Currently Fabaceae, is one of the dominant families of the Seasonally Dry Tropical Forests or Neotropical seasonal dry forests. Anadenanthera which integrates the family, has wide geographical distribution in South America and the West Indies, but in Argentina it`s only present Anadenantera colubrina var. cebil in the north and their records are represented from the Miocene to the present through palynomorphs and mineralized woods. The main objective of this work is to contribute to the understanding in the context of the history of Anadenanthera during the Neogene and Quaternary in Argentina, on the basis of the review and integration of the paleobotanical history, geological and climatic available that have affected the genre in the country. Studied fossil materials come from different geological formations of Argentina: Chenque Formation (Miocene), Parana Formation (Middle Miocene), San Jose Formation (Middle Miocene), Ituzaingo Formation (Pliocene) and Ibera (Holocene). The material found on the Chenque Formation is referred to Polyadopollenites coincides with the described material for the Middle Miocene of the central-eastern Argentina and the Pliocene of northeast Argentina. On the other hand in Parana and Ituzaingo Formation studied sample of mineralized woods of Anadenantheroxylon villaurquisense , finally the sample found in Holocene of Ibera Corrientes Province corresponds to Anadenanthera colubrina var. macrocarpa . With these data it can be concluded that Anadenathera had a wide geographical record in Miocene and Holocene of Argentina, it was found in sediments from the lower Miocene of Patagonia by integrating a Subtropical Paleoflora. From the Middle-Upper Miocene integrated the vegetation in northeast Argentine constituting xerophiles forests. Their last record is equivalent to the Middle Holocene of sediments from Ibera integrating the regional vegetation and indicating an open vegetation characteristics of dry environments. Finally it`s noteworthy that the spatial and temporal succession of Anadenanthera in Argentina, would have been intimately associated with tectonic and climatic events occurred during the Neogene and Quaternary.
豆科植物是热带季节性干燥林或新热带季节性干燥林的优势科之一。整合科的Anadenanthera在南美洲和西印度群岛有广泛的地理分布，但在阿根廷只存在于北部的Anadenantera colubrina var. cebil，它们的记录从中新世到现在，通过形态和矿化森林表现出来。本研究的主要目的是通过对阿根廷影响该类型的古植物学历史、地质和气候资料的回顾和整合，对阿根廷新近纪和第四纪Anadenanthera的历史背景进行了解。研究的化石材料来自阿根廷不同的地质构造:中新世Chenque组、中中新世Parana组、中中新世San Jose组、上新世Ituzaingo组和全新世Ibera。在Chenque组发现的材料被称为多adopolenites，与阿根廷中东部中新世和阿根廷东北部上新世的材料一致。另一方面，在Parana组和Ituzaingo组研究了Anadenantheroxylon villaurquisense的矿化木材样品，最终在Ibera Corrientes省全新世发现的样品与Anadenanthera colubrina var. macrocarpa相对应。由此可以得出结论，Anadenathera在阿根廷中新世和全新世有广泛的地理记录，它是通过整合亚热带古植物群在巴塔哥尼亚中新世下的沉积物中发现的。中新世中上段开始，阿根廷东北部的植被整合形成了嗜干森林。他们的最后记录相当于中全新世伊比利亚的沉积物，整合了区域植被，表明干旱环境下的开放植被特征。最后，值得注意的是，阿根廷Anadenanthera的时空演替可能与新近纪和第四纪的构造和气候事件密切相关。
{"title":"Registro fósil y distribución de Anadenathera en Argentina desde el Mioceno hasta la actualidad","authors":"L. Fernandez-Pacella","doi":"10.3989/EGEOL.41834.343","DOIUrl":"https://doi.org/10.3989/EGEOL.41834.343","url":null,"abstract":"Currently Fabaceae, is one of the dominant families of the Seasonally Dry Tropical Forests or Neotropical seasonal dry forests. Anadenanthera which integrates the family, has wide geographical distribution in South America and the West Indies, but in Argentina it`s only present Anadenantera colubrina var. cebil in the north and their records are represented from the Miocene to the present through palynomorphs and mineralized woods. The main objective of this work is to contribute to the understanding in the context of the history of Anadenanthera during the Neogene and Quaternary in Argentina, on the basis of the review and integration of the paleobotanical history, geological and climatic available that have affected the genre in the country. Studied fossil materials come from different geological formations of Argentina: Chenque Formation (Miocene), Parana Formation (Middle Miocene), San Jose Formation (Middle Miocene), Ituzaingo Formation (Pliocene) and Ibera (Holocene). The material found on the Chenque Formation is referred to Polyadopollenites coincides with the described material for the Middle Miocene of the central-eastern Argentina and the Pliocene of northeast Argentina. On the other hand in Parana and Ituzaingo Formation studied sample of mineralized woods of Anadenantheroxylon villaurquisense , finally the sample found in Holocene of Ibera Corrientes Province corresponds to Anadenanthera colubrina var. macrocarpa . With these data it can be concluded that Anadenathera had a wide geographical record in Miocene and Holocene of Argentina, it was found in sediments from the lower Miocene of Patagonia by integrating a Subtropical Paleoflora. From the Middle-Upper Miocene integrated the vegetation in northeast Argentine constituting xerophiles forests. Their last record is equivalent to the Middle Holocene of sediments from Ibera integrating the regional vegetation and indicating an open vegetation characteristics of dry environments. Finally it`s noteworthy that the spatial and temporal succession of Anadenanthera in Argentina, would have been intimately associated with tectonic and climatic events occurred during the Neogene and Quaternary.","PeriodicalId":50496,"journal":{"name":"Estudios Geologicos-Madrid","volume":"7 