Provenance of Carboniferous-Permian sedimentary units in southern Mexico: evidence for peri-arc basin evolution during the Pangea assembly

ABSTRACT The Oaxacan Complex Carboniferous-Permian sedimentary cover in southern México records provenance shifts through time, reflecting the collision between Gondwana and Laurentia to amalgamate Pangea. The integration of petrological analysis and LA-ICP-MS U-Pb zircon geochronology from Santiago, Ixtaltepec and Yododeñe formations compared with adjacent terranes suggests that: (1) during the Early Mississippian, the Santiago Formation received sediments mainly from local sources such as the Oaxacan Complex and Tiñu Formation, with minor contributions from adjacent peri-Gondwana sources. The magmatic activity may have started during this time (~359–346 Ma) (2) during the Late Mississippian (Ixtaltepec Formation), detrital zircon grains of Ediacaran-Cambrian age are dominant, derived from sediments either related to the Pan-African/Brasiliano orogeny or the opening of the Iapetus Ocean; (3) during the Late Mississippian-Middle Pennsylvanian, intercalated marine volcaniclastic sandstone (Ixtaltepec Formation) provides the first record of Carboniferous arc-related volcanism reported in southern Mexico, dated between 330 and 308 Ma; (4) the early Permian Yododeñe Formation records the exhumation and erosion of the sedimentary cover during the final stage of Pangea assembly. Rhyodacitic subvolcanic sills and lavas dated at ~282–270 Ma are present throughout the succession. Volcanism and ca. 360–308 Ma detrital zircon grains could be associated with a Carboniferous magmatic arc formed by subduction of the Rheic oceanic plate beneath Gondwana. Slightly younger detrital zircon and subvolcanic rocks dated at ~300–270 Ma are linked to a western Pangea arc developed in response to the subduction of the Paleo-Pacific Ocean following Pangea assembly. Our results suggest that the Carboniferous-Permian units were deposited in a peri-arc basin, sharing sediment provenance with the Maya and Coahuila blocks, the Sierra de Juárez Complex, and northwestern South America.


Introduction
The final stage of western Pangea assembly is associated with the closure of the Rheic Ocean during the Pennsylvanian-early Permian time (e.g.Nance et al. 2012).Subduction along the northern margin of Gondwana developed volcanic arcs and associated marine peri -arc basins (Poole et al. 2005), whose strata would record the transition from oceanic subduction to the diachronous collision between Gondwana and Laurentia to form Pangea.
Carboniferous-Permian magmatism and sedimentation in the middle America terranes (formerly part of northwestern Gondwana and considered peri-Gondwanan; Figure 1a) have been interpreted to record: 1) subduction and subsequent closure of the Rheic oceanic plate along the northern margin of Gondwana (e.g.Coombs et al. 2020;Ramirez-Fernández et al. 2021;Casas-Peña et al. 2021) or 2) subduction of a proto-Pacific crust beneath the western (Laurentia and Gondwana) margin of Pangea (e.g.Kirsch et al. 2012;Ortega-Obregón et al. 2014).Basins formed along these convergent plate margins are characterized by synsedimentary magmatic activity, rapid changes in facies, and temporal and spatial variations in sediment provenance (Cawood et al. 2012).
According to current palaeogeographic models, Oaxaquia in southeastern Mexico is one of the peri-Gondwana continental terranes (Figure 1a,b).Mesoproterozoic rocks of southern Oaxaquia (Oaxacan Complex; Figure 1b) are unconformably overlain by an unmetamorphosed Carboniferous-Permian succession that encloses igneous bodies of unknown age (Pantoja- Alor 1970; Centeno-Garcia and Keppie 1999).The sedimentary provenance of this succession provides the opportunity to unravel the paleotectonic evolution that likely involved the subduction of oceanic crust, the formation of different volcanic arcs, and the final collisional stage leading to the Pangea assembly.However, previous studies only have focused on the abundant Carboniferous fauna (Navarro-Santillán et al. 2002;Villanueva-Olea et al. 2011;Torres Martínez and Sour Tovar 2016;Torres-Martínez and Sour-Tovar 2018), and there are limited data regarding sediment provenance (e.g.Gillis et al. 2005), basin evolution, and correlation between the Oaxaquia block and its adjacent continental blocks according to the relative palaeogeographic localization and sediment supply.

Geological setting
Precambrian and Palaeozoic blocks in Mexico, including their Proterozoic basement and early Palaeozoic cover, are considered to be of peri-Gondwanan origin (e.g.Oaxaquia, Maya Block, Acatlán Complex, and Coahuila Block; Figures 1a and 2).Based on palaeontological, geochemical, and palaeomagnetic data, they have been interpreted to have formed along the northwestern margin of Gondwana during the late Neoproterozoic-early Palaeozoic (e.g.Robison and Pantoja-alor 1968;Centeno-García and Keppie, 1999;Keppie 2004;Murphy et al. 2005Murphy et al. , 2006;;Landing et al. 2007;Ortega-Gutiérrez et al. 2018); later, they were attached to the southern Laurentia margin during Rheic Ocean closure and Pangea assembly during the Mississippian-Permian at about ~330-250 Ma (e.g.Nance et al. 2012).Therefore, Palaeozoic tectonic evolution is recorded by the Carboniferous-Permian sedimentary succession that overlays the Mesoproterozoic basement of Oaxaquia.
The Santiago and Ixtaltepec formations are intruded by rhyodacitic hypabyssal sills and dykes(Figures 3 and  4c).The contacts between the Tiñu, Santiago, and Ixtaltepec formations generally are westward-dipping shear zones with slaty cleavage.Such shear zone is also exposed in the upper part of the Ixtaltepec Formation in the Jaltepetongo area (Figure 3c,d).Centeno-Garcia and Keppie (1999) observed these tectonic contacts, as well as a locally, transitional contact between the Santiago and Ixtaltepec formations is observed.In the Santiago Ixtaltepec area, the Ixtaltepec Formation is overlain by the Yododeñe Formation.

Yododeñe formation (Permian-Cretaceous?)
The Yododeñe Formation consists of ~400 m-thick centimetre-thick intercalated beds of sandstone, siltstone, and shale.It also includes a massive metric-thick, clastsupported pebble to cobble polymictic conglomerate.Clasts of conglomerate are composed of sandstone, fossiliferous limestone, and volcanic fragments.The top 50 m of the upper interval of the Yododeñe Formation is made up of rhyodacite lavas (Figure 4d).The Yododeñe Formation has been considered of Permian to Cretaceous age (Pantoja-Alor 1970; Flores de Dios-Gonzaléz et al. 2003), deposited in an alluvial fan or fan delta systems (Flores de Dios-Gonzaléz et al. 2003;Silva-Pineda et al. 2003).

