Gradientes Térmicos Crustais Das Bacias Sedimentares Na Região Amazônica

Pimentel, Elizabeth Tavares; Hamza, Valiya M.

doi:10.3997/2214-4609-pdb.197.sbgf_2216

Cited by 3 publications

(1 citation statement)

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“…Thus, considering that the source rocks would be associated with Palaeozoic deposits, the shallow depths in the basement region south of latitude 9°S reduce the prospects for preservation or adequate maturation of organic matter due to low burial. This assessment is reinforced by the occurrence of relatively high geothermal gradients, between 22 and 32°C/km in the basin northern portion, indicating favourable conditions for hydrocarbon maturation (Mathalone & Montoya, 1995; Pimentel & Hamza, 2010). On the other hand, our data demonstrate for the first time the occurrence of isolated lows in the southern portion of the basin basement (Figure 9a), which may occasionally serve as targets for hydrocarbon exploration campaigns.…”

Section: Discussionmentioning

confidence: 99%

The Acre Basin basement (NW Brazil) and the transition from the intracratonic to retroarc foreland basin system

Oliveira

Vidotti

2022

Basin Research

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The understanding of the crustal transition between orogenic zones and cratonic portions in distal regions of foreland basins has received increasing attention, but the analysis is often hampered by the sedimentary cover. Despite the peculiar location of the Acre Basin, specifically between the Amazonian Craton and the sub-Andean zone, local basement studies are still scarce due to lacking seismic data and exploratory wells. Therefore, this work aims to map basement depths, estimate crustal compositions and identify the main depocenters, structures and limits of Acre Basin using an integrated analysis to understand better the region lithospheric evolution, its relationship with the Amazonian Craton and its positioning within the Andean orogeny. For that, we used well, 2D seismic reflection, airborne and ground gravity and magnetic data as well as the EMG2008. Tilt Depth estimates indicate basement depths between 500 and 7800 m and larger sedimentary thicknesses in the northern portion. Additionally, we modelled groups of potential sources between 0.1 and 22 km and Moho depths between 26 and 37 km.Compositionally, the upper crust consists dominantly of meta-sedimentary and low-grade metamorphic rocks and granites, indicating that the sub-Andean and Acre Basins share a similar basement. Thus, there are indications that the basement of the Acre Basin is essentially formed by the Sunsás province in the Amazonian Craton. However, local differences in basement depth, magnetic susceptibility and exploratory potential led to the subdivision into Divisor and Xapuri sub-basins, north and south of the Fitzcarrald Arch, respectively. Finally, it was possible to establish the limits of the Andean orogeny influence in the Acre Basin and delimit the area of the Western Amazon Foredeep installed during the Neogene.

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Section: Discussionmentioning

confidence: 99%