1","pages":"031"},"PeriodicalIF":0.7,"publicationDate":"2015-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82225737","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The largest extinction of deep-sea benthic foraminifera in the Cenozoic occurred during the Paleocene-Eocene Thermal Maximum event (PETM, ~55.8 Ma). Much has been speculated about the causes of such extinction, and proposed mechanisms include changes in productivity and/or oxygenation of bottom waters, metabolic changes and in the composition of the food supply to the seafloor, or the ocean acidification related to the massive input of isotopically light carbon into the ocean-atmosphere system, among others. Here we analyse ocean acidification as a potential triggering mechanism of the extinctions. The early Eocene at the Zumaya section (Basque-Cantabrian Basin) is marked by a 4 m-thick interval with a very low CaCO 3 content. In order to analyse whether CaCO 3 dissolution had a direct effect on the extinctions across the PETM, we car-ried out dissolution experiments on various species of agglutinated benthic foraminifera from Zumaya. In general, agglutinated species that do not disappear in the interval of most intense dissolution at Zumaya were not -or only slightly- affected by our dissolution experiments, since they do not have calcareous particles or cement. However, some species that went extinct or locally disappeared during the early Eocene, such as Dorothia cylindracea, Spiroplectammina spectabilis and Haplophragmoides cf. walteri , are resistant to dissolution. These results sug-gest that, in addition to ocean acidification, other factors must have contributed to the destabilization of benthic foraminiferal assemblages.
{"title":"Experimentos de disolución de CaCO 3 en foraminíferos bentónicos aglutinados del Paleoceno-Eoceno en Zumaya (Cuenca Vasco-Cantábrica, España)","authors":"G. Arreguín-Rodríguez, L. Alegret","doi":"10.3989/EGEOL.41758.330","DOIUrl":"https://doi.org/10.3989/EGEOL.41758.330","url":null,"abstract":"The largest extinction of deep-sea benthic foraminifera in the Cenozoic occurred during the Paleocene-Eocene Thermal Maximum event (PETM, ~55.8 Ma). Much has been speculated about the causes of such extinction, and proposed mechanisms include changes in productivity and/or oxygenation of bottom waters, metabolic changes and in the composition of the food supply to the seafloor, or the ocean acidification related to the massive input of isotopically light carbon into the ocean-atmosphere system, among others. \u0000Here we analyse ocean acidification as a potential triggering mechanism of the extinctions. The early Eocene at the Zumaya section (Basque-Cantabrian Basin) is marked by a 4 m-thick interval with a very low CaCO 3 content. In order to analyse whether CaCO 3 dissolution had a direct effect on the extinctions across the PETM, we car-ried out dissolution experiments on various species of agglutinated benthic foraminifera from Zumaya. In general, agglutinated species that do not disappear in the interval of most intense dissolution at Zumaya were not -or only slightly- affected by our dissolution experiments, since they do not have calcareous particles or cement. However, some species that went extinct or locally disappeared during the early Eocene, such as Dorothia cylindracea, Spiroplectammina spectabilis and Haplophragmoides cf. walteri , are resistant to dissolution. These results sug-gest that, in addition to ocean acidification, other factors must have contributed to the destabilization of benthic foraminiferal assemblages.","PeriodicalId":50496,"journal":{"name":"Estudios Geologicos-Madrid","volume":"18 1","pages":"023"},"PeriodicalIF":0.7,"publicationDate":"2015-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77658318","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
C. Laplana, E. Herráez, J. Y. S. D. L. Terreros, S. Bárez, Susana Rubio-Jara, Joaquín Panera, I. Rus, A. Pérez-González
Due to the construction of the Stormwater Tank in Villaverde (Madrid), two new Pleistocene vertebrate bearing sites were discovered within the sediments of the Complex Terrace of Butarque (TCB, in Spanish), called H-02 and H-03. Termoluminiscence (TL) dates placed the first site at the Late Pleistocene, more precisely at the end of the MIS 5. An older age within the Middle Pleistocene was obtained for H-03 (Dominguez-Alonso et al. , 2009). In this work, we evaluate the agreement between the TL dates and the estimated ages resulting from the biochronological interpretation of the fossil mammal assemblages recovered in both sites. Whereas for H-03 there is consistency between the TL dating and the age estimated based on biocronological criteria, this is not the case for H-02. At this site, the presence of Microtus brecciensis points to an older age than the proposal based on TL, within the Middle Pleistocene. On the other hand, comparison of some biometric features between the H-02 and Aridos 1 populations of the last species allows to establish a younger age for the first site with regard to the second one. Taking into account the available dates for Aridos 1, which placed this site at the end of the MIS 11 (Panera et al. , 2011), the age of H-02 must therefore be included in the last quarter of the Middle Pleistocene. In summary, TL dates for the H-02 site and, perhaps, some others obtained for the Stormwater Tank in Villaverde, seem to be minimum estimations of the age of the sediments, and do not represent their real age.