Carboniferous-permian arcs
Carboniferous and Permian magmatic arcs in Gondwana were a potential source of sediment to peri-arc basins on peri-Gondwana terranes (e.g.Lopez 1997;Rosales-Lagarde et al. 2005;Kirsch et al. 2012;Casas-Peña et al. 2021).Mississippian magmatism has been documented in several peri-Gondwana terranes (Figures 1 and 2), including the Aserradero Rhyolite (~340-347 Ma) in northern Oaxaquia (Stewart et al. 1999;Ramírez-Fernández et al. 2021); Peperite La Pezuña from the Las Delicias arc (~330 Ma) in the Coahuila Block (Lopez 1997) and granitoids in the Maya Block (~326 Ma; Zhao et al. 2020).Younger Early Pennsylvanian granitoids were also reported in Los Altos Cuchumatanes in Guatemala (312-316 Ma;Solari et al. 2010).Igneous rocks are related to a volcanic arc (referred to the northern Gondwana arc; Tian et al. 2022a) developed in northern Gondwana as a result of the subduction of the Rheic oceanic plate beneath Gondwana and the anatexis produced by asthenospheric upwelling resulting from slab breakoff (Zhao et al. 2020).
Late-Pennsylvanian-early Permian magmatism is reported along Mexico (Figures 1 and 2), mostly in granitoids on the western Gulf of Mexico (Coombs et al. 2020)

Sampling
Twenty-seven samples of variable grain-sized sandstone, volcaniclastic sandstone, and rhyodacitic subvolcanic intrusives from the Santiago Ixtaltepec and Jaltepetongo areas were collected for petrographic analysis and U-Pb dating.The sample locations are indicated in the map and stratigraphic sections of Figure 3 and Supplementary Table 1.Only one sample of volcaniclastic sandstone (Six21-5) and one of foliated sandstone (Yuc21-1), both from the Ixtaltepec Formation, were collected outside the sections shown in Figure 3b-d.
Thin sections were stained with potassium rhodizonate for K-feldspar recognition.Between 300 and 400 points were counted using the Gazzi-Dickinson method (Gazzi 1966;Dickinson 1970).Twenty categories were defined, and point-counting data were plotted on ternary diagrams for the sandstone descriptive classification proposed by Garzanti (2016).Tables A and B of the Supplemental Files illustrate the categories and detailed point-counting results.For dominantly tuffaceous rocks (Supplementary Table 1), a non-genetic nomenclature was used (Fisher 1961), independent of either a primary pyroclastic origin or the reworking of pyroclastic material.Accordingly, 'volcaniclastic' refers to clastic volcanic material regardless of its origin.
Zircon separation was performed using conventional techniques including crushing, grinding, sieving, panning, Frantz isodynamic magnetic separation, and heavy liquids.Approximately 120 zircon grains were randomly selected from each sample using a binocular microscope and handpicking techniques.Grains were mounted in epoxy resin, polished, and imaged by cathodoluminescence (CL) using an ELM-3 R luminoscope.U-Pb analysis was performed using laser ablation inductively coupled plasma mass spectrometer (LA-ICPMS) employing aThermo ICap Qc quadrupole ICPMS, coupled with a Resolution M050 excimer laser workstation in the Laboratorio de Estudios Isotópicos (LEI), Centro de Geociencias UNAM.The analytic procedure is described in Solari et al. (2015).The standard zircons used were 91,500 (1065.4± 0.6 Ma, Wiedenbeck et al. 1995) and Plešovice (337.13 ± 0.37 Ma, Sláma et al. 2008).The data reduction process was performed using Iolite 4 software (Paton et al. 2010(Paton et al. , 2011)).The VizualAge data reduction scheme of Petrus and Kamber (2012) for Iolite was employed to calculate zircon elemental concentrations and U-Pb ratios, ages, and 2SE uncertainties.Common Pb correction was not applied because the 204 Pb signal is interfered with the isobar 204 Hg from carrier gasses.To define the 'Best age', we used 207 Pb/ 206 Pb ages for zircon grains older than 1.4 Ga and 206 Pb/ 238 U ages for zircons younger than 1.4 Ga (Spencer et al. 2016).A concordia filter was employed, excluding discordant results outside −3< dc< 10%.To calculate mean crystallization ages, we further filtered data eliminating those slightly younger and discordant analyses, probably due to slight Pb loss after crystallization.Details of the analytical methodology and analytical results are given in Table C of the Supplemental Files.For detrital samples, maximum U-Pb depositional ages (MDA) were calculated employing the weighted mean of the youngest concordant cluster of 3 or more grains that overlap in age at 2σ (YGC2σ; Dickinson and Gehrels 2009), with a mean square weighted deviation (MSWD) of ~1 (Coutts et al. 2019).Similarly, for volcaniclastic (tuff) and subvolcanic rocks, we used the YGC2σ to calculate the crystallization age of the magmatic sources.
Only filtered analyses were used to construct Kernel density estimates plots (KDEs).Visual comparison of detrital zircons presented here uses KDE with bandwidth and histogram bin width of 50 Ma and 100 Ma, respectively.Likewise, we applied a multidimensional scaling diagram (MDS; Vermeesch 2013) to concordant U-Pb ages from the studied sandstones, integrating our data with available data of possible source rocks in other peri-Gondwanan terranes.Additionally, we added synthetic samples plotted in the MDS diagram for better visualization of possible provenance trends through time, which may be related to changes in tectonic settings (Spencer and Kirkland 2016).

Sandstone petrography and modal composition
Sandstone samples from the three studied formations are fine-to medium-grained sandstones mainly composed of monocrystalline quartz, feldspar, and subordinated volcanic, metamorphic, and sedimentary (siltstone and limestone) lithics (except for the Yododeñe Formation).
Based on petrographic observations, samples show abundant illite replacing feldspars; overgrowth of quartz, calcite, dolomite, siderite, and clay cement.These features indicate that the sandstones are highly altered by diagenesis or hydrothermal fluid circulation.However, the framework quartz grains include both mono-and polycrystalline grains; the latter has a phaneritic texture that displays solid-state deformation and recrystallization structures such as undulatory extinction, grain boundary migration, oriented crystals, and mosaic texture with triple-junction.Feldspars consist of orthoclase and twinned plagioclase, both commonly altered to clay minerals.Metamorphic lithics are mostly metapelitic fragments of grades 2 and 3 of the greenschist facies (Garzanti and Vezzoli 2003).Volcanic lithics are dominantly lathwork and microlithic composed of plagioclase phenocrysts and microlites set in a groundmass of devitrified glass.
Detrital modes calculated for the sandstones from the three formations demonstrate a compositional variability along the sections (Figure 6).

