GSA Today最新文献_第4页

Geoheritage: Progress toward Preservation 地质遗产：保护进展

GSA Today Pub Date : 2022-08-01 DOI: 10.1130/gsatgeoh-v32.1

R. Clary, W. Andrews, T. Connors

引用次数: 0

New Insights into Feeder Dike Swarms in Scoria Cones and Their Structural Control: A Case Study in the Michoacán-Guanajuato Volcanic Field 火山锥中馈线堤群及其结构控制的新认识:以Michoacán-Guanajuato火山场为例

GSA Today Pub Date : 2022-08-01 DOI: 10.1130/gsatg539a.1

M. G. Gómez-Vasconcelos, D. Avellán, J. L. Macías, Guillermo Cisneros-Máximo, J. M. Sánchez-Núñez, D. Miggins

{"title":"New Insights into Feeder Dike Swarms in Scoria Cones and Their Structural Control: A Case Study in the Michoacán-Guanajuato Volcanic Field","authors":"M. G. Gómez-Vasconcelos, D. Avellán, J. L. Macías, Guillermo Cisneros-Máximo, J. M. Sánchez-Núñez, D. Miggins","doi":"10.1130/gsatg539a.1","DOIUrl":"https://doi.org/10.1130/gsatg539a.1","url":null,"abstract":"Understanding the feeder systems in scoria cones is essential because they serve as the conduits that feed the most common eruptions worldwide. Feeder dikes and their emplacement are presumably controlled by the tectonic stress field. However, the mech-anism of dike propagation and structural control in monogenetic scoria cones remains poorly understood, as well as the conditions that allow dike swarms in scoria cones and in low magma-flux monogenetic volcanic fields.This is the first direct study of a magma feeder system in the Michoacán-Guanajuato Volcanic Field in central México. Quarrying in the Cerrito Colorado scoria cone displays six orthogonal feeder dikes—four of them are N-S oriented, parallel to the least compressive stress, intruding preexisting faults, and two are E-W oriented, perpendicular to the least compressive stress, forming their own fracture at the time of the eruption. dike networks (swarms) can develop locally in the vicinity of scoria cones and other vent structures. We suggest that bifurcation of feeder dikes can result from temporary blockages of the conduit and during changes in the magma ascent rate and magma pressure. Feeder dikes at the surface can appear as tabular dikes, cylindrical conduits, or as a combina-tion of both geometries. We suggest that tabular dikes splay-off tangentially, and cylindrical conduits bifurcate radially and axially to the main vent. Our study attests to the complexity and structural control that even small scoria cones can present.","PeriodicalId":35784,"journal":{"name":"GSA Today","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44389860","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}

引用次数: 0

SHALLOW-WATER VS. DEEP-WATER STRATIGRAPHIC GEOMETRIES IN THE ORGANIC-RICH SHALE/MUDSTONE DEBATE 富有机页岩/泥岩争论中的浅水与深水地层几何形状

GSA Today Pub Date : 2022-05-11 DOI: 10.1130/abs/2021am-364729

D. Petty

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引用次数: 1

Nuclear Winter and the Anthropocene 核冬天与人类世

GSA Today Pub Date : 2022-05-01 DOI: 10.1130/gsatg538a.1

J. Spencer

{"title":"Nuclear Winter and the Anthropocene","authors":"J. Spencer","doi":"10.1130/gsatg538a.1","DOIUrl":"https://doi.org/10.1130/gsatg538a.1","url":null,"abstract":"In 2019, the Anthropocene Working Group proposed the creation of an Anthropocene chronostratigraphic time unit to follow the Holocene Epoch. The Anthropocene time period would begin in the mid-twentieth century, coincident with rapid acceleration of multiple, ongoing anthropogenic changes to Earth’s surface and environments. Radioactive isotopes dispersed during the 1952– 1962 period of atmospheric thermonuclear-bomb tests form a proposed global marker for the beginning of the Anthropocene. This marker is proposed for purely geological rea-sons as it is reasonably precise and global in scope. These isotopes are also a marker for the initiation of a new human capacity to trigger global environmental change in a period of hours. The possibility of a global, multiyear nuclear winter following a nuclear war between North Atlantic Treaty Organization nations and Russia is suggested by recent studies of wildfires that injected sunlight-blocking smoke into the stratosphere, and by increasingly sophisticated numerical simulations of global climate following a major nuclear war. Although the proposal for an Anthropocene time period was made without consideration of the consequences of nuclear war or nuclear winter, designating the period of thermonuclear weapon tests as initiating an Anthropocene time period is supported here specifically because it indicates a new human capability for rapid and destructive environmental change on a global scale.","PeriodicalId":35784,"journal":{"name":"GSA Today","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41582200","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}

引用次数: 1

What’s Soil Got to Do with Climate Change? 土壤与气候变化有什么关系?

GSA Today Pub Date : 2022-03-01 DOI: 10.1130/gsatg519a.1

T. Longbottom, Leila Wahab, Kyungjin Min, Anna K. Jurusik, K. Moreland, M. Dolui, Touyee Thao, Melinda Gonzales, Yulissa Rojas, J. Alvarez, Zachary Malone, Jielu Yan, T. Ghezzehei, A. Berhe