由于Villaverde (Madrid)的雨水池的建设，在Butarque复杂阶地(TCB，西班牙语)的沉积物中发现了两个新的更新世脊椎动物所在地，称为H-02和H-03。Termoluminiscence (TL)日期将第一个地点定位在晚更新世，更准确地说是在MIS 5的末期。H-03的年龄在中更新世(Dominguez-Alonso et al.， 2009)。在这项工作中，我们评估了在两个地点发现的化石哺乳动物组合的生物年代学解释得出的TL日期和估计年龄之间的一致性。对于H-03来说，TL测年和基于生物年代学标准估计的年龄是一致的，而对于H-02来说，情况并非如此。在这个地点，角砾岩Microtus brecciensis的存在表明它的年龄比基于TL的建议更早，在中更新世。另一方面，对最后一个物种的H-02和Aridos 1种群的一些生物特征进行比较，可以确定第一个地点相对于第二个地点的年龄更小。考虑到Aridos 1的可用日期，它将该遗址置于MIS 11的末尾(Panera et al.， 2011)，因此H-02的年龄必须包括在中更新世的最后一个季度。总而言之，H-02站点的TL日期，也许还有Villaverde的雨水池的其他一些日期，似乎是沉积物年龄的最低估计，并不能代表它们的真实年龄。
{"title":"Biocronología de la Terraza Compleja de Butarque del río Manzanares en el Estanque de Tormentas al sur de Madrid (España)","authors":"C. Laplana, E. Herráez, J. Y. S. D. L. Terreros, S. Bárez, Susana Rubio-Jara, Joaquín Panera, I. Rus, A. Pérez-González","doi":"10.3989/EGEOL.41808.338","DOIUrl":"https://doi.org/10.3989/EGEOL.41808.338","url":null,"abstract":"Due to the construction of the Stormwater Tank in Villaverde (Madrid), two new Pleistocene vertebrate bearing sites were discovered within the sediments of the Complex Terrace of Butarque (TCB, in Spanish), called H-02 and H-03. Termoluminiscence (TL) dates placed the first site at the Late Pleistocene, more precisely at the end of the MIS 5. An older age within the Middle Pleistocene was obtained for H-03 (Dominguez-Alonso et al. , 2009). In this work, we evaluate the agreement between the TL dates and the estimated ages resulting from the biochronological interpretation of the fossil mammal assemblages recovered in both sites. Whereas for H-03 there is consistency between the TL dating and the age estimated based on biocronological criteria, this is not the case for H-02. At this site, the presence of Microtus brecciensis points to an older age than the proposal based on TL, within the Middle Pleistocene. On the other hand, comparison of some biometric features between the H-02 and Aridos 1 populations of the last species allows to establish a younger age for the first site with regard to the second one. Taking into account the available dates for Aridos 1, which placed this site at the end of the MIS 11 (Panera et al. , 2011), the age of H-02 must therefore be included in the last quarter of the Middle Pleistocene. In summary, TL dates for the H-02 site and, perhaps, some others obtained for the Stormwater Tank in Villaverde, seem to be minimum estimations of the age of the sediments, and do not represent their real age.","PeriodicalId":50496,"journal":{"name":"Estudios Geologicos-Madrid","volume":"54 1","pages":"028"},"PeriodicalIF":0.7,"publicationDate":"2015-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75329312","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fernando Gázquez, F. Rull, José María Calaforra, G. Venegas, José Antonio Carbonero Manrique, A. Sanz, Jesús Medina, A. Catalá-Espí, A. Sansano, R. Navarro, Paolo Forti, J. D. Waele, J. Martínez-Frías
The recent discovery of hydrated sulfates on the Martian surface suggests that widespread wet conditions were present during its early geological history. Upon this discovery, a growing interest has emerged in the study of this group of minerals from terrestrial environments as potential Martian analogs. Here, we evaluate the potential of various analytical techniques involved in current and future mission to Mars for detecting hydrated minerals from caves and mines of Spain and the mining district of Iglesias-Carbonia (Sardinia, Italy). Minerals were analyzed by Raman spectroscopy, which will be included in the payload of the ESA’s 2018 ExoMars mission. On the other hand, IR spectroscopy, also included in the ExoMars mission, as well as LIBS spectroscopy and a combined XRD-XRF analyzer, both onboard the Curiosity rover of NASA’s MSL mission, were utilized. Hydrated sulfates (gypsum, epsomite, jarosite and glaucocerinite), silicates (hemimorphite) and carbonates (hydrozincite and hydromagnesite) were characterized. Most of these minerals have also been detected on the Martian surface. The mechanisms involved in the genesis of these minerals and the potential analogies with the minerogenesis on Mars are discussed. The Raman-LIBS combination appears to be the most powerful tool for detecting hydrated minerals in Martian conditions. This technology will probably be considered to be onboard of further planetary missions.
