Crutal xenoliths in triassic lamprophyre dykes in Western Morocco : Tectonic implications for the Rheic Ocean suture

Dykes of calc-alkaline lamprophyre cutting granite of the Hercynian Jebilet Massif of the Moroccan Meseta (western Morocco) contain crustal xenoliths. The xenoliths range in composition from mafic (cognate cumulates) and upper crustal granitic rocks through gneisses to middle crustal felsic granulites. SHRIMP U­Th­Pb zircon analyses of these rocks indicate that the dykes were likely intruded during Middle Triassic times ([similar]235 Ma), whereas the xenoliths contain zircons with concordant Carboniferous­Early Permian, Neoproterozoic and Palaeoproterozoic ages (280­328 Ma, c. 540­615 Ma, 700 Ma and [similar]2000 Ma). The 280­328 Ma ages appear to record synchronous intrusive and high-grade (up to granulite facies) Variscan metamorphic events, suggesting that high-grade metamorphism may have facilitated the S-type granitic magmatism. On the other hand, the [similar]540­615 Ma, 700 Ma and 2000 Ma ages correspond with Pan-African and Eburnian orogenic events recorded in the West African Craton. In a Triassic reconstruction, Morocco is juxtaposed against Nova Scotia (Canada), and some have proposed that the basement of the easternmost terrane (Meguma terrane) is a piece of the West African craton. However, lower crustal xenoliths from Devonian dykes ([similar]370 Ma) cutting the Meguma terrane have yielded Late Devonian, Neo- and Mesoproterozoic ages (378 Ma, 575­629 Ma, [similar]880­1050 Ma and [similar]1530 Ma). The presence of [similar]1 Ga ages suggests that the basement of the Meguma terrane is Avalonian rather than West African, implying that in a Pangean reconstruction, the Rheic Ocean suture between NW Africa and Maritime Canada coincides with the Atlantic Ocean

Intraguild predation on the whitefly parasitoid eretmocerus eremicus by the generalist predator geocoris punctipes: A behavioral approach

A gravity study was conducted across the northern Oaxaca terrane and its bounding faults: the Caltepec and Oaxaca Faults to the west and east, respectively. These faults juxtapose the Oaxaca terrane against the Mixteca and Juarez terranes, respectively. The Oaxaca Fault also forms the eastern boundary of the Cenozoic Tehuacán depression. On the west, at depth, the Tehuacán valley is limited by the normal buried Tehuacán Fault. This gravity study reveals that the Oaxaca Fault system gives rise to a series of east tilted basamental blocks (Oaxaca Complex). The tectonic depression is filled with Phanerozoic rocks and has a deeper depocenter to the west. The gravity data also indicate that on the west, the Oaxaca Complex, the Caltepec and Santa Lucia faults continue northwestwards beneath Phanerozoic rocks. A major E-W to NE-SW discontinuity is inferred to exist between profiles 1 and 2. " 2014 Elsevier Ltd.",,,,,,"10.1016/j.jsames.2014.09.020",,,"http://hdl.handle.net/20.500.12104/42339","http://www.scopus.com/inward/record.url?eid=2-s2.0-84921911977&partnerID=40&md5=19f002b473bbe8dae489966860b562a3",,,,,,,,"Journal of South American Earth Sciences",,"39

Interpretation of gravity profiles across the northern Oaxaca terrane, its boundaries and the Tehuacán Valley, southern Mexico

A gravity study was conducted across the northern Oaxaca terrane and its bounding faults: the Caltepec and Oaxaca Faults to the west and east, respectively. These faults juxtapose the Oaxaca terrane against the Mixteca and Juarez terranes, respectively. The Oaxaca Fault also forms the eastern boundary of the Cenozoic Tehuacán depression. On the west, at depth, the Tehuacán valley is limited by the normal buried Tehuacán Fault. This gravity study reveals that the Oaxaca Fault system gives rise to a series of east tilted basamental blocks (Oaxaca Complex). The tectonic depression is filled with Phanerozoic rocks and has a deeper depocenter to the west. The gravity data also indicate that on the west, the Oaxaca Complex, the Caltepec and Santa Lucia faults continue northwestwards beneath Phanerozoic rocks. A major E-W to NE-SW discontinuity is inferred to exist between profiles 1 and 2. © 2014 Elsevier Ltd

Global catastrophes in earth history: an interdiciplinary conference on impacts, volcanism, and mass mortality.

Topics addressed include Cretaceous-Tertiary mass extinctions; geological indicators for meteorite collisions; carbon dioxide catastrophes; volcanism; climatic changes; geochemistry; mineralogy; fossil records; biospheric traumas; stratigraphy; mathematical models; and ocean dynamics