Ixtaltepec formation
Three and two samples were collected in the Las Pulgas section of Santiago-Ixtaltepec (Figure 3a,b) and Jaltepetongo areas (S1a and S3a sections; Figure 3c,d), respectively.Texturally, they are fine-to-medium-grained and moderately sorted sandstone, displaying subangular to subrounded grains cemented by calcite and amorphous silica.In the QFL diagram (Figure 6), samples from both areas show a wide compositional range that varies from litho-feldspatho quartzose and quartzfelspathic sandstones to quartzose sandstones, from bottom to top of the stratigraphic section.The scattering is due to variability in the quartz content (80-30% of the total grains), and feldspar (43-4%), metamorphic (12-1%), volcanic (8-1%), and sedimentary lithic grains (7-1%).Heavy minerals include zircon, rutile, tourmaline, glauconite, and chlorite in minor proportion (< 1%).Metamorphic lithic grains are mainly metapelitic fragments of grades 1, 2, and 3 (Figure 5e).Sedimentary lithic grains are claystone and siltstone fragments and limestone clasts containing fossils of brachiopods, crinoids, and bryozoans (Figure 5f).Volcanic grains were identified as felsitic, lathwork, and microlitic fragments (Figure 5g).The compositional variability is demonstrated in two samples from the lower part of the Santiago area, which contain more quartz and metamorphic fragments than the one sample from the middle stratigraphic section, which is richer in feldspar and sedimentary lithics-rich grains (Figure 6 see numbers 1, 2 and 3).Similarly, sandstones from the Jaltepetongo area have more feldspar grains and volcanic fragments in the lower part of the section (Figure 6; numbers 1 and 2) but are more quartzrich in the upper part (Figure 3; number 3).

Yododeñe formation
The sandstones from the Yododeñe Formation are medium-to coarse-grained, and well-sorted, with subangular grains cemented by calcite, haematite, and clay matrix.
The composition ranges from feldspatho-quartzose lithic to litho-quartzose (Figure 6).Thus, the sandstone composition differs from those of the samples from the Santiago and Ixtaltepec formations.Framework grains are quartz (78-39%), lithic fragments (45-13%), and minor plagioclase and feldspar (15-5%).Quartz is present as monocrystalline grains (56-27%) that locally show needle-shaped rutile inclusions (Figure 5h).Sedimentary lithic grains are ubiquitous in all samples, mainly consisting of carbonate and claystone fragments showing plastic deformation and forming a pseudo matrix between grains (Figure 5h,i).In the ternary plot, sandstone composition modes show an increase in both quartz grains and sedimentary lithic fragments from the bottom to the top of the section (Figure 6).

Santiago formation (Tournaisian-Visean)
Zircons from coarse-grained sandstone of the Santiago Formation are mainly rounded with some elongated, prismatic grains.CL images show either low or bright, patchy and homogeneous textures, with some crystals showing oscillatory zoning and inherited xenocrysts (Appendix A).A total of 106, 111, and 95 zircon grains from samples Yux21-1, Lpix20-4 and Lpix20-6, respectively, were analysed, 40 of which (11, 13 and 16 grains, respectively) were discarded based on filtering criteria (Figure 7a-c).A main age population spans from ~850-1340 Ma (44-86% of the total concordant grains), with prominent age distribution at ~1014-1217 Ma.A minor population defines an age range of ~1529-1650 Ma (8-12% of the total grains) with a peak at ~1560 Ma.A smaller age group of six (8%) grains produced peaks at 441 Ma (Figure 7c).Two youngest grains yielded ages of 240 and 320 Ma.

Ixtaltepec formation (Serpukhovian-Moscovian)
Zircon grains separated from all samples show variable morphologies, varying from rounded to euhedral prismatic grains (Appendix A).All samples from the Ixtaltepec Formation have age distribution somewhat different from the Santiago Formation samples.The main difference is the appearance of the Mississippian ages (Figure 7d-h) and a significant Cambrian-Neoproterozoic group (Figure 7d).A total of 101 zircon grains were separated and analysed from sample Fix21-4 collected in the Santiago Ixtaltepec area, of which 93 (92% of total grains) passed the discordia filters (Figure 7d).Three dominant groups in the range of ~300-370 Ma (11 grains; 12% of total), ~440-830 Ma (48 grains; 52%), and ~960-1150 Ma (20 grains; 21%) define age peaks at 359, 535 and 1018 Ma, respectively.A minor zircon group (8 grains; 9%) of ~1500-1960 Ma represents a density peak at 1887 Ma.Subordinated grains (<6%) yielded ages of 1280-  show ages younger than 500 Ma.Plots were constructed using 206 Pb/ 238 U ages for zircon grains younger than 1.4 Ga, and 207 Pb/ 206 Pb ages for zircon grains older than 1.4 Ga.Error ellipses are at the 2σ level.Kernel Density Estimator (KDE) diagrams from Isoplot R software package programme of Vermeesch (2018) using 50 Ma bandwidth and histogram with 100 Ma bin width.YGC2σ = weighted mean age of the youngest cluster of three or more grain ages (n ≥ 3) overlapping in age at 2σ, representing the maximum depositional age (Dickinson and Gehrels 2009).Empty ellipses are analysed with 10% normal and 3% reverse discordance, which were discarded from statistical analysis.

Yododeñe Formation (Artinskian-Kungurian)
One sample (Yod21-2) of litho-quartzose sandstone from the Yododeñe Formation contains subrounded zircon grains with low CL and brighter euhedral grains Figure 8. Concordia diagrams and weighted mean ages of analysed volcaniclastic and igneous rocks interbedded in/or intruding Carboniferous-Permian sedimentary units.Concordia diagrams and weighted means were calculated using IsoplotR (Vermeesch 2018).Insets show zircon ages used in the calculation of crystallization ages from the youngest cluster of three or more ages (n ≥ 3) overlapping in age at 2σ (Dickinson and Gehrels 2009).Brown ellipses are analyses used in the age calculation.Empty ellipses with dashed lines were excluded after filtering.