{"title":"Caracterización mineralógica y geoquímica de minerales hidratados de ambientes subterráneos: implicaciones para la exploración planetaria","authors":"Fernando Gázquez, F. Rull, José María Calaforra, G. Venegas, José Antonio Carbonero Manrique, A. Sanz, Jesús Medina, A. Catalá-Espí, A. Sansano, R. Navarro, Paolo Forti, J. D. Waele, J. Martínez-Frías","doi":"10.3989/EGEOL.41688.314","DOIUrl":"https://doi.org/10.3989/EGEOL.41688.314","url":null,"abstract":"The recent discovery of hydrated sulfates on the Martian surface suggests that widespread wet conditions were present during its early geological history. Upon this discovery, a growing interest has emerged in the study of this group of minerals from terrestrial environments as potential Martian analogs. Here, we evaluate the potential of various analytical techniques involved in current and future mission to Mars for detecting hydrated minerals from caves and mines of Spain and the mining district of Iglesias-Carbonia (Sardinia, Italy). Minerals were analyzed by Raman spectroscopy, which will be included in the payload of the ESA’s 2018 ExoMars mission. On the other hand, IR spectroscopy, also included in the ExoMars mission, as well as LIBS spectroscopy and a combined XRD-XRF analyzer, both onboard the Curiosity rover of NASA’s MSL mission, were utilized. Hydrated sulfates (gypsum, epsomite, jarosite and glaucocerinite), silicates (hemimorphite) and carbonates (hydrozincite and hydromagnesite) were characterized. Most of these minerals have also been detected on the Martian surface. The mechanisms involved in the genesis of these minerals and the potential analogies with the minerogenesis on Mars are discussed. The Raman-LIBS combination appears to be the most powerful tool for detecting hydrated minerals in Martian conditions. This technology will probably be considered to be onboard of further planetary missions.","PeriodicalId":50496,"journal":{"name":"Estudios Geologicos-Madrid","volume":"16 1","pages":"009"},"PeriodicalIF":0.7,"publicationDate":"2014-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81606833","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. G. Rejas, J. Martínez-Frías, R. Martínez, Miguel Marchamalo, J. Bonatti
The aim of this work is the comparative study of methods for calculating spectral anomalies from imaging spectrometry in several test areas of the Central Volcanic Range (CVR) of Costa Rica. In the detection of anomalous responses it is assumed no prior knowledge of the targets, so that the pixels are automatically separated according to their spectral information significantly differentiated with respect to a background to be estimated, either globally for the full scene, either locally by image segmentation techniques. We used spectral ranges of visible-near infrared (VNIR), shortwave infrared (SWIR) and thermal (TIR) data cubes hiperepectrales from HyMAP airborne sensors and MASTER. We have designed experiments on natural scenes of the CVC, and semi-urban of different complexity, analyzing the behavior of the standard RX (Reed & Xiaoli, 1990) anomaly detector and different approaches based on imaging and dimensionality reduction. In this paper we propose a new technique for anomaly detection in hyperspectral data called DAFT (Detector de Anomalias de Fondo Termico), as a Projection Pursuit (Malpica et al. , 2008) variant, based on dimensionality reduction by projecting anomalies or targets with unknown spectral signature to the background, in a range thermal spectrum wavelengths. We discuss the results considering their implications on geological processes, as well as their use as terrestrial analogs for planetary exploration.
这项工作的目的是比较研究哥斯达黎加中央火山山脉(CVR)几个试验区的成像光谱计算方法。在异常响应的检测中，假设对目标没有先验知识，因此根据其光谱信息自动分离像素，这些像素相对于待估计的背景有显著的差异，无论是全局的整个场景，还是局部的图像分割技术。我们使用了来自HyMAP机载传感器和MASTER的可见光-近红外(VNIR)，短波红外(SWIR)和热(TIR)数据立方体的光谱范围。我们设计了不同复杂程度的CVC和半城市自然场景实验，分析了标准RX (Reed & Xiaoli, 1990)异常检测器的行为以及基于成像和降维的不同方法。在本文中，我们提出了一种用于高光谱数据异常检测的新技术，称为DAFT (Detector de Anomalias de Fondo Termico)，作为投影追踪(Malpica et al.， 2008)的变体，基于在热光谱波长范围内将具有未知光谱特征的异常或目标投影到背景中的降维方法。我们讨论的结果考虑到它们对地质过程的影响，以及它们作为地球类似物用于行星探测。
{"title":"Análisis espectral de materiales geológicos en la Cordillera Volcánica Central de Costa Rica y su relación con la detección remota de anomalías","authors":"J. G. Rejas, J. Martínez-Frías, R. Martínez, Miguel Marchamalo, J. Bonatti","doi":"10.3989/EGEOL.41711.313","DOIUrl":"https://doi.org/10.3989/EGEOL.41711.313","url":null,"abstract":"The aim of this work is the comparative study of methods for calculating spectral anomalies from imaging spectrometry in several test areas of the Central Volcanic Range (CVR) of Costa Rica. In the detection of anomalous responses it is assumed no prior knowledge of the targets, so that the pixels are automatically separated according to their spectral information significantly differentiated with respect to a background to be estimated, either globally for the full scene, either locally by image segmentation techniques. \u0000We used spectral ranges of visible-near infrared (VNIR), shortwave infrared (SWIR) and thermal (TIR) data cubes hiperepectrales from HyMAP airborne sensors and MASTER. We have designed experiments on natural scenes of the CVC, and semi-urban of different complexity, analyzing the behavior of the standard RX (Reed & Xiaoli, 1990) anomaly detector and different approaches based on imaging and dimensionality reduction. In this paper we propose a new technique for anomaly detection in hyperspectral data called DAFT (Detector de Anomalias de Fondo Termico), as a Projection Pursuit (Malpica et al. , 2008) variant, based on dimensionality reduction by projecting anomalies or targets with unknown spectral signature to the background, in a range thermal spectrum wavelengths. We discuss the results considering their implications on geological processes, as well as their use as terrestrial analogs for planetary exploration.","PeriodicalId":50496,"journal":{"name":"Estudios Geologicos-Madrid","volume":"31 1","pages":"011"},"PeriodicalIF":0.7,"publicationDate":"2014-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81797978","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
To achieve the apparently simple Periodic Table of the Elements has implied tremendous efforts over thousands of years. In this paper we present a brief history of the discovery of the chemical elements from prehistory to the present day, revealing the controversies that arose on the way and claiming the important work performed by alchemists in the advancement of knowledge. This is especially important if we consider that alchemy had a period of existence of many thousands of years, while the “Chemistry”, officially established as a science in the eighteenth century, has operated as such for only a few hundred years. Even so, if we consider the progress of discovery and isolation of chemical elements throughout history, it can be observed that the number of elements identified is achieved mainly in the nineteenth and twentieth centuries, reflecting the development of instrumental techniques, that facilitated this task.