{"title":"What’s Soil Got to Do with Climate Change?","authors":"T. Longbottom, Leila Wahab, Kyungjin Min, Anna K. Jurusik, K. Moreland, M. Dolui, Touyee Thao, Melinda Gonzales, Yulissa Rojas, J. Alvarez, Zachary Malone, Jielu Yan, T. Ghezzehei, A. Berhe","doi":"10.1130/gsatg519a.1","DOIUrl":"https://doi.org/10.1130/gsatg519a.1","url":null,"abstract":"Soils are the foundation of life on land and represent one of the largest global carbon (C) reservoirs. Because of the vast amount of C that they store and the continu-ous fluxes of C with the atmosphere, soil can either be part of the solution or problem with respect to climate change. Using a bank account analogy, the size and signifi-cance of the soil organic C (SOC) pool is best understood as the balance between inputs (deposits) from net primary produc-tivity and outputs (withdrawals) from SOC through decay and/or physical transport. Reversing the current problematic trend of increasing concentration of greenhouse gases in the atmosphere must be met with reduced fossil fuel emissions. At the same time, we argue that “climate-smart” land management can promote both terrestrial sequestration of atmospheric carbon dioxide (CO 2 ) and contribute to improving soil health and benefits. In this review, we highlight environments that are particularly vulnerable to SOC destabilization via land use and climatic factors and outline existing and emerging strategies that use soils to address anthropogenic climate change. Here, three contrasting eco- systems reveal differing SOC richness and dynamics: (A) agricultural, (B) grassland/shrubland, and (C) forested. Conventional agriculture (A) often leads to lower carbon stocks, and overall, less carbon input to the soil carbon pool. Grasslands (B) can harbor plants with deeper and more extensive root systems, medium to high amounts of SOC stock, and greater carbon inputs to the SOC pool. Forests (C) can have the deepest rooting system, a high amount of soil C stock, greatest density of mineral-associated C, and high rate of input of C to soils. Overall, organo-mineral association(s) and SOC pool is a function of the “balance” of C inputs and outputs in the soil organic carbon “bank account.”","PeriodicalId":35784,"journal":{"name":"GSA Today","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42527593","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}

引用次数: 1

Supplemental Material: Rapid sediment re-deposition may limit carbon release during catastrophic thermokarst lake drainage 补充材料:在灾难性热岩溶湖排水过程中，沉积物的快速再沉积可能限制碳的释放

GSA Today Pub Date : 2022-01-27 DOI: 10.1130/gsat.s.19083299

B. Burnham, E. al.

引用次数: 0

Supplemental Material: Learning from the COVID-19 Pandemic: How Faculty Experiences Can Prepare Us for Future System-Wide Disruption 补充材料:从COVID-19大流行中学习:教师经验如何使我们为未来的全系统中断做好准备

GSA Today Pub Date : 2021-12-15 DOI: 10.1130/gsat.s.17209481

K. Bateman, et al.

引用次数: 1

Supplemental Material: Continental Magmatism and Uplift as the Primary Driver for First-Order Oceanic 87Sr/86Sr Variability with Implications for Global Climate and Atmospheric Oxygenation 补充材料:大陆岩浆活动和隆升是海洋87Sr/86Sr一级变率的主要驱动因素及其对全球气候和大气氧化的影响

GSA Today Pub Date : 2021-11-05 DOI: 10.1130/gsat.s.16942894

T. Paulsen, E. al.

引用次数: 3

Mapping Critical Minerals from the Sky 绘制来自天空的关键矿物

GSA Today Pub Date : 2021-09-01 DOI: 10.1130/gsatg512a.1

A. Shah, Robby Morrow, Michael M. Pace, M. Harris, W. Doar

{"title":"Mapping Critical Minerals from the Sky","authors":"A. Shah, Robby Morrow, Michael M. Pace, M. Harris, W. Doar","doi":"10.1130/gsatg512a.1","DOIUrl":"https://doi.org/10.1130/gsatg512a.1","url":null,"abstract":"Critical mineral resources titanium, zirconium, and rare earth elements occur in placer deposits over vast parts of the U.S. Atlantic Coastal Plain. Key questions regarding provenance, pathways of minerals to deposit sites, and relations to geologic features remain unexplained. As part of a national effort to collect data over regions prospective for critical minerals, the first public high-resolution aeroradiometric survey over the U.S. Atlantic Coastal Plain was conducted over Quaternary sediments in South Carolina. The new data provide an unprecedented view of potential deposits by imaging Th-bearing minerals in the heavy mineral assemblage. Sand ridges show the highest radiometric Th values with localized, linear anomalies, especially along the shoreface and in areas reworked by multiple processes and/or during multiple episodes. Estuarine areas with finer-grained sediments show lower, distributed Th anomalies. Th values averaged over geologic unit areas are similar for both environments, suggesting that heavy minerals are present but have not been locally concentrated in the lower-energy estuarine environments. Radiometric K highlights immature minerals such as mica and potassium feldspar. K is elevated within shallow sediments younger than ca. 130 ka, an attribute that persists in regional data from northern South Carolina to northern Florida. Both K and Th are elevated over the floodplains of the Santee River and other rivers with headwaters in the igneous and metamorphic Piedmont Terrane. The persistence of K anomalies for distances of more than 100 km from the Santee River floodplain suggests that heavy minerals are delivered from the Piedmont to offshore areas by major rivers, transported along the coast by the longshore current, and redeposited onshore by marine processes.","PeriodicalId":35784,"journal":{"name":"GSA Today","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47562103","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}

引用次数: 2

Supplemental Material: ‘Taters versus Sliders: Evidence for a Long-Lived History of Strike-Slip Displacement along the Canadian Arctic Transform System (CATS) 补充材料：“Taters与Sliders：加拿大北极转换系统（CATS）走滑位移长期历史的证据”

GSA Today Pub Date : 2021-07-01 DOI: 10.1130/GSATG500A.1

W. McClelland, J. Strauss, M. Colpron, J. Gilotti, K. Faehnrich, S. Malone, G. Gehrels, F. Macdonald, J. Oldow

引用次数: 8