Late Eocene to Early Miocene Andean uplift inferred from detrital zircon fission track and U–Pb dating of Cenozoic forearc sediments (15–18°S)

Decou, Audrey; Eynatten, Hilmar von; Dunkl, İstván; Frei, Dirk

doi:10.1016/j.jsames.2013.02.003

Cited by 35 publications

(22 citation statements)

References 84 publications

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“…A transtensive tectonic arrangement for southern Perú could be consistent with tectonic rotations as proposed Roperch et al (2006). Schildgen et al (2009), Decou et al (2013), Alván et al (2015) and Alván (2015) demonstrated that Western Cordillera in the study area experimented uplift with consequente denudation and deposition of sediments (Fig. 9).…”

Section: The Origin Of Depocenters In Camaná-mollendo Basinsupporting

confidence: 80%

“…Furthermore, such authors stated that sediments of the basal part of CamA Unit (subunits A1 and A2) correspond in time to ~30 to ~25 Ma sediments of the hinterland Moquegua Group (MoqC Unit: Oligocene), according to the depositional ages proposed by Sempere et al (2004) and Decou et al (2013). Subunit MoqC1 of Moquegua Group shows dominance of piroxene, while subunit A1 shows the same minerals; however, in lower proportions.…”

Section: Deposits Of "A1+a2"mentioning

confidence: 94%

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Seismic-stratigraphic architecture of the Oligocene-Pliocene Camaná Formation, southern Peruvian forearc (Province of Arequipa)

Cruz¹,

Criales

Eynatten

et al. 2017

andgeo

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ABSTRACT. The Camaná-Mollendo Basin is an active-margin depression ~NW-SE elongated, which is located in the forearc of southern Perú and extends from the Coastal Cordillera to the Perú-Chile Trench. This basin consists of a grabens and half-graben complex, filled with deltaic and fluvial sedimentary rocks of the Oligocene-Pliocene Camaná Formation (~500 m thick). An integration of compiled onshore stratigraphic logs, reinterpreted 2D seismic offshore information, sediment provenance data, and previous zircon U-Pb geochronology on volcanic reworked ash supports a refined tectono-chronostratigraphic framework for the whole Camaná-Mollendo Basin fill. To complete this integration we needed firstly to elaborate a geological reinterpretation of seismic offshore data and highlight their most prominent features (i.e., erosive surfaces). This step allowed establishing a first correlation between onshore and offshore deposits of Camaná Formation by means of their sequence boundaries, giving as result a consistent division for Camaná Formation: (i) "CamA Unit" (coarse-grained deltas) and (ii) "CamB Unit" (fluvial deposits). CamA Unit is further subdivided into three subunits based on minor erosive surfaces (i.e., A1: Oligocene, A2: Early Miocene, and A3: Middle Miocene). CamA reflects prograding geometry (subunits A1 and A2) as well as onlapping geometry (subunit A3). CamB Unit (Late Miocene to Pliocene) consists of high-energy hyperpycnal flows composed of fluvial conglomerates in onshore, which very possibly changes to progradational deltaic in offshore. Each one of these units and subunits extends offshore and preserves similarities in depositional geometry and sequence boundaries with Camaná Formation onshore. Subunits A1 and A2 observed in offshore are grouped in this paper as "A1+A2" (Oligocene to Middle Miocene) because they show similar progradational geometry and it is difficult to differentiate them from each other. A regressive systems tract (RST) represents these subunits. These deposits reach up to ~2.5 km thick, and they are intensely affected by normal faulting associated to pinch-out depositional geometry. Strata of subunit A3 (Middle Miocene) reflect a transgressive systems tract (TST), and blanket the entire basin with fine-grained sediments. These deposits are up to ~1 km thick, being less affected by synsedimentary tectonic and show minor effects of synsedimentary tectonics. Finally, deposition of CamB Unit (Late Miocene to Pliocene) occurred during a new regressive systems tract (TST), which turned to progradational geometry similar to deltaic deposits in offshore, and according to seismic lines they are much less affected by synsedimentary faulting. Stratigraphic boundaries between "A1+A2" and A3, and between A3 and CamB observed in onshore outcrops are used here as tools to differentiate, correlate and predict the main depositional geometries in offshore. High-frequency seismic reflectors represent such boundaries and support divisions and subdivisions within Camaná Formation. These boundaries are ...