{"title":"De los dioses a los hombres: Un recorrido histórico del descubrimiento de los elementos químicos","authors":"I. González","doi":"10.3989/EGEOL.41718.316","DOIUrl":"https://doi.org/10.3989/EGEOL.41718.316","url":null,"abstract":"To achieve the apparently simple Periodic Table of the Elements has implied tremendous efforts over thousands of years. In this paper we present a brief history of the discovery of the chemical elements from prehistory to the present day, revealing the controversies that arose on the way and claiming the important work performed by alchemists in the advancement of knowledge. This is especially important if we consider that alchemy had a period of existence of many thousands of years, while the “Chemistry”, officially established as a science in the eighteenth century, has operated as such for only a few hundred years. Even so, if we consider the progress of discovery and isolation of chemical elements throughout history, it can be observed that the number of elements identified is achieved mainly in the nineteenth and twentieth centuries, reflecting the development of instrumental techniques, that facilitated this task.","PeriodicalId":50496,"journal":{"name":"Estudios Geologicos-Madrid","volume":"256 1","pages":"015"},"PeriodicalIF":0.7,"publicationDate":"2014-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88173448","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Pedregal granite outcrops in the Central Iberian Zone, northern Portugal, in the eastern border of a synorogenic variscan granite-migmatite complex sub-concordant with the regional metamorphic structures. It is a granitoid (ca. 3 km 2 ) with an elongated NW-SE shape intruded in staurolite-micaschist and banded gneiss-migmatite rocks, with local igneous breccias in the contact. The country rocks belong to a metapelitic and metasammitic sequence of Edicarian-Cambrian age, known as the “Complexo Xisto-Grauvaquico” (CXG) which shows a main regional foliation with a NW-SE to NNW-SSE direction. The Pedregal granite is peraluminous (its A/CNK parameter ranges from 1.18 to 1.62), with a magnesian and alkali to alkali-calcic signature. The peculiar features of the granite are high contents of Zr (389 to 435 ppm) and a LREE flat pattern, which are uncommon characteristics for granitic rocks, as well as the corroded shape of the biotite, and the large amount of secondary muscovite. These peculiar features distinguish it from the adjacent synorogenic granites. The field, petrographical and chemical features of the Pedregal granite are in accordance with a second phase of partial melting of a residuum, depleted by melt segregation during a first melting episode with the involvement of peritectic garnet and abundant residual biotite with LREE- and Zr-bearing accessory minerals. Besides, the intrusive character of the granite, and the presence of metasedimentary xenoliths point out to a secondary diatexite.
{"title":"El granito de Pedregal (Portugal): caracterización petrográfica y geoquímica de un granitoide peculiar","authors":"J. A. Ferreira, M. A. Ribeiro, H. Martins","doi":"10.3989/EGEOL.41730.321","DOIUrl":"https://doi.org/10.3989/EGEOL.41730.321","url":null,"abstract":"The Pedregal granite outcrops in the Central Iberian Zone, northern Portugal, in the eastern border of a synorogenic variscan granite-migmatite complex sub-concordant with the regional metamorphic structures. It is a granitoid (ca. 3 km 2 ) with an elongated NW-SE shape intruded in staurolite-micaschist and banded gneiss-migmatite rocks, with local igneous breccias in the contact. The country rocks belong to a metapelitic and metasammitic sequence of Edicarian-Cambrian age, known as the “Complexo Xisto-Grauvaquico” (CXG) which shows a main regional foliation with a NW-SE to NNW-SSE direction. The Pedregal granite is peraluminous (its A/CNK parameter ranges from 1.18 to 1.62), with a magnesian and alkali to alkali-calcic signature. The peculiar features of the granite are high contents of Zr (389 to 435 ppm) and a LREE flat pattern, which are uncommon characteristics for granitic rocks, as well as the corroded shape of the biotite, and the large amount of secondary muscovite. These peculiar features distinguish it from the adjacent synorogenic granites. \u0000The field, petrographical and chemical features of the Pedregal granite are in accordance with a second phase of partial melting of a residuum, depleted by melt segregation during a first melting episode with the involvement of peritectic garnet and abundant residual biotite with LREE- and Zr-bearing accessory minerals. Besides, the intrusive character of the granite, and the presence of metasedimentary xenoliths point out to a secondary diatexite.","PeriodicalId":50496,"journal":{"name":"Estudios Geologicos-Madrid","volume":"104 1","pages":"019"},"PeriodicalIF":0.7,"publicationDate":"2014-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87651001","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A group of slightly peraluminous Variscan plutons in Northern Portugal were selected from the study of zircon composition. The selected plutons are: the Vila Pouca de Aguiar and the Lavadores-Madalena plutons with I-type affinities and the Vieira do Minho pluton, an l-S transitional type. Zircon occurs as euhedral to subhedral crystals and exhibit finely concentric oscillatory magmatic zoning mainly related to variations of Hf, Y, U and Th concentrations. Most zircon crystals show the dominant “xenotime” substitution. The zircon crystals have Zr/Hf ratio in the range of 21 to 52, with no significant differences between the different granites. These values are in the same range of other peraluminous granites and are in accordance with a crustal signature of zircon. Moreover, the range of Zr/Hf values in zircon crystals overlaps with that of crustal sources and consequently to the potential protoliths proposed in the genesis of the Vieira do Minho and the Vila Pouca de Aguiar plutons, namely meta-igneous crustal sources at different levels. Although zircon from the Lavadores-Madalena pluton has a compositional range similar to the other plutons, an origin by hibridisation has been proposed. However, similar zircon chemistry between this pluton and Vila Pouca de Aguiar and Vieira do Minho plutons could also suggest a similar crustal source.
