Results 71 to 80 of about 120,177 (175)

Droughts and human impact in the ancient Uaymil region of the Maya lowlands inferred from a 2800‐year sedimentary archive at Lake Kaná, Mexico

Boreas, EarlyView.
The relationship between the climate and societal transformation in Maya lowlands has long been debated, particularly the role of drought in shaping the civilization trajectory during the Classic Period. A high‐resolution, multi‐proxy, geochemical record from Lake Kaná, located in the underexplored Uaymil region of the Yucatán Peninsula in Mexico ...
Haydar B. Martinez‐Dyrzo, Priyadarsi D. Roy, Benjamin Gwinneth, Irma G. Vargas‐Martinez, Alejandro A. Aragon‐Moreno, Roger Medina‐Gonzales   +5 more
wiley   +1 more source

Radiocarbon reservoir ages and hardwater effect for the northeastern coastal waters of Argentina. [PDF]

, 2008
Accelerator mass spectrometry (AMS) radiocarbon dates were obtained for 18 mollusk shells collected alive along the Buenos Aires province coast, Argentina, over the period AD 1914–1935.
Aguirre, Marina Laura, Borel, Claudia Marcela, Gomez, Eduardo Alberto, Martinez, Daniel Emilio   +3 more
core   +2 more sources

Development of CCMb: A Low‐Mg Calcite Reference Material for In Situ Measurement of δ18O, δ13C and Selected Trace Elements

Geostandards and Geoanalytical Research, EarlyView.
Key Points Low‐Mg calcite RM developed for in situ microanalysis applications in palaeoclimatology (δ18O, δ13C; Mg, Sr m/m). New data for calcite CRM IAEA‐603 (δ18O, δ13C by SIMS and GS‐IRMS; Mg m/m). No detectable IMF effect of Mg on SIMS δ18O determinations for mass fractions < 3650 μg g‐1.
Andreas T. Hertwig, Maciej G. Śliwiński, Irene Cantarero, Richard A. Stern, Carles Fàbrega, Jakub T. Śliwiński, Thomas Ludwig, František Majs, William Nachlas, John H. Fournelle, Xavier Llovet, Rachelle B. Turnier, David Parcerisa, Anna Travé   +13 more
wiley   +1 more source

K-ar and geologic data bearing on the age and evolution of the Trans-Mexican Volcanic Belt

Geofísica Internacional, 1987
Las fechas K-Ar recientemente obtenidas y publicadas y los mapas geológicos de las partes central y occidental del Cinturón Volcánico Mexicano (CVM) proporcionan una base para examinar la evolución del volcanismo del Cenozoico tardío en la parte central ...
G. T. Nixon, A. Demant, R. L. Armstrong, J. E. Harakal   +3 more
doaj   +1 more source

Flora algal de la cuenca del río Guadalquivir: Su valor en la determinación de la ecorregionalización de la cuenca [PDF]

, 2018
In compliance with the Water Framework Directive of the European Union, we needed to diagnose the ecologic quality of the different sections of the rivers of the Guadalquivir basin. In order to establish a regional classification of the water bodies by a
Casco, Maria Adela, Fernández, María R., Martín, Gonzalo, Reyes, Isabel, Sala, Silvia Estela, Toja, Julia   +5 more
core   +2 more sources

Whole genome sequencing of historical specimens from the world's largest fungal collection yields high‐quality assemblies

New Phytologist, EarlyView.
Summary High‐throughput molecular studies of museum specimens (museomics) have great potential in biodiversity research, but fungal historical collections have scarcely been examined, leading to no comprehensive methodological assessments. Here we present a whole genome sequencing (WGS) project conducted at the Fungarium of the Royal Botanic Gardens ...
Torda Varga, Roseina Woods, Frances Pitsillides, Rowena Hill, Alona Yu Biketova, Theo Llewellyn, Brandon J. P. Shaw, Emily Hodgson, Brigid Wong, Jasmine Le, Josepha Becker, Alexander J. Bradshaw, Seth L. E. Blake, Clementine Geeves, Quentin Levicky, Lottie Goodman, Ruben L. Mole, Sidney L. Reed, M. Carly Lin, Emily Read, Keenan Harris, Raquel Pino‐Bodas, László G. Nagy, Anna Bazzicalupo, Ester Gaya   +24 more
wiley   +1 more source

Investigaciones químicas y ópticas de obsidianas geológicas y arqueológicas de México

Geofísica Internacional, 1988
Se reporta un método físico que permite caracterizar muestras arqueológicas de obsidiana y atribuirlas a sus fuentes geológicas con el objeto de reconstruir las relaciones comerciales de la época prehispánica en México.
E. Mosheim, E. Althaus
doaj   +1 more source

Reassessment of mid-Carboniferous glacial extent in southwestern Gondwana (Rio Blanco Basin, Argentina) inferred from paleo-mass transport of diamictites [PDF]

, 2013
Late Paleozoic glacial diamictites occur in many localities in western Argentina, indicating that the region was strongly affected by glaciation during the mid-Carboniferous (late Serpukhovian–early Bashkirian).
Gulbranson, Erik L., Hull, Clara, Isbell, John L., Limarino, Carlos Oscar, Marenssi, Sergio Alfredo, Meyer, Kyle, Montañez, Isabel P.   +6 more
core   +1 more source

Microbial influence on the formation and subsequent changes of vertebrate tracks: field experiments on present‐day coastal sediments

Sedimentology, EarlyView.
ABSTRACT The presence of microbial mats is often invoked to explain the good preservation of vertebrate tracks, because they can cover and biostabilize such structures. However, microbial influence on the sediment properties when the track is made and on the track characteristics has not been so thoroughly analysed.
Isabel Emma Quijada, Lucía Maisano, Jerónimo Pan, María Florencia Yorlano, Diana G. Cuadrado   +4 more
wiley   +1 more source

Morphological and structural analysis of the central sector of the Transmexican Volcanic Belt

Geofísica Internacional, 1987
En este trabajo se analiza la evolución post-Laramídica de un sector del Cinturón Volcánico Mexicano (CVM), comprendido entre los estados de Michoacán y Guanajuato. Se reconocieron las principales unidades estructurales por medio de análisis morfológicos
G. Pasquare, L. Ferrari, V. Perazzoli, M. Tiberi, F. Turchetti   +4 more
doaj   +1 more source