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Section: The Origin Of Depocenters In Camaná-mollendo Basinsupporting

confidence: 80%

Section: Deposits Of "A1+a2"mentioning

confidence: 94%

Seismic-stratigraphic architecture of the Oligocene-Pliocene Camaná Formation, southern Peruvian forearc (Province of Arequipa)

Cruz¹,

Criales

Eynatten

et al. 2017

andgeo

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“…The Early Triassic samples contain no pre‐Carboniferous detrital zircon grains, and only a few Precambrian detrital zircon grains were found in the Middle Triassic sample. Unimodal detrital zircon U‐Pb age patterns commonly imply a near‐arc deposition environment, such as back‐arc basin (Di Giulio et al, ; Yang et al, ; Yang et al, ) or fore‐arc basin (Decou et al, ; Degraaff‐Surpless et al, ), with the adjacent arc being the detrital source. The 280–237 Ma zircon grains from the Early‐Middle Triassic samples are mostly euhedral to subhedral (Figure ) and have oscillatory zoning with high Th/U ratios (>0.1), which indicates short distance transport from an igneous source (Corfu et al, ).…”

Section: Discussionmentioning

confidence: 99%

When Did the Paleotethys Ailaoshan Ocean Close: New Insights From Detrital Zircon U‐Pb age and Hf Isotopes

Xia

Lai

et al. 2019

Tectonics

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We present new laser ablation (LA)‐multicollector‐inductively coupled plasma mass spectrometry detrital zircon U‐Pb age and Hf isotope data of the Triassic sedimentary rocks from the eastern and western sides of the Ailaoshan suture in SW China, which separate the Indochina and South China blocks. Detrital zircon grains of the Lower‐Middle Triassic sequences from western South China show single age population of 280–237 Ma (peak at 254–251 Ma) with mainly positive εHf(t) values (+0.15 to +9.11, ~60%). The Middle Triassic samples from eastern Indochina also contain single age population of 273–236 Ma (peak at 246–242 Ma), but with mainly negative εHf(t) values (−18.95 to −1.83, ~88%). The unimodal detrital zircon age pattern and Hf isotope features suggest that the Permian‐Triassic magmatic arcs had supplied detritus for the Lower‐Middle Triassic sequences on both sides of the Ailaoshan suture. In contrast, the Upper Triassic sequences on the either side of the suture display similar polymodal age populations at 290–230, 500–400, 850–700, 1000–900, 2000–1800, and 2600–2400 Ma. This indicates a dramatic change in detrital provenance across the Middle‐Late Triassic boundary. We interpret this change to be resulted from the closure of the Paleotethyan Ailaoshan Ocean in the early Late Triassic. The ocean closure and consequent Indochina‐South China continent‐continent collision may have connected the drainage systems of the two blocks, leading to the marked similarities in their post‐Middle Triassic sedimentary provenance.

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“…(2) Large-volume ignimbrites on the western flank of the Central Andes are deposited on top of a thick sedimentary wedge that represents a major phase of (uplift and) erosion on the western flank of the Andes (Noble et al 1974;Tosdal et al 1981Tosdal et al , 1985Wörner et al 2000a;Farías et al 2005;Quang et al 2005;Pinto et al 2007;Thouret et al 2007;Wotzlaw et al 2011;Decou et al 2013). (3) Ignimbrites overly an erosional unconformity on the older, exhumed and deformed basement in the high western Cordillera.…”