对葡萄牙北部的一组略过铝的Variscan岩体进行了锆石组成研究。选择的岩体有:具有i型亲和关系的Vila Pouca de Aguiar和Lavadores-Madalena岩体和l-S过渡型的Vieira do Minho岩体。锆石以自面体-亚面体晶体形式赋存，呈现出精细的同心振荡岩浆分带，主要与Hf、Y、U和Th的富集变化有关。大多数锆石晶体表现为“xenotime”取代。锆石晶体的Zr/Hf比值在21 ~ 52之间，不同花岗岩之间差异不显著。这些值与其他过铝花岗岩相同，与锆石的地壳特征一致。此外，锆石晶体的Zr/Hf值范围与地壳源范围重叠，从而与Vieira do Minho和Vila Pouca de Aguiar岩体成因中提出的潜在原岩重叠，即不同层次的变质火成岩地壳源。尽管来自Lavadores-Madalena岩体的锆石具有与其他岩体相似的成分范围，但有人提出了一种杂化成因。然而，该岩体与Vila Pouca de Aguiar和Vieira do Minho岩体之间相似的锆石化学成分也可能表明类似的地壳来源。
{"title":"Composición del circón de granitos variscos del Norte de Portugal","authors":"H. Martins, J. Abreu","doi":"10.3989/EGEOL.41729.318","DOIUrl":"https://doi.org/10.3989/EGEOL.41729.318","url":null,"abstract":"A group of slightly peraluminous Variscan plutons in Northern Portugal were selected from the study of zircon composition. The selected plutons are: the Vila Pouca de Aguiar and the Lavadores-Madalena plutons with I-type affinities and the Vieira do Minho pluton, an l-S transitional type. Zircon occurs as euhedral to subhedral crystals and exhibit finely concentric oscillatory magmatic zoning mainly related to variations of Hf, Y, U and Th concentrations. Most zircon crystals show the dominant “xenotime” substitution. The zircon crystals have Zr/Hf ratio in the range of 21 to 52, with no significant differences between the different granites. These values are in the same range of other peraluminous granites and are in accordance with a crustal signature of zircon. Moreover, the range of Zr/Hf values in zircon crystals overlaps with that of crustal sources and consequently to the potential protoliths proposed in the genesis of the Vieira do Minho and the Vila Pouca de Aguiar plutons, namely meta-igneous crustal sources at different levels. Although zircon from the Lavadores-Madalena pluton has a compositional range similar to the other plutons, an origin by hibridisation has been proposed. However, similar zircon chemistry between this pluton and Vila Pouca de Aguiar and Vieira do Minho plutons could also suggest a similar crustal source.","PeriodicalId":50496,"journal":{"name":"Estudios Geologicos-Madrid","volume":"26 1","pages":"018"},"PeriodicalIF":0.7,"publicationDate":"2014-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90081809","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
D. Daza, M. Bustillo, C. Recio, M. R. Carvalho, J. Nunes
The volcanic caves of Algar do Carvao (a pit with a complex genesis) and of Branca Opala (a lava-tube cave), differ from other caves on the island of Terceira by having speleothems composed only by opal. This kind of speleothems, in volcanic caves, suggests that the silica origin can be related to hydrothermal activity. The objective of this study is to determine the speleothem isotopic composition in δ¹⁸O SMOW and δD SMOW to determine their geochemical signature and conditions of formation. The studied samples from Algar do Carvao pit are stalactites and flowstones/gours that have been formed in subaerial conditions, while those from the Branca Opala lava tube have been defined as underwater silica stromatolites. dD data of speleothems from both caves are relatively similar (−102.0 ± 10.5‰ in Branca Opala and −103.7 ± 11.1‰ in Algar do Carvao) and it can be assumed that the fluids involved in the silica deposition may be similar. Moreover the δ¹⁸O SMOW data show that the Algar do Carvao speleothems have higher values (δ¹⁸O SMOW 39,4 ± 0,3‰), relatively to the Branca Opala stromatolites (δ¹⁸O SMOW 35,2 ± 0,8‰). The diagenesis that affected the opal A may explain, in part, the observed differences. However, other genetic factors are also influencing such as the fact that Algar do Carvao stalactites are formed in sub aerial conditions, under the influence of evaporation processes, while Branca Opala speleothems were formed in underwater conditions. However, it is also possible, that the water that originated the Branca Opala speleothems was 10,7 °C warmer than the water that formed the Algar do Carvao stalactites.
