of surface uplift due solely to conductive heat loss from a sill (60 km wide, 100 m thick, 19 km depth) and attendant thermal expansion of the surrounding host rocks, allowing us to separate surface uplift due to thermal expansion from uplift due to other causes, such as sill inflation, volume loss caused by crystallization of the sill, volume gain or loss due to melting or recrystallization of the host rocks, or isostatic adjustments. The sill is heated linearly in time from ambient temperature to 1200°C over 100 years. Net surface uplift during this heating stage is domical, somewhat wider than 140 km in diameter and ~3.5 m in amplitude, and accumulates at a nearly constant rate of ~30 mm/yr in the center. When heating ceases at 100 yr, the central uplift rate drops dramatically to <1 mm/yr and continues to decline until ~100,000 years have passed. The magnitude and rate of uplift across ~140 km of the dome remain above noise levels of repeated geodetic surveys (~1 mm/yr) for >100 yr but are well below noise levels after 1000 yr. As the uplift rate falls below
{"title":"Surface uplift due to thermal expansion around the Socorro Magma Body: preliminary results","authors":"J. V. van Wijk, G. Axen, R. Abera, S. Yao","doi":"10.56577/ffc-.217","DOIUrl":"https://doi.org/10.56577/ffc-.217","url":null,"abstract":"A bstrAct — The Socorro magma body is the second largest known magma body on Earth: a partially molten sill with a thickness of ~130 m and a surface area of ~3400 km 2 that lies at ~19 km depth below central New Mexico. The largest known magma body is a similar sill of ~1 km thickness and ~5000 km 2 area in South America. Both cause active surface uplift. Understanding the emplacement and deformation histories of these large magma bodies is significant for understanding neotectonics, volcanic hazards and mid-crustal magma processes. We report the results of two-dimensional elastic crustal models (200 km wide by 30 km thick) of surface uplift due solely to conductive heat loss from a sill (60 km wide, 100 m thick, 19 km depth) and attendant thermal expansion of the surrounding host rocks, allowing us to separate surface uplift due to thermal expansion from uplift due to other causes, such as sill inflation, volume loss caused by crystallization of the sill, volume gain or loss due to melting or recrystallization of the host rocks, or isostatic adjustments. The sill is heated linearly in time from ambient temperature to 1200°C over 100 years. Net surface uplift during this heating stage is domical, somewhat wider than 140 km in diameter and ~3.5 m in amplitude, and accumulates at a nearly constant rate of ~30 mm/yr in the center. When heating ceases at 100 yr, the central uplift rate drops dramatically to <1 mm/yr and continues to decline until ~100,000 years have passed. The magnitude and rate of uplift across ~140 km of the dome remain above noise levels of repeated geodetic surveys (~1 mm/yr) for >100 yr but are well below noise levels after 1000 yr. As the uplift rate falls below","PeriodicalId":243410,"journal":{"name":"Guidebook 67 - Geology of the Belen Area","volume":"90 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":"134417786","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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