Person: Arribas Mocoroa, María Eugenia
Loading...
First Name
María Eugenia
Last Name
Arribas Mocoroa
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Geológicas
Department
Mineralogía y Petrología
Area
Petrología y Geoquímica
Identifiers
4 results
Search Results
Now showing 1 - 4 of 4
Item Significance of geochemical signatures on provenance in intracratonic rift basins: Examples from the Iberian plate(Geological Society of America Special Paper, 2007) Ochoa, M.; Arribas Mocoroa, María Eugenia; Arribas Mocoroa, José; Mas Mayoral, José RamónFollowing the Variscan orogeny, the Iberian plate was affected by an extensional tectonic regime from Late Permian to Late Cretaceous time. In the central part of the plate, NW-SE–trending rift basins were created. Two rifting cycles can be identified during the extensional stage: (1) a Late Permian to Hettangian cycle, and (2) a latest Jurassic to Early Cretaceous cycle. During these cycles, thick clastic continental sequences were deposited in grabens and half grabens. In both cycles, sandstone petrofacies from periods of high tectonic activity reveal a main plutoniclastic (quartzofeldspathic) character due to the erosion of coarse-grained crystalline rocks from the Hesperian Massif, during Buntsandstein (mean Qm72F25Lt3) sedimentation and during Barremian–early Albian times (mean Qm81F18Lt1). Geochemical data show that weathering was more intense during the second rifting phase (mean chemical index of alteration [CIA]: 80) due to more severe climate conditions (humid) than during the first rifting phase (mean CIA: 68) (arid climate). Ratios between major and trace elements agree with a main provenance from passive-margins settings in terms of the felsic nature of the crust. However, anomalies in trace elements have been detected in some Lower Cretaceous samples, suggesting additional basic supplies from the north area of the basin. These anomalies consist of (1) low contents in Hf, Th, and U; (2) high contents in Sc, Co, and Zr; and (3) anomalous ratios in Th/Y, La/Tb, Ta/Y, and Ni/V. Basic supplies could be related to the alkaline volcanism during Norian-Hettangian and Aalenian-Bajocian times. Geochemical composition of rift deposits has been shown to be a useful and complementary tool to petrographic deduction in provenance, especially in intensely weathered sediments. However, diagenetic processes and hydrothermalism may affect the original detrital deposits, producing changes in geochemical composition that mislead provenance and weathering deductions.Item Early Syn-Rift Evolution In the West Cameros Basin (Upper Jurassic, NW Iberian Range), Spain and Pedogenetic Calcretes In Early Syn-Rift Alluvial Systems (Upper Jurassic, West Cameros Basin), Northern Spain—Reply(Journal of Sedimentary Research, 2017) Arribas Mocoroa, María Eugenia; Mas Mayoral, José Ramón; Sacristán Horcajada, SaraFirst, we would like to highlight our appreciation of Dr. Platt's and Dr. Wright's comments and the opportunity they give us to discuss some aspects of our papers (Sacristan-Horcajada et al. 2015, 2016) improving the final state of our work.Knowledge about sedimentology of alluvial systems has had an important development in recent years, with new proposals for models in rift basins where tectonics play a predominant role (Nichols and Fisher 2007; Hartley et al. 2010; Weismann et al. 2010; Fielding et al. 2012). The differential behavior of the extensional structures during the earliest syn-rift stage (Tithonian) in the West Cameros Basin played a key role in the architecture of the various alluvial systems (Sacristan-Horcajada et al. 2015) as well as the distribution of various calcrete sequences (Sacristan-Hocajada et al. 2016). We discuss the points raised Drs. Platt and Wright in the same order they established.Item Estratigrafía(Coloquios de paleontología, 1992) Rodríguez García, Sergio; Arribas Mocoroa, María Eugenia; Comas Rengifo, María José; Peña, José Andrés de la; Falces, Santiago; Gegúndez, P.; Martínez Chacón, María Luisa; Moreno-Eiris, Elena; Perejón, Antonio; Sánchez Roldán, José Luis; Sáchez Chico, FátimaThe stratigraphic succession of Los Santos basin can be divided in three groups: a lower group composed mainly of greywackes and volcanie rocks, a middle carbonate group, and an upper siliciclastie group. SANCHEZ el uf (1988) described four lirbologie units (1-4) in the Jower part of the carbonate sediments based on five stratigraphic seetions iii tbe southern part of the basin. RODRÍGUEZ et al., in press) defined duce units, including the upper part of tbe carbonate rocks (5-6)and the upper siliciclastic rocks (7), based on six new stratigraphic sections, also in the southern area. Finally, FALCES (1991) briefly deseribed 4w lower siliciclastic unit (0), and characterized the variations of the units 1 to 7 on dic basis of several stratigraphical sections in the northern part of the basin: ihe calcareous Units 1,3,4 and 6 yielded abundant fossils and perniited a precise biostratigraplw, based mainly in foraminifers, corals and brachiopods. Sorne Goniatites, conodonts and algae provided additional data.Item Pedogenetic Calcretes In Early Syn-Rift Alluvial Systems (Upper Jurassic, West Cameros Basin), Northern Spain(Journal of Sedimentary Research, 2016) Sacristán Horcajada, Sara; Arribas Mocoroa, María Eugenia; Mas Mayoral, José RamónExceptional pedogenetic calcretes occur in the earliest syn-rift sedimentary record (Tithonian) of the west Cameros Basin. These calcretes show different types of pedogenetic facies (nodular, massive, laminar, and brecciated–pisolithic) and microfabrics: brecciated intraclasts, carbonate nodules, coated clasts and grains, etched quartz grains, rhizocretions, pedotubules and fragmented alveolar–septal structures. In addition, calcrete fragments have been observed in the conglomerate and sandy channelized deposits that form the alluvial systems, indicating the reworking of previous calcrete deposits. Calcrete facies appear organized in several sequences developed over different architectural elements in three different types of alluvial systems. The type of calcrete sequence is different depending on the architectural arrangement of each alluvial-fan system. Laminar (L (MN)–S) and brecciated–pisolithic (BP (L)–S) calcrete sequences are predominant in the alluvial sedimentary record of poorly channelized alluvial systems. These calcretes are thick, morphologically complex, and laterally continuous, due to the formation of long-term stable subaerial surfaces favored by the intermittent behavior of the alluvial systems. Massive-nodular (M (N)–S) and laminar (L (MN)–S) sequences are predominant in highly channelized alluvial systems and develop only locally in interchannel or floodplain areas where sedimentation stops temporally. Calcrete sequences in the distributive fluvial fan systems can be considered as poorly developed, being massive-nodular (M (N)–S) and nodular (N–S). After analyzing the location of these calcrete sequences in the studied record and their genesis and environmental significance, their variations can be related to different autocyclic factors such as sedimentation rate, channel network organization, texture of the host sediment, and water-table influence. Also three main allocyclic factors such as climate, tectonics, and drainage area controlled the carbonate sedimentation and therefore the development of the calcretes.