Algar do Carvao(一个成因复杂的坑)和Branca Opala(一个熔岩管洞穴)的火山洞穴与特塞拉岛上的其他洞穴不同，它们的洞穴主题仅由蛋白石组成。在火山洞穴中发现的这类洞穴化石表明，二氧化硅的成因可能与热液活动有关。本研究的目的是测定δ¹⁸O SMOW和δ d SMOW中岩浆岩的同位素组成，以确定其地球化学特征和形成条件。来自Algar do Carvao坑的研究样本是在陆地条件下形成的钟乳石和流石/砾石，而来自Branca Opala熔岩管的研究样本被定义为水下二氧化硅叠层石。两个岩洞的溶洞元素dD值较为相似(Branca Opala为- 102.0±10.5‰，Algar do Carvao为- 103.7±11.1‰)，可以推测溶洞中石英沉积的流体可能相似。此外，δ¹⁸O SMOW数据表明，Algar do Carvao岩石层的δ¹⁸O SMOW值为39.4±0.3‰，高于Branca Opala叠层石(δ¹⁸O SMOW 35,2±0.8‰)。影响蛋白石A的成岩作用可以部分解释观察到的差异。然而，其他遗传因素也有影响，例如Algar do Carvao钟乳石是在水下条件下在蒸发过程的影响下形成的，而Branca Opala洞穴是在水下条件下形成的。然而，也有可能，形成Branca Opala洞穴的水比形成Algar do Carvao钟乳石的水要温暖10.7°C。
{"title":"Composición isotópica (δ¹⁸ O y δD) de espeleotemas silíceos en las cuevas volcánicas de Algar do Carvão y Branca Opala (Isla Terceira, Azores, Portugal)","authors":"D. Daza, M. Bustillo, C. Recio, M. R. Carvalho, J. Nunes","doi":"10.3989/EGEOL.41717.315","DOIUrl":"https://doi.org/10.3989/EGEOL.41717.315","url":null,"abstract":"The volcanic caves of Algar do Carvao (a pit with a complex genesis) and of Branca Opala (a lava-tube cave), differ from other caves on the island of Terceira by having speleothems composed only by opal. This kind of speleothems, in volcanic caves, suggests that the silica origin can be related to hydrothermal activity. The objective of this study is to determine the speleothem isotopic composition in δ¹⁸O SMOW and δD SMOW to determine their geochemical signature and conditions of formation. \u0000The studied samples from Algar do Carvao pit are stalactites and flowstones/gours that have been formed in subaerial conditions, while those from the Branca Opala lava tube have been defined as underwater silica stromatolites. \u0000dD data of speleothems from both caves are relatively similar (−102.0 ± 10.5‰ in Branca Opala and −103.7 ± 11.1‰ in Algar do Carvao) and it can be assumed that the fluids involved in the silica deposition may be similar. Moreover the δ¹⁸O SMOW data show that the Algar do Carvao speleothems have higher values (δ¹⁸O SMOW 39,4 ± 0,3‰), relatively to the Branca Opala stromatolites (δ¹⁸O SMOW 35,2 ± 0,8‰). The diagenesis that affected the opal A may explain, in part, the observed differences. However, other genetic factors are also influencing such as the fact that Algar do Carvao stalactites are formed in sub aerial conditions, under the influence of evaporation processes, while Branca Opala speleothems were formed in underwater conditions. However, it is also possible, that the water that originated the Branca Opala speleothems was 10,7 °C warmer than the water that formed the Algar do Carvao stalactites.","PeriodicalId":50496,"journal":{"name":"Estudios Geologicos-Madrid","volume":"33 1","pages":"010"},"PeriodicalIF":0.7,"publicationDate":"2014-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76932728","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The calcareous tufa deposits in fresh waters are widely represented in the Iberian Peninsula, mostly related to springs from carbonate aquifers. Most studies on the geochemical modelling of the genesis of calcareous tufa consider the meteoric water percolating through the limestone aquifer is enriched in CO₂ by existing microbiological activity in soil. The new equilibrium with atmospheric CO₂ in springs and/or metabolic activity of microorganisms determines a rich variety of facies of calcareous tufa. The resulting water has a calcium bicarbonate nature. However, the hydrochemical modelling has not completely been addressed and the boundary conditions have not been taken into account in tufa systems in which soils present low CO₂ concentrations or when the nature of waters are Ca-Mg-SO₄-HCO₃. In this paper, hydrochemical results from two important examples of genesis of calcareous tufa are presented: Jucar river (Valdeganga - Presa de la Central Hidroelectrica del Bosque) and Guadiana Alto river (Ruidera pools). These results are also compared with other kart spring waters recently studied in the area. The water nature of Jucar river and Ruidera aquifers shows clearly a Ca-Mg-SO₄-HCO₃ facies. The hydrochemical interpretation cannot exclusively be explained using the CO₂–H₂O– calcite system, which has widely been used in studies of precipitation rates and paleoclimatic records of calcareous tufa or Karstification reactions of limestone aquifers. In this review, we evaluate the dedolomitization and gypsum dissolution, which are independent of partial pressure of CO₂, and kinetics and sustainability of processes in terms of genesis of tufa systems. We also consider other CO₂-dependent reactions such as the calcification gypsum and dissolution and precipitation of calcite by mixing waters. This explains the nature of waters from dolomite-gypsum aquifers and also their great generator potential of tufa systems, and refuses the interpretation based exclusively on the presence of humic acid-rich soils, not very common in arid and semi-arid areas. Finally, we examine mixing waters in multi-layered or compartmentalized seasonally aquifers, which can produce waters that develop calcareous tufa.