U-Pb zircon ages from Carboniferous-Permian volcaniclastic and subvolcanic rocks
To further constrain the depositional ages and provenance in the detrital zircon of Carboniferous and Permian successions, we analysed four samples from volcaniclastic rocks intercalated within the Ixtaltepec Formation in the Santiago Ixtaltepec and Jaltepetongo areas (samples Fix21-3, Six21-5, SIJ20-3, and Tato21-1; Supplementary Table 1 and Figure 3).Zircon grains from volcaniclastic siltstone of rhyodacitic composition (samples Fix21-3 and Six21-5) are euhedral and display high-CL oscillatory zoning typical of magmatic crystallization.
Thirty-five analysed zircons from sample Fix21-3 yielded ages between 300 and 346 Ma (Figure 8a).A consistent group of 23 grains provides a weighted mean of 327.7 ± 1.9 Ma (MSWD = 1.1), which best approximates the depositional age.One hundred and one zircon grains were analysed from sample Six21-5, 12 of which were excluded after filtering (Figure 8b).The remaining eighty-nine analyses yielded ages ranging from 314 to 1260 Ma.Fourteen older zircon ages of ~900-1260 Ma are likely inherited from basement rocks of the Oaxacan Complex.Eleven grains define an age of 314.5 ± 2.1 Ma (MSWD = 0.93, n = 11) for this volcaniclastic siltstone, representing an approximate age for the volcanic event.
One hundred zircons were analysed from sample SIJ20-3, 15 of which failed the discordia filter (Figure 8c).Twenty-five rounded zircon grains yielded Neo-Mesoproterozoic ages, interpreted as inherited from basement rocks.Sixty-four younger grains yielded ages between 296 and 389 Ma, 31 of which define a weighted mean age of 330.5 ± 1.0 Ma (MSWD = 1.23, n = 31), considered to be close to the depositional age.
Thirty-five euhedral zircon grains were analysed from sample Tato21-1 (Figure 8d), and range in age from ~271 to 345 Ma.The 16 youngest concordant zircons define a weighted mean age of 330.2 ± 2.2 Ma (MSWD = 1.06, n = 16) that is interpreted to date the volcanism.
Samples from rhyolitic-dacitic hypabyssal sills and lavas were also analysed to constrain the age of magmatism that post-dates the deposition of Santiago and Ixtaltepec formations and constrain to the depositional age of the Yododeñe Formation (Figures 3 and 4c,d).
Sample Jal21-10 was collected from a rhyolitic-dacitic sill intruding the Ixtaltepec Formation in the Jaltepetongo area (Figure 3c-d).Thirty-five grains were analysed, and nine were discarded after discordance filtering (Figure 8e).A cluster defined by the eleven youngest analyses yields a crystallization age of 272.6 ± 2.6 Ma (MSWD = 1.23, n = 11).Sample Yod21-5 was obtained from the rhyodacitic body exposed in the upper part of the Yododeñe section (Figures 3b and 4d).Zircon grains in this sample are euhedral with high-CL oscillatory zoning.Thirty zircon grains were analysed, resulting in concordant ages ranging from 258 to 299 Ma (Figure 8f), with only four grains discarded.The mean age for the youngest cluster of 13 grains is 282.3 ± 1.9 Ma (MSWD = 1.35, n = 13) and interpreted as the rhyodacite crystallization age.

Multidimensional Scaling of the Carboniferous -Permian successions
Detrital zircon ages comprise a variety of age spectrums along sections (Figure 7d-i).MDS plot reproduces the variation, plotting samples in diverse Groups 1, 2, and 3.The groups show the similarities and dissimilarities of each sample related to the detrital provenance (Figure 9).
The Permian Yododeñe Formation (sample Yod21-2) resembles to Group 2 in the MDS plot (Figure 9), which is also very similar in age spectra to sample Fix21-4 from the Ixtaltepec Formation (Figure 7d,j).

Maximum depositional ages of Carboniferous-Permian succession
Biostratigraphic ages for the Carboniferous Santiago and Ixtaltepec formations were previously established (Navarro-Santillán et al. 2002;Torres Martínez and Sour Tovar 2016, 2018, 2022).The combination of these relative ages with petrographic and U-Pb geochronologic data provides evidence for contemporaneous volcanic activity, which is the main source of firstcycle zircon grains (Gehrels et al. 2011).Detrital zircon dating from the Santiago Formation reflects an MDA of 395.4 ± 2 Ma (Devonian) which is older than the biostratigraphic age (Tournasian-Visean in Navarro-Santillán et al. 2002;Castillo-Espinoza 2013).This would suggest that air-fall zircons derived from volcanic activity did not arrive in the basin during the Santiago Formation deposition.However, detrital zircons of Tournaisian age are recorded in the lower part of the Ixtaltepec Formation (youngest population with a peak at~ 359 Ma and MDA of 347.9 ± 3.6 Ma; Figure 7d).Hence, the magmatic event may have started by ~ 359 Ma (Early Mississippian), continuing during the Ixtaltepec Formation deposition.
Volcaniclastic rocks from the Ixtaltepec Formation in the Santiago-Ixtaltepec area yielded an age of 327.7 ± 1.9 Ma (Figure 8a), which is correlative, within analytical error, with the ages (330.5 ± 2 Ma and 330.2 ± 2.2 Ma) of volcaniclastic sandstone exposed in the Jaltepetongo area (Figure 8c,d).Likewise, the MDA for sandstones from the Ixtaltepec Formation is 331 ± 3.6 Ma (Figure 7e), being consistent within error with the 325.4 ± 4.5 Ma age obtained from similar rocks in the Jaltepetongo area (Figure 7f).The youngest MDAs were identified in volcaniclastic granule conglomerate (308 ± 3.5 Ma) and sandstone (319 ± 3.3 Ma) from the Jaltepetongo area (Figure 7g, h), and volcaniclastic siltstone (314.5 ± 2.1 Ma; Figure 8b) of the Santiago-Ixtaltepec area.Given the presence of similar intercalated volcaniclastic rocks and geochronological data in both areas, we interpret the rocks in the Jaltepetongo area to be a previously unknown extension of the Serpukhovian-Moscovian Ixtaltepec Formation.
The youngest detrital zircons from the Yododeñe Formation yield an MDA of 326.3 ± 4.6 Ma (Figure 7j).However, the depositional age for this unit is best constrained to the early Permian (Kungurian) because fusulinids contained in conglomerate limestone clasts are Artinskian and Kungurian (290-273 Ma;Silva-Pineda et al. 2003), and the crystallization age of a rhyodacite lava from the upper portion of the formation is 282.3 ± 1.9 Ma (Figure 8f).

