High resolution magnetic, regional gravity and petrophysical characterization of the Dominican Republic tectonic domains with special focus on the Central Cordillera

Abstract

Ayala, C., et al., 2017. High resolution magnetic, regional gravity and petrophysical characterization of the Dominican Republic tectonic domains with special focus on the Central Cordillera. Boletín Geológico y Minero, 128 (3): 611-631 ISSN: 0366-0176 DOI: 10.21701/bolgeomin.128.3.005 611 High resolution magnetic, regional gravity and petrophysical characterization of the Dominican Republic tectonic domains with special focus on the Central Cordillera C. Ayala (1,2) , J. L. García-Lobón (1) , J. Escuder-Viruete (1) , C. Rey-Moral (1) , A. Pérez-Estaún (3, †) y A. Padín-Debén (4) (1) Geological Survey of Spain (IGME), C/ La Calera n. 1, 28760 Tres Cantos, Madrid. Tl.: +34 917287218, Fax: +34 917287202 c.ayala@igme.es; jl.garcia@igme.es; j.escuder@igme.es; c.rey@igme.es (2) Now visiting at the Institute of Earth Sciences Jaume Almera-CSIC, C/ Lluís Solé i Sabarís s/n, 08028 Barcelona. ABSTRACTThe aim of this study is twofold: to make a geological interpretation of available ground gravity and high resolution airborne magnetic surveys carried out over the Dominican Republic, and to define the spatial limits of key tectonic units of the Central Cordillera. Potential fields and petrophysical data allow the establishment of the spatial limits and the relationships of the key tectonic units at local and regional scale. Therefore, gravity and magnetic data have been integrated to produce models of the upper crustal structure across the Central Cordillera following corresponding geological cross-sections that have been extended in depth. Since there are no seismic or borehole data to constrain the models in our study area, modelling is based on potential field data and the analysis of the physical properties that have been measured from surface rocks (586 density and magnetic susceptibility samples). The main features of the potential fields maps are: (1) NW-SE-trending anomalies delineating the main tectonic units, which coincide with the major strike-slip fault zones that limit those units; (2) exceptional geophysical mapping examples of volcano-sedimentary units; and (3) significant anomalies due to a magmatism widely spread all over Hispaniola Island. The modelling results reveal the petrophysical heterogeneities and subsurface geometry of the tectonic units, faults and shear zones. The model shows that Tireo Fm extends up to 7 km in depth. The Duarte Complex has been modelled as a layer of c. 5-7 km in thickness beneath the Tireo Fm and the S. Juan Basin. Some of the intrusive bodies may reach depths of c. 8 km.Key words: Central Cordillera-Dominican Republic, Density, Geophysical mapping, Magnetic susceptibility, Potential field modelling.Caracterización de los dominios tectónicos de la República dominicana, con especial énfasis en la Cordillera Central, mediante datos aeromagnéticos de alta resolución, gravimetría regional y petrofísica Presente (e.g. Mann et al., 1991, 1995 (Bowin, 1975;Lewis and Draper, 1990;Mann et al., , 1995 . Contexto geológico La geología de La Hispaniola está formad...

Active Tectonics, Quaternary Stress Regime Evolution and Seismotectonic Faults in Southern Central Hispaniola: Implications for the Quantitative Seismic Hazard Assessment

“…More details of the methodology of acquisition and analysis of the potential field data are included in García Lobón and Rey Moral (2004), García‐Lobón and Ayala (2007), and Ayala et al. (2017).…”

“…In contrast, long wavelength gravity anomalies between −60 and 14 mGal (dark and light blue tones) characterize the Cibao basin, the southern sector of the Cordillera Central (PB) and the San Juan‐Azua basin. These areas comprise silicilastic and carbonate rocks of the late Cenozoic sedimentary cover, with average densities around 2.55 g/cm 3 (Ayala et al., 2017). These negative anomalies present a smooth texture and are elongated in the NW‐SE to WNW‐ESE direction, subparallel to the positive anomalies of the Cretaceous basement.…”

Present‐Day Caribbean‐North American Oblique Convergence Through the Ocoa‐Bonao‐La Guacara Fault Zone, Southern Central Hispaniola: A Transition Zone Between Oceanic Subduction and Arc‐Oceanic Plateau Collision

“…The orientation of the regional magnetic field showing NW to WNW-trending subparallel bands draw the large-scale structure of southern central Hispaniola (Ayala et al, 2017). In detail, the eastern Cordillera Central and surrounding areas can be subdivided into major textural patterns in the reduced to the pole (RTP) and first-vertical-derivative magnetic grids (VDM; Figure 4).…”

“…The geophysical data comes from the magnetic and radiometric flight carried out in the context of the EU SYSMIN Project in the Dominican Republic. The methodology of acquisition and analysis of the potential field data is explained in García Lobón and Rey Moral ( 2004), García-Lobón and Ayala (2007) and Ayala et al (2017), as well as in the Supporting Information S1. Because the total magnetic intensity map responds to the sum of magnetic fields contributed by different crustal lithological units and structures, it is not possible to quantitatively classify the anomalies of the studied area using the total magnetic field.…”

<p><strong>A unique flower in Miocene amber sheds new light on the evolution of flowers</strong></p>

“…Although developmental and genetic studies support it (Wang et al, 2011;Zhang, 2019), almost none of fossil flowers (Poinar & Chambers, 2005;Poinar et al, 2007Poinar et al, , 2008aPoinar et al, , b, 2016Poinar, 2017;Poinar & Rasmussen, 2017;Fu et al, 2018;Liu et al, 2018;Manchester et al, 2018; favors this belief. Dominican amber (15-20 Ma, mid-Miocene) is famous for its diverse fossil inclusions, including some of flowers (Iturralde-Vinent & MacPhee, 1996;Iturralde-Vinent, 2001;Sherwin, 2006;Poinar, 2010Poinar, , 2016aAyala et al, 2017;Ross, 2019).…”