淡水中的钙质凝灰岩矿床在伊比利亚半岛广泛存在，主要与碳酸盐含水层的泉水有关。钙质凝灰岩成因的地球化学模拟研究大多认为，通过石灰岩含水层渗透的大气水通过土壤中存在的微生物活动富集了CO 2。与春季大气CO₂和/或微生物代谢活动的新平衡决定了丰富多样的钙质凝灰岩相。得到的水具有碳酸钙的性质。然而，水化学模型还没有完全解决，并且在土壤具有低CO₂浓度或水的性质为Ca-Mg-SO₄-HCO₃的凝灰岩系统中没有考虑边界条件。本文介绍了两个钙质凝灰岩成因的重要实例:juar河(Valdeganga - Presa de la Central Hidroelectrica del Bosque)和Guadiana Alto河(Ruidera pools)的水化学结果。这些结果还与该地区最近研究的其他卡丁车泉水进行了比较。juar河和Ruidera含水层的水性质明显表现为Ca-Mg-SO₄-HCO₃相。水化学解释不能完全用CO₂- h₂O -方解石体系来解释，该体系已广泛用于研究降水率和钙质凝灰岩的古气候记录或石灰石含水层的岩溶反应。本文从凝灰岩体系的成因出发，对不受co2分压影响的脱白云石化和石膏溶解过程及其动力学和可持续性进行了评述。我们还考虑了其他依赖CO₂的反应，如石膏的钙化和通过混合水溶解和沉淀方解石。这解释了白云石-石膏含水层的水的性质，以及它们巨大的凝灰岩系统的产生潜力，并拒绝了完全基于富含腐植酸的土壤的存在的解释，这在干旱和半干旱地区并不常见。最后，我们研究了多层或分区季节性含水层中的混合水，这些水可以产生发育钙质凝灰岩的水。
{"title":"Revisión de los modelos hidrogeoquímicos de génesis de tobas calcáreas","authors":"S. Ordóñez, D. Benavente","doi":"10.3989/EGEOL.41753.325","DOIUrl":"https://doi.org/10.3989/EGEOL.41753.325","url":null,"abstract":"The calcareous tufa deposits in fresh waters are widely represented in the Iberian Peninsula, mostly related to springs from carbonate aquifers. Most studies on the geochemical modelling of the genesis of calcareous tufa consider the meteoric water percolating through the limestone aquifer is enriched in CO₂ by existing microbiological activity in soil. The new equilibrium with atmospheric CO₂ in springs and/or metabolic activity of microorganisms determines a rich variety of facies of calcareous tufa. The resulting water has a calcium bicarbonate nature. However, the hydrochemical modelling has not completely been addressed and the boundary conditions have not been taken into account in tufa systems in which soils present low CO₂ concentrations or when the nature of waters are Ca-Mg-SO₄-HCO₃. \u0000In this paper, hydrochemical results from two important examples of genesis of calcareous tufa are presented: Jucar river (Valdeganga - Presa de la Central Hidroelectrica del Bosque) and Guadiana Alto river (Ruidera pools). These results are also compared with other kart spring waters recently studied in the area. The water nature of Jucar river and Ruidera aquifers shows clearly a Ca-Mg-SO₄-HCO₃ facies. The hydrochemical interpretation cannot exclusively be explained using the CO₂–H₂O– calcite system, which has widely been used in studies of precipitation rates and paleoclimatic records of calcareous tufa or Karstification reactions of limestone aquifers. In this review, we evaluate the dedolomitization and gypsum dissolution, which are independent of partial pressure of CO₂, and kinetics and sustainability of processes in terms of genesis of tufa systems. We also consider other CO₂-dependent reactions such as the calcification gypsum and dissolution and precipitation of calcite by mixing waters. This explains the nature of waters from dolomite-gypsum aquifers and also their great generator potential of tufa systems, and refuses the interpretation based exclusively on the presence of humic acid-rich soils, not very common in arid and semi-arid areas. Finally, we examine mixing waters in multi-layered or compartmentalized seasonally aquifers, which can produce waters that develop calcareous tufa.","PeriodicalId":50496,"journal":{"name":"Estudios Geologicos-Madrid","volume":"115 1","pages":"013"},"PeriodicalIF":0.7,"publicationDate":"2014-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88212453","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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