Section: The Origin Of Large-volume Plateau-forming Ignimbritesmentioning

confidence: 99%

The origin and crust/mantle mass balance of Central Andean ignimbrite magmatism constrained by oxygen and strontium isotopes and erupted volumes

Freymuth

Brandmeier

Wörner³

2015

Contrib Mineral Petrol

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distinctly more radiogenic Sr and heavier O isotopes and thus contrast with older dacitic ignimbrites in northernmost Chile and southern Peru. Results of assimilation and fractional crystallization (AFC) models show that the largest chemical changes occur in the lower crust where magmas acquire a base-level geochemical signature that is later modified by middle to upper crustal AFC. Using geospatial analysis, we estimated the volume of these ignimbrite deposits throughout the Central Andes during the Neogene and examined the spatiotemporal pattern of socalled ignimbrite flare-ups. We observe a N-S migration of maximum ages of the onset of large-volume "ignimbrite pulses" through time: Major pulses occurred at 19-24 Ma (e.g. Oxaya, Nazca Group), 13-14 Ma (e.g. Huaylillas and Altos de Pica ignimbrites) and <10 Ma (Altiplano and Puna ignimbrites). Such "flare-ups" represent magmatic production rates of 25 to >70 km 3 Ma −1 km −1 (assuming plutonic/ volcanic ratios of 1:5) which are additional to, but within the order of, the arc background magmatic flux. Comparing our results to average shortening rates observed in the Andes, we observe a "lag-time" with large-volume eruptions occurring after accelerated shortening. A similar delay exists between the ignimbrite pulses and the subduction of the Juan Fernandez ridge. This is consistent with the idea that large-volume ignimbrite eruptions occurred in the wake of the N-S passage of the ridge after slab steepening has allowed hot asthenospheric mantle to ascend into and cause the melting of the mantle wedge. In our model, the older large-volume dacitic ignimbrites in the northern part of the CVZ have lower (15-37 %) crustal contributions because they were produced at times when the Central Andean crust was thinner and colder, and large-scale melting in the middle crust could not be achieved. Younger ignimbrite flare-ups further south (<10 Ma, >22°S) formed with a significantly higher crustal contribution (22-68 %) Abstract Volcanism during the Neogene in the Central Volcanic Zone (CVZ) of the Andes produced (1) stratovolcanoes, (2) rhyodacitic to rhyolitic ignimbrites which reach volumes of generally less than 300 km 3 and (3) large-volume monotonous dacitic ignimbrites of up to several thousand cubic kilometres. We present models for the origin of these magma types using O and Sr isotopes to constrain crust/mantle proportions for the large-volume ignimbrites and explore the relationship to the evolution of the Andean crust. Oxygen isotope ratios were measured on phenocrysts in order to avoid the effects of secondary alteration. Our results show a complete overlap in the Sr-O isotope compositions of lavas from stratovolcanoes and low-volume rhyolitic ignimbrites as well as older (>9 Ma) large-volume dacitic ignimbrites. This suggests that the mass balance of crustal and mantle components are largely similar. By contrast, younger (<10 Ma) large-volume dacitic ignimbrites from the southern portion of the Central Andes have Communicated by Othmar Müntener. Electronic supple...

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Late Eocene to Early Miocene Andean uplift inferred from detrital zircon fission track and U–Pb dating of Cenozoic forearc sediments (15–18°S)

Cited by 35 publications

References 84 publications

Seismic-stratigraphic architecture of the Oligocene-Pliocene Camaná Formation, southern Peruvian forearc (Province of Arequipa)

Seismic-stratigraphic architecture of the Oligocene-Pliocene Camaná Formation, southern Peruvian forearc (Province of Arequipa)

When Did the Paleotethys Ailaoshan Ocean Close: New Insights From Detrital Zircon U‐Pb age and Hf Isotopes

The origin and crust/mantle mass balance of Central Andean ignimbrite magmatism constrained by oxygen and strontium isotopes and erupted volumes

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