Detrital provenance
A proper interpretation of detrital provenance using bulk petrography of the studied Carboniferous sandstones is hampered by the intense alteration of their original components.Mineral alteration likely resulted from hydrothermal fluid circulation induced by Permian intrusions (e.g.Haile et al. 2019), which are present throughout the entire Carboniferous successions.Despite this limitation, petrographic observations integrated with detrital zircon U-Pb geochronology allow assessing possible sediment sources.
All samples from the three formations include monocrystalline quartz with needle-shaped rutile inclusions and quartz in phaneritic and polycrystalline fragments with crystal-plastic deformation and recrystallization, which are features of medium-to high-grade (>500°C) metamorphic rocks, such as those of these amphibolite-, granulite-, and eclogite-facies rocks (Stipp et al. 2002).These features are typical of granulite-facies quartzofeldspathic rocks from the Oaxacan Complex (Solari et al. 2003;Martini et al. 2020).Detrital provenance from the Oaxacan Complex is also supported by U-Pb detrital zircon ages between ~900 and 1400 Ma (Figure 7) that are consistent with zircon ages of ~960-1350 Ma from the Oaxacan Complex (Solari et al. 2003(Solari et al. , 2014)), suggesting a predominant local source.Although the entire Carboniferous-Permian stratigraphic section shared local sediment sources, variations in detrital zircon age distribution and sand grain compositional changes suggest changes in the sediment provenance over time.

Santiago formation (Tournaisian-Visean)
In the Santiago Formation, quartz-rich and feldspar-and lithic-poor sandstone are typically associated with erosion and recycling of the craton interior and continental blocks, occurring in non-volcanic settings or passive margins (Dickinson 1985).However, an active subduction is reported in the Acatlán Complex during the Early Mississippian (Estrada-Carmona et al. 2016) and Tournaisian zircon ages (Early Mississippian) are obtained in the Ixtaltepec sandstone (Figure 7d); thus a non-volcanic settings or passive margins is unlikely.Sediment provenance is mainly from local basement sources (Group 1 in MDS plots; Figure 9).However, abundant detrital quartz, rare sedimentary or metasedimentary grains, and some quartz grains with embayment textures (absent in the recrystallized granulite of the Oaxacan Complex) are consistent with the recycling of early Palaeozoic or older metasedimentary units and igneous rocks.
Paleoproterozoic ages (~1500-1700 Ma) are rare in the Oaxacan Complex (e.g.Solari et al. 2014); and Ordovician-Silurian ages (~420-500 Ma; Figure 7a-c) are unreported in the Tiñu Formation(e.g.Gillis et al. 2005).Paleoproterozoic ages are typical of the Rondônia-San Ignacio and Río Negro-Juruena provinces of the Amazonian craton (e.g.Cordani et al. 2009).However, these ages have also been reported in several metasedimentary units, such as the Cambrian-Silurian metasedimentary Baldy unit (Martens et al. 2010; Figure 10) in the Maya Mountains and the Ediacaran Jocote unit bordering the Chiapas Massif (Weber et al. 2008;González-Guzmán et al. 2016; Figure 10).The MDS plot (Group 1) shows the Santiago Formation sandstone best fit with the Baldy and Jocote units (Figures 9 and 10), suggesting a close position of Maya Block to southern Oaxaquia during the Early-Middle Mississippian (Tournaisian-Visean).
Ordovician-Silurian ages ranging between ~420-500 Ma are present in ~2-7% of all the analysed grains in the studied samples (Figure 7).Similar ages are found in Ordovician (ca.427-466Ma) igneous and metaigneous rocks in Guatemala (Ortega-Obregón et al.Considering that ages in the range ~420-500 Ma and ~1500-1600 Ma are present in several terranes, this is difficult to explain.However, another significant detrital zircon age group at 340-420 Ma (peak at 399 Ma in sample Lpix20-4; Figure 7b) is observed in one sample of the Santiago Formation and subordinate grains are reported in the Palaeozoic cover of the Oaxacan Complex (see also Gillis et al. 2005).Similar age ranges are primarily present in the Devonian volcanosedimentary and plutonic rocks of the Maya Mountains (Rhyolite Bladen; Macal Formation and Maya Mountains granites; Figure 10), with ages in the range ~350-440 Ma and ~400-415 Ma, respectively (Steiner and Walker 1996;Martens et al. 2010;Weber et al. 2012).These ranges are also reported in the metamorphic rocks of the Sierra de Juárez Complex (Espejo-Bautista et al. 2021; Figures 2 and  10) and the Chuacús Complex of Guatemala (Maldonado 2018b; Figures 2 and 10).In the MDS plot, such age distributions (sample Lpix20-4) reflect similarities to those from the Maya Mountains, Sierra de Juaréz Complex and Chuacús Complex (Group 2; Figure 9).The detrital zircon age spectrum of the Santiago Formation (sample Lpix20-4) is comparable with that observed in the Carboniferous Macal Formation of the Maya Mountains (Figure 10), which received sediments from the aforementioned Devonian volcano-sedimentary and plutonic rocks (Martens et al. 2010), suggesting that both units could have shared the same sources during the Early Mississippian.Since the presence of Silurian-Devonian ages and few metasedimentary grains, it is likely zircons ranging from ~420-500 Ma and ~1500-1600 Ma were also derived from the adjacent Maya Block and Sierra de Juárez Complex.Hence, the Santiago sandstones received sediments mainly from local basement rock sources and recycled detritus from the underlying Tiñú Formation and adjacent peri-Gondwanan terranes.

