Mesozoic-Cenozoic landscape evolution of NW Mozambique recorded by apatite thermochronology

Bicca, Marcos Müller; Jelinek, Andréa Ritter; Philipp, Ruy Paulo; Jamal, D.

doi:10.1016/j.jog.2019.02.001

Cited by 6 publications

(7 citation statements)

References 55 publications

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“…The Zomba, Lower-Shire, and Nsanje grabens define a system of three contiguous active rift basins that extend between the southern Malawi and central Mozambique regions of EARS's magma-poor southern branch (Figure 2). Thermochronological modeling suggests that the border faults have been active since the Late Oligocene -Early Miocene, with a possible onset of Cenozoic rifting as early as the Eocene (Bicca et al, 2019;Ojo et al, 2022a). Current geodetic extension rates in the region is ca.…”

Section: Rift Structure and Tectonic Historymentioning

confidence: 99%

Rapid Versus Delayed Linkage and Coalescence of Propagating Rift Tips

Kolawole¹,

Xue²,

Dulanya³

2023

Preprint

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The tectonic interaction, linkage, and coalescence of propagating isolated rift segments create a through-going along-axis rift floor without which a continental break-up axis cannot develop.However, prior to linkage, interacting rift segments are separated by a topographic basement-high (rift interaction zone, RIZ) which is progressively dismembered and down-thrown by the lateral propagation of rift tip faulting and their hanging wall subsidence. Here, we explore the evolution of the Middle-Shire and Nsanje RIZs located along three slowly extending (~2.2 mm/yr) contiguous propagating rift segments: the southern Malawi Rift, Lower-Shire Graben, and the Nsanje Graben, East Africa. The Middle-Shire RIZ is an overlapping-oblique RIZ in which the NNE/N-trending Malawi Rift is propagating into the shoulder of the NW-trending Lower-Shire Graben, whereas the Nsanje RIZ is a tip-to-tip oblique RIZ in which the Lower-Shire Graben has propagated into the tip of the N-trending Nsanje Graben. These rift zones provide non-volcanic natural examples to explore tectonic strain localization on rift tips and syn-rift RIZ surface processes. We use a landscape evolution model with implemented fault displacement fields of two contiguous RIZs with contrasting geometries, to simulate their geomorphic evolution, and apply a static stress model to evaluate the stress transfer patterns during RIZ evolution. The model results successfully reproduce natural observations in the study area, in which, with progressive extension and tip growth, the Middle-Shire RIZ maintains minor basement down-throw and an unequilibrated axial stream profile, which contrasts the widespread basement burial and equilibrated axial stream profile across the Nsanje RIZ.Modeled static stress distribution predict compounding stress concentrations at tip-to-tip RIZs, favoring brittle strain localization and rift coalescence, and stress relaxation at overlapping oblique RIZs, favoring stalled rift coalescence. We argue that RIZ geometry strongly influences the pace of rift coalescence by modulating the spatial distribution of tectonic stresses necessary to promote riftlinking deformation and the associated surface processes.

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Section: Rift Structure and Tectonic Historymentioning

confidence: 99%

Rapid Versus Delayed Linkage and Coalescence of Propagating Rift Tips

Kolawole¹,

Xue²,

Dulanya³

2023

Preprint

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“…Importantly, this implies that the Nyika Plateau was an isolated, elevated feature by the Triassic, at least in the surrounding southern, northern, and eastern regions. Our data suggest that the topography along (Alessio et al, 2019;Bicca et al, 2019;Daszinnies, 2006;Emmel et al, 2011;Fernandes et al, 2015;Mackintosh et al, 2017;Mackintosh, Kohn, Gleadow, & Belton, 2019;Mackintosh, Kohn, Gleadow, & Gallagher, 2019;Mortimer et al, 2016;Noble, 1997;van der Beek et al, 1998). Cooling rates (∆T/∆t) are displayed at 5 Ma intervals from 400 Ma onward.…”

Section: Permo-jurassic Thermal History: Karoo Rifting and Nyika Form...mentioning

confidence: 56%

“…Data from previous studies suggest that Cretaceous cooling is likely a wide‐scale event as it is apparent in many LTT data sets (Figure 9), such as in northern Malawi and Tanzania (Kasanzu et al., 2016; van der Beek et al., 1998), Zambia (Alessio et al., 2019), southern Malawi (Daszinnies et al., 2008; Eby et al., 1995), Mozambique (Bicca et al., 2019; Daszinnies et al., 2009; Emmel et al., 2011, 2014), Zimbabwe (Belton & Raab, 2010; Mackintosh, Kohn, Gleadow, & Belton, 2019), and the South African Plateau (Wildman et al., 2017). Evidence for km‐scale uplift in the Cretaceous is also recorded in various central African cratons (e.g., the Congo Craton, Alessio et al., 2019 and the Tanzanian Craton, Noble et al., 1997; Kasanzu, 2017) and may be related to isostatic rebound in response to plume induced delamination of the lithosphere (Hu et al., 2018).…”

Section: Discussionmentioning

confidence: 97%

“… Summary of thermal history trends in the Malawi rifted zone showing main periods of cooling (Alessio et al., 2019; Bicca et al., 2019; Daszinnies, 2006; Emmel et al., 2011; Fernandes et al., 2015; Mackintosh et al., 2017; Mackintosh, Kohn, Gleadow, & Belton, 2019; Mackintosh, Kohn, Gleadow, & Gallagher, 2019; Mortimer et al., 2016; Noble, 1997; van der Beek et al., 1998). Cooling rates (∆ T /∆ t ) are displayed at 5 Ma intervals from 400 Ma onward.…”

Section: Discussionmentioning

confidence: 99%

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Development of the Nyika Plateau, Malawi: A Long Lived Paleo‐Surface or a Contemporary Feature of the East African Rift?