Ixtaltepec formation (Serpukhovian-Moscovian)
Sandstone composition and spectrum of the detrital zircon suggest a sedimentary provenance distinct from the Santiago sandstone.From the lowermost portion, the composition is characterized by the increase in feldspar, volcanic and sedimentary grains, and decreased quartz (Figure 6).On the other hand, the upper portion exposed in the Jaltepetongo area is more enriched in quartz and contains fewer feldspathic grains (Figure 6).This suggests that sediments were derived from both volcanic sources and from underlying local sources.
In the lower stratigraphic levels of the Ixtaltepec Formation, one sample plots in Group 2 (sample Fix21-4; Figure 9), showing dominant Neoproterozoic-early Cambrian grains (~500-800 Ma; Figure 7d).Samples plotting in Group 2 imply the arrival of late Neoproterozoic-early Cambrian (~500-800 Ma) and Archaean-Paleoproterozoic (~1800-2800 Ma) zircons.This notable provenance shift cannot be explained by input from local sources (Gillis et al. 2005).Ages between ~840-530 Ma are known in Pan-African/Brasiliano terranes and the Goiás magmatic arc in the Amazonia craton (e.g.Cordani and Teixeira 2007), and from riftrelated igneous rocks of ~620-520 Ma age produced by rifting and opening of the Iapetus Ocean (e.g.Cawood et al. 2016;Thomas et al. 2016).In Mexico and Central America, zircons from Neoproterozoic-Cambrian igneous rocks as primary sources are uncommon.However, ages within this range have been reported in a granitic boulder within a conglomerate of the La Delicias Formation in the Coahuila Block (Figures 1a  and 2), in northern Mexico (Lopez et al. 2001); in the Yucatán peninsula basement (545 Ma, Keppie et al. 2011); and in other peri-Gondwanan terranes, such as the Suwanee terrane (Mueller et al. 2014).Detrital zircons of ~500-800 Ma age are ubiquitous, for example, in the Mississippian-Pennsylvanian Santa Rosa Formation of the Maya Block (samples SR1-3-4 in Weber et al. 2006Weber et al. , 2009;;Figure 10), in the Devonian-Carboniferous metasedimentary rocks of the Acatlán Complex (Talavera-Mendoza et al. 2005;Morales-Gámez et al. 2008;Galaz et al. 2013;Martini et al. 2020; Figure 10), and the Devonian-Carboniferous sedimentary rocks of northwestern South América (Mérida Andes and Santander Massif in sample PAA5 in Dugarte 2012;Cardona et al. 2016; Figure 10).The MDS and KDE diagrams show the similarities in zircon ages between the Ixtaltepec sandstone and the mentioned Gondwana source samples (Figures 9 and 10).Therefore, these units likely shared a Neoproterozoic-Ediacaran source related to Pan-African-Brasiliano orogeny and the opening of the Iapetus Ocean; such source was exposed at least during the Serpukhovian (Late Mississippian).Archaean and Paleoproterozoic grains could have been derived from the multi-cycle sedimentation of Amazonian basement provinces (Cordani et al. 2009).
During Pennsylvanian the ~750-530 and ~1800-2800 Ma groups disappear (Figure 7e-i), possibly due to local drainage variations and the cessation of erosion of the Neoproterozoic-Ediacaran sources at the onset of volcanism.
Volcaniclastic rocks appear interbedded with marine deposits of the Ixtaltepec Formation.The reported ages from volcaniclastic rocks at 330.5 ± 2 Ma, 330.2 ± 2.2 Ma, 327.7 ± 1.9 Ma, 314.5 ± 2.1 Ma, and 308.4 ± 3.5 Ma (Figure 7g; Figure 8a-d and Figure 10) demonstrate the first evidence for coeval Mississippian-Pennsylvanian volcanism, whose products are interbedded within the Ixtaltepec Formation.Magmatism of this age also includes granitoids of the northeastern Maya block (326 Ma; Zhao et al. 2020;Ross et al. 2022), granites from the Altos Cuchumatanes in Guatemala (317 Ma, Solari et al. 2010), the Pezuña Peperite (331-270 Ma) in the Coahuila Block (Lopez 1997), as well as the ash deposits within the Late Devonian-Middle Permian Patlanoaya Formation in the Mixteco Terrane (Vachard and Flores de Dios 2002;Ramos-Arias et al. 2008; Figure 2) and in the Permian Tuzancoa Formation (Rosales-Lagarde et al. 2005) in northern Oaxaquia.In North America, tuffs from the Ouachita mountains and Midland basin in Texas (Tian et al. 2022a; Figures 1a and  10) that best match with the volcano-sedimentary rocks from Ixtaltepec Formation (Figure 10), as well as the Sabine Terrane in Texas (Nicholas and Waddell 1989) also show Mississippian volcanism interpreted as sourced from Gondwana periphery arcs.The Ixtaltepec sandstone samples (Samples Fix21-2; Jal21-4,Yuc21-1 and SIJ20-4; Figure 10) are similar in their zircon spectrum to one sample with detritus from the East Mexico Arc (e.g.sample TT82 from Tecomate Formation in Kirsch et al. 2012;Figures 9 and 10) and samples from Group 1 (Figure 9).Thus, sediments were derived from synsedimentary volcanism mixed with detritus from the Oaxacan Complex (Groups 1 and 3; Figure 9).The youngest zircons ranging from ~300 to 370 Ma in the sandstones (peaks at 359, 341, 325, 321 Ma; Figure 7e-i) and volcaniclastic rocks (Figure 8a-d) from the Ixtaltepec Formation are likely sourced from arc magmatism developed in north-northwest Gondwana in different tectonic scenarios (e.g.Ortega-Obregón et al. 2014;Coombs et al. 2020;Tian et al. 2022a).Detrital zircon between 350 and 370 Ma has been interpreted as derived from a hypothetical Devonian-Mississippian arc that would have been removed by subduction erosion along the northwestern margin of Gondwana (e.g.Keppie et al. 2008;Kirsch et al. 2012).Considering the isotopic data of arc-related rocks from peri-Gondwana terranes (Coahuila, Maya and Mixteco;Lopez 1997;Ortega-Obregón et al. 2014;Ramírez-Fernández et al. 2021) and the Ouachita mountains and Midland basin, (Tian et al. 2022a;2022b) et al. 2005;Kirsch et al. 2012;Ortega-Obregón et al. 2014).In this context, there is an overlap between the U-Pb zircon ages of both arcs and the ages reported here in volcaniclastic (330-314 Ma) and subvolcanic rocks (282-272 Ma), and in sandstones (detrital zircon range ~370-280 Ma).Therefore, it is interpreted that the activity of both arcs is recorded in the Carboniferous-Permian peri-arc basin overlaying the Oaxacan Complex.The transition from arc activity related to the Rheic subduction to that related to paleo-Pacific subduction in the studied basin, is of uncertain timing.Zircon Hf isotope analysis would be needed to distinguish and compare the geochemical signatures of arc-related rocks.

Yododeñe formation (Artinskian-Kungurian)
In the Yododeñe Formation, a new provenance change is observed in detrital zircon data (Figure 7j) and modal composition (Figure 6) in response to palaeogeographic changes during the Permian.
The sandstone composition is characterized by gradually increasing abundances of quartz and sedimentary lithics and decreasing quantities of felspathic grains (Figure 6).The detrital zircon data is dominated by Ediacaran-Cambrian ages with a few grains of Archaean-Paleoproterozoic age (Figure 7j).Sample Yod21-2 resembles Group 2 in MDS plot (Figure 9), which is also very similar in its zircon spectra to sample Fix21-4 from the Ixtaltepec Formation and metasedimentary rocks from other peri-Gondwana terranes (Maya Block, Acatlán Complex and Merida Andes; Figure 10).The similarity in detrital zircon U-Pb age is interpreted as indicative of uplift and unroofing of the Carboniferous or older sedimentary cover of Gondwana terranes, especially those of Oaxaquia, the Mixteco Terrane, the Maya and Coahuila blocks.

Carboniferous-permian tectonic evolution
Sediments of the Carboniferous-Permian units are consistent with the provenance from the proximal basement, and older sedimentary rocks (Oaxacan Complex and Tiñu Formation), peri-Gondwanan and Gondwanan sources, and the youngest zircon ages are related to one or more magmatic arcs.The observed provenance shift over time allows us to constrain the tectonic evolution of the Carboniferous-Permian periarc basinal-strata exposed in the Santiago Ixtaltepec and Jaltepetongo areas in two time-frames: 1) a pre-collisional stage before the assembly of western Pangea, characterized by magmatic arc activity initially related to the subduction of Rheic ocean crust during the Mississippian-Pennsylvanian, and eventually, to the Paleo-pacific oceanic crust subduction under western Gondwana during the Late Pennsylvanian-Permian; and 2) a stage of continental collision and accretion between Gondwana and Laurentia during the Ouachita-Marathon-Sonora orogeny in early Permian times.
According to the new provenance results, during the pre-collisional stage in Early Mississippian time (Santiago Formation,, basins in Oaxaquia and the Maya blocks shared similar provenance.The basins were fed by reworked pre-Carboniferous igneous and metasedimentary units (mainly from the Maya Mountains, Chuacús and Sierra de Juárez complexes Figure 11a).The Early Mississippian Santiago Formation was deposited in an active margin in a back-arc position distal to the subduction zone.An active subduction scenario is plausible because it has been documented in high-pressure rocks in the Acatlán Complex during the Early Mississippian (350-340 Ma; Keppie et al. 2008).The active margin may be related to the closure of the Rheic Ocean (Nance et al. 2012;Estrada-Carmona et al. 2016).During the closure process of the Rheic Ocean, the peri-Gondwanan inter-terrane basins continued to share sediment provenance with units of the Maya block, Coahuila block, northwestern South America, and Mixteco Terrane (Figure 11b).This provenance is supported by the abundant Ediacaran-early Cambrian zircon ages (Group 2; Figure 9), whereas the closeness of Laurentia and Gondwana is supported by the faunal affinity of the Santiago and Ixtaltpec formations with the Midcontinent province of eastern and central United States and South America (Navarro-Santillán et al. 2002;Castillo-Espinoza 2013;Torres Martínez and Sour Tovar 2016).During this time, shift in provenance and input of volcanic detritus occurred as a response to palaeogeographic changes related to the subduction of the Rheic Ocean crust.Along northern and northwestern Gondwana, continental arcs were developed.Hence, sedimentation of Carboniferous units from Oaxaquia took place in a periarc setting (likely back arc-basin; Figure 11b), the activity of which may have started at ~359 Ma because of the erosion and arrival of volcanic sediment between ~359 and 308 Ma during deposition of the Ixtaltepec Formation.
Palaeogeographic models propose a clockwise rotation of Gondwana with respect to Laurentia, with the closure of the Rheic Ocean occurring by an east-west zippered oblique continental collision between both continents (e.g.Hatcher 2010), with the collision beginning in the Late Mississippian south of the Appalachian foreland and continuing until the late Permian to form the Ouachita-Marathon-Sonora orogen during the Pangea assembly (Poole et al. 2005).
During the final Pangea assembly stage, the activity of the northern Gondwana arc ended by ~286 Ma (Tian et al. 2022b).During the collision between Gondwana and Laurentia, the plate motion produced that Oaxaquia and the Mixteco terranes did not collide head-on with southern Laurentia (Nance et al. 2012).Instead, these terranes were brought to the margins of the subduction zone of the paleo-Pacific Ocean beneath Gondwana in the late Carboniferous (Keppie et al. 2008), forming the western Pangea arc (East Mexico Arc; Kirsch et al. 2012).In the Carboniferous-Permian succession, the East Mexico Arc activity is evidenced by the presence of subvolcanic rocks and lavas of age similar to the plutonic rocks of the Oaxacan and Acatlán complexes (Figure 11c).
After the Pangea assembly, the reorganization of plates produced the accretion between the Acatlán Complex and Oaxaquia terranes in the early-middle Permian along the Caltepec fault (Elías-Herrera and Ortega-Gutiérrez 2002), forming a transpressive belt (Ortega-Gutiérrez et al. 2018).At this time, the marine environment ended in southern Oaxaquia, and carbonate sediments were suppressed during the deposition of clastic sediments of the Yododeñe Formation in continental or deltaic environments.The abundance of sedimentary lithics and detrital zircons similar to Group 2 in the MDS diagram (Figures 9) and KDE plots (Figure 10) suggest the accretion, uplift and erosion of Carboniferous successions in southern México (Maya Block, Oaxaquia, Coahuila, and Mixteco terranes) by Cisuralian time, coinciding with the Ouachita-Marathon-Sonora orogeny and the accretion of the Oaxacan and Acatlán complexes (Elías-Herrera and Ortega-Gutiérrez 2002; Poole et al. 2005;Soreghan and Soreghan 2013;Soto-Kerans et al. 2020;Figure 11c,d) Along the Ouachita-Marathon-Sonora orogenic belt, the oblique collision produced a strike-slip fault, fold and thrust belt, and related basins along the northern margin of the Ouachita-Marathon suture (Figure 11d; Poole et al. 2005;Hatcher 2010).In North America, sediments in the foreland basins (Delaware and Fort Worth basins) were interpreted as being derived from Gondwanan sources (e.g.Soreghan and Soreghan 2013;Alsalem et al. 2018;Thomas et al. 2019;Gao et al. 2020;Liu and Stockli 2020;Soto-Kerans et al. 2020).These basins contain detrital signatures very similar to the Yododeñe Formation sandstones; hence, both could have shared similar sources.

Conclusions
Geochronological and petrological data from Carboniferous-Permian successions overlying the Oaxacan Complex, southern Mexico, reveal provenance changes through time associated with the tectonic evolution of the Pangea assembly.
• The Mississippian Santiago Formation would have formed along the active margin in the absence of arc-activity, recording local recycling of proximal sources such as the Oaxacan Complex and the Cambrian-Ordovician Tiñú Formation and older Neoproterozoic -early Palaeozoic metasedimentary units of adjacent peri-Gondwanan terranes (e.g.Maya block, Chuacús Complex, and Sierra de Juárez Complex).