McMillan

Boone

Kohn

et al. 2022

Geochem Geophys Geosyst

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Northern Malawi's Nyika Plateau is a 3,700 km2 large, highly elevated (∼2,500 m) plateau located at the western margin of the Miocene‐Recent Malawi rift and the confluence of multiple Proterozoic orogenic belts. Neighboring asthenospheric upwelling in the Rungwe Volcanic Province, associated with the active East African Rift, has created similar topographic highs, leading some to speculate that the formation of Nyika could be related. Here, we present new low‐temperature data using apatite fission track, apatite (U‐Th‐Sm)/He and zircon (U‐Th)/He thermochronology to constrain the upper crustal thermal history of the Nyika region since the Devonian. The data suggest that Nyika was an isolated feature since at least the Permo‐Triassic, well before more recent rifting in Malawi, and may have developed as a horst between two large Karoo grabens, the Henga‐Ruhuhu and the North Rukuru to the southeast and northwest, respectively. Similarities between the thermal histories of Nyika and the currently separated Livingstone Plateau to the east allow for the possibility that these may have been connected in a contiguous highland prior to the formation of the intervening Neogene Malawi rift. Thermal history models for exposed Precambrian basement samples adjacent to Nyika, and once buried beneath the neighboring Karoo basins, indicate that up to 3.4 km of Permo‐Triassic section has since been eroded, with samples along the plateau not indicating burial of Karoo‐type sediment at this time. Most recent cooling histories suggest that the plateau surface continued to denude at varying degrees from the Cretaceous and reached near‐surface temperatures in the Late Paleogene‐Neogene.

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“…Over the past decades, the neotectonics and geodynamics of this large continental rift system have been the subject of considerable attention as it marks a natural laboratory, and a present‐day analogue to examine the extensional tectonics (Delvaux, 2001; Delvaux et al, 2012; Kendall & Lithgow‐Bertelloni, 2016; Scholz et al, 2020). One of the critical areas along EARS is northwestern to central Mozambique that plays a vital role on the understanding of Gondwana's evolution and amalgamation (Bicca et al, 2019; Macey et al, 2013; Meert, 2003).…”

Section: Introductionmentioning

confidence: 99%

Characterising the contemporary stress orientations near an active continental rifting zone: A case study from the Moatize Basin, central Mozambique

et al. 2022

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This paper presents the first comprehensive analysis of the present-day stress from boreholes near an active continental rifting zone in the Moatize Basin, Mozambique.The state of present-day stress in this area that is located ca. 100 km away from the Eastern African Rift System (EARS) is poorly understood, and most of our knowledge is from earthquake focal mechanisms that provide stress information from the deeper part of the lithosphere, and to a lesser extent from surface geological features in the Malawi region. Considering the limited reliability of earthquake-derived stress orientations near plate boundaries, poor coverage of low to moderate magnitude earthquakes in eastern Africa, and ambiguity about the latest activity of geological structure; other well-established methods are required to shed light on the active tectonics of EARS. In this study, we analyse stress orientation using log data from 95 vertical boreholes in a mine site to investigate the neotectonic stress pattern of the region. Analysis of 17.9 km of televiewer logs resulted in interpretation of 1188 stress-related borehole failures.The results indicate a mean regional trend of 045° ± 31° for the maximum horizontal stress (S Hmax ). Our investigation reveals that the regional state of stress in the study area is controlled by superposition of stress sources that act at very different spatial scales. The consistency between our results and predictions by plate-scale geodynamic models of stress orientations confirm that the regional pattern of stress in this area is mainly controlled by first (>500 km) and second (distances between 500 and 100 km) order stress sources (i.e., large tectonic forces and lateral density variations). However, high-resolution data used in this study reveal that third (between 100 and 1 km) and fourth (<1 km) order stress sources from stiffness contrasts, rock fabric and geological structures have a great impact on the stress perturbations at smaller and local scales.

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Mesozoic-Cenozoic landscape evolution of NW Mozambique recorded by apatite thermochronology

Cited by 6 publications

References 55 publications

Rapid Versus Delayed Linkage and Coalescence of Propagating Rift Tips

Rapid Versus Delayed Linkage and Coalescence of Propagating Rift Tips

Development of the Nyika Plateau, Malawi: A Long Lived Paleo‐Surface or a Contemporary Feature of the East African Rift?

Characterising the contemporary stress orientations near an active continental rifting zone: A case study from the Moatize Basin, central Mozambique

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