Figure 3 .
Figure 3. Geologic maps and simplified stratigraphic columns of Palaeozoic sedimentary rocks exposed near Asunción Nochixtlán, Oaxaca, southern Mexico.a) Geologic map of the Santiago Ixtaltepec area (modified from Centeno-Garcia and Keppie 1999).b) Simplified stratigraphic columns of the Santiago Ixtaltepec area (S1 and S2 represent stratigraphic sections).c) Geologic map of the Jaltepetongo area (compiled from 1:50 000 Asunción Nochixtlán, Oaxaca charts E14-D36 of Servicio Geológico Mexicano and fieldwork in this study).d) Simplified stratigraphic columns of the Jaltepetongo area (S1a, S2a, and S3a represent stratigraphic sections).Maps and columns show the locations of samples analysed in this work (see Figure 1b for the location of each studied area).

Figure 4 .
Figure 4. Photographs of the Ixtaltepec and Yododeñe formations outcrops.a) L-Limestone, Vs-Volcaniclastic siltstone showing parallel-lamination and sharp contacts, Si-siltstone, and S-sandstone from the Ixtaltepec Formation in Las Pulgas section in Santiago Ixtaltepec area.b) Load and flame structures (black arrow) and upper-plane lamination (black parallel lines) from the Ixtaltepec Formation in S1a section.c) Rhyo-dacitic hypabyssal sills (RD) overlain by fossiliferous limestone (L) in the S1a in the Jaltepetongo area.d) Sandstone, siltstone, and shale from the Yododeñe Formation overlain by rhyodacitic lavas.

Figure 6 .
Figure 6.Detrital modes for the Carboniferous-Permian sandstone exposed in the Santiago Ixtaltepec and Jaltepetongo areas.a) QFL plot showing the classification of studied sandstones (nomenclature is after Garzanti 2016), b) QmKP plot showing the proportion of monocrystalline quartz (Qm), K-feldspar (K), and plagioclase (P), c) LmLvLs plot displaying the abundance of metamorphic (Lm), volcanic (Lv) and sedimentary (Ls) lithic grains.The schematic stratigraphic position of the samples is shown.

Figure 7 .
Figure 7. Concordia diagrams for U-Pb detrital zircon ages of Carboniferous-Permian successions overlying Oaxacan Complex.Insetsshow ages younger than 500 Ma.Plots were constructed using 206 Pb/ 238 U ages for zircon grains younger than 1.4 Ga, and 207 Pb/ 206 Pb ages for zircon grains older than 1.4 Ga.Error ellipses are at the 2σ level.Kernel Density Estimator (KDE) diagrams from Isoplot R software package programme of Vermeesch (2018) using 50 Ma bandwidth and histogram with 100 Ma bin width.YGC2σ = weighted mean age of the youngest cluster of three or more grain ages (n ≥ 3) overlapping in age at 2σ, representing the maximum depositional age(Dickinson and Gehrels 2009).Empty ellipses are analysed with 10% normal and 3% reverse discordance, which were discarded from statistical analysis.

Figure 10 .
Figure 10.Kernel Density Estimator (KDE) diagrams (Vermeesch 2018) and histograms showing the comparison of zircon age distributions of representative samples of Carboniferous sedimentary and volcano-sedimentary rocks here reported (density curve in green) from peri-Gondwana terranes (density curve in purple).References are shown in the figure.
suggest the existence of two different arcs settings: 1) North Gondwana arc, formed by southward subduction of the Rheic oceanic plate beneath Gondwana realm before the Pangea amalgamation at ~350-317 Ma; and 2) Western Pangea arc (East Mexico Arc) developed during eastward subduction of the proto-Pacific oceanic plate under the northwestern margin of Gondwana at ~311 -255 Ma following Pangea assembly (Rosales-Lagarde

Figure 11 .
Figure 11.Tectonic evolution of interaction between peri-Gondwana, Gondwana and the Laurentia margin during the Carboniferous-Permian.a) Deposition of the Tournaisian-Visean Santiago Formation during the initial stage of a magmatic arc on the northern margin of Gondwana.b) During the Serpukhovian-Moscovian, the Ixtaltepec Formation records the activity of a proximal magmatic arc related to subduction of the Rheic Ocean along the northern margin of Gondwana.Basin shared sediment provenance with units from the Maya and Coahuila blocks, and northWestern South America.c) After Rheic ocean closure, Oaxaquia and Acatlán Complex record magmatism active during the subduction of Paleo-Pacific beneath the western Pangea during the Late Pennsylvanian-early Permian.d) Early Permian Yododeñe Formation records exhumation and recycling of Carboniferous strata of peri-Gondwana sources during final stages of Pangea assembly.Acatlán Complex and Oaxaquia are accreted.Model based on Weber et al. (20071999), Kirsch et al. (2012); Ortega-Obregón et al. (2014), Lawton et al. (2021) and Tian et al. (2022a and 2022b).
• Volcaniclastic sandstone from the Late Mississippian-Middle Pennsylvanian Ixtaltepec Formation records the Mississippian-Pennsylvanian volcanic activity (~330-308 Ma) in the Oaxacan Complex and southern México, documented for the first time in this work.This study also reports a new Carboniferous marine volcanosedimentary unit in the Jaltepetongo area, correlative with the Ixtaltepec Formation in the Santiago Ixtaltepec area in northern Oaxaca state.• The presence of volcanogenic sedimentary and igneous rocks is interpreted as input of volcanic material within the peri-arc basin fed by Carboniferous-Permian arcs.Sandstones petrography and, mostly, zircon U-Pb dates from volcanosedimentary and sandstone units, suggest that the arc formed during the southward subduction of the Rheic ocean beneath Gondwana during 360-308 Ma (Early Mississippian-Middle Pennsylvanian).Permian sub-volcanic rocks intruding the Carboniferous unit are related to a second arc developed in the Acatlán and Oaxacan complexes after Pangea assembly due to the eastward subduction of the paleo-Pacific Ocean under the western margin of Pangea.• Sandstones from the Ixtaltepec Formation show abundant Ediacaran-Cambrian zircon ages.The input of ~750-530 Ma zircons occurred during Mississippian time, similar to what is reported in the Maya Block, Acatlán Complex, Coahuila block, and Carboniferous rocks from northwestern South America.• Sandstones from the early Permian Yododeñe Formation indicate a significant provenance change, with lithic-enriched sediments, demonstrating erosion of Carboniferous or older sedimentary cover.The sedimentary cover was exhumed during the diachronous collision between Gondwana and Laurentia and the resulting Ouachita-Marathon-Sonora orogeny and by the accretion of the Acatlán Complex and Oaxaquia in early-middle Permian.