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In their paper: U–Pb geochronology of intrusive rocks of northwestern Mesa Central province and Sector Transversal of Sierra Madre Oriental, Mexico: Time and space distribution of inland Cretaceous-Paleogene magmatism during the Mexican orogeny, Díaz-Bravo et al. (2022) present a database of geochronological ages reported in literature and seven generated by themselves, with which they adapt a model of flat-slab subduction to explain the geographical distribution of the Cretaceous-Paleogene magmatism in north-central Mexico. In our opinion, the paper contains limited bibliographic documentation, since it omits previously published zircon U–Pb ages, whose relationship with the Mexican orogeny has been discussed in several previously published papers. Furthermore, an important approach on the distribution of plutons is that the effects of contractional deformation during pluton emplacement and younger extensional tectonics in the studied area were not evaluated. We propose that the syntectonic relationships with the Mexican Orogeny for some of the plutons imply that the magmas were emplaced in rocks undergoing shortening and eastward-NE translation during the development of the Mexican fold and thrust belt. Therefore, they are not in their original position and must be carefully studied to establish the magmatic model presented in this work. • The Cretaceous plutons in the Mesa Central and Sector Transversal of the Sierra Madre Oriental are syntectonic to the development of the Mexican Fold and Thrust Belt. • The Cretaceous syntectonic plutons are allochthonous, so they do not represent a fixed position to model the subduction angle of the Farallon plate. • Pico de Teyra and El Peñuelo plutons show evidence of mylonitic recrystallization, S-C structures, and cleavage, congruent with northeastward tectonic transport of the Mexican Fold and Thrust Belt. [ABSTRACT FROM AUTHOR]

The Mosasauridae underwent a major radiation early in the Late Cretaceous, with the subfamilies Plioplatecarpini and Tylosaurini appearing in the Turonian. Here we report an almost complete mosasaur skull assigned to the plioplatecarpine genus Yaguarasaurus. The specimen was discovered southwest of Vallecillo in the northeastern Mexico state of Nuevo Leon, about 80 km north of Monterrey, in a laminated limestone layer of the upper member of the Agua Nueva Formation (Upper Turonian - ?Lower Coniacian). The specimen is referred to as a new species, Y. regiomontanus. This is the first report of Yaguarasaurus from Mexico and the most complete of the Americas. At roughly 5 m in length, it is one of the earliest large mosasaurids. Along with Yaguarasaurus columbianus , Russellosaurus coheni , and an unnamed plioplatecarpine from Texas, it documents the rapid diversification and expansion of plioplatecarpines in the marine realm in the Turonian. • The Highlight of the paper is that is a new species of mosasaurus described for Mexico. [ABSTRACT FROM AUTHOR]

This paper reports for the first time the presence of Famennian conodonts from a shallow marine succession exposed in the Cerro La Cueva, central Sonora, northwestern Mexico. The conodont fauna includes Bispathodus aculeatus aculeatus (Branson and Mehl) , Bispathodus stabilis (Branson and Mehl), ' Icriodus ' darbyensis Klapper, Polygnathus extralobatus Schäfer, Polygnathus semicostatus Branson and Mehl, Polygnathus cf. inornatus E.R. Branson, and Polygnathus aff. purus Voges, which are typical species from the late Famennian. The most biostratigraphically important species of this assemblage are " Icriodus " darbyensis and Polygnathus extralobatus , which indicate an expansa Zones age interval. This finding allows identification of Devonian rocks in the area of San Pedro de la Cueva located north of the El Novillo dam, where only Ordovician and Mississippian fossils have been previously documented. The identified conodont genera preliminarily indicate an outer marine shelf paleoenvironment. Studied strata are correlated with Devonian lithostratigraphic units previously defined in other areas of Sonora, especially in the Sierra Agua Verde, located approximately 15 km west of the Cerro La Cueva section. • First Late Devonian conodonts from the El Novillo reservoir area. • First Upper Devonian rocks reported in the study area. • Cerro La Cueva is the northeasternmost outcrop of Upper Devonian continental-shelf facies in Sonora. • Cerro La Cueva strata correlate with Upper Devonian rocks previously reported in the Sierra Agua Verde. [ABSTRACT FROM AUTHOR]

Abstract The present paper address the occurrence of Venericardia shell concentrations distributed over hundreds of meters along terrigenous horizons as a typical sedimentary facies of the Wilcox Formation in the Burgos Basin. These extensive deposits overlie Paleogene sandstones so common around the municipality of China, Nuevo León, that they are almost overlooked. This report documents for the first time the ichnological assemblage and shell accumulations of the Paleogene in the Burgos Basin. Ophiomorpha cf. nodosa and Ophiomorpha isp. from Skolithos ichnofacies are the main identified trace fossils; the probable paleoenvironment is a near-shore shallow sea under high-energy conditions related to coastal bars. The analyzed taphonomic features suggest that Venericardia shell concentrated or accumulated as bioevents resulting from intermitent tempestites in the proximal zone. These accumulations are composed of the species Venericardia (Venicor) zapatai organized as regular and linear shell arrangements contained within a frail sedimentary matrix from which they are easily-extracted. Highlights • The Burgos basin records Thanetian-Ypresian transgressive and regressive sedimentary cycles with abundant shell concentrations. • Venericardia (Venericor) zapatai accumulated through sporadic shoreface environments. • The ichnogenus Ophiomorpha and its sedimentological association with Venericardia sp. shells is preserved in the Burgos basin. • Large benthic foraminifera (Discocyclina sp.) are abundantly preserved inside Venericardia shells. [ABSTRACT FROM AUTHOR]

The geomorphometric classifications of three groups of volcanoes situated in the Andes Cordillera, Central America, and Mexico are performed and compared. Input data are eight local topographic gradients (i.e. elevation differences) obtained by processing each volcano raster ASTER-GDEM data. The pixels of each volcano DEM have been classified into 17 classes through a K- means clustering procedure following principal component analysis of the gradients. The spatial distribution of the classes, representing homogeneous terrain units, is shown on thematic colour maps, where colours are assigned according to mean slope and aspect class values. The interpretation of the geomorphometric classification of the volcanoes is based on the statistics of both gradients and morphometric parameters (slope, aspect and elevation). The latter were used for a comparison of the volcanoes, performed through classes’ slope/aspect scatterplots and multidimensional methods. In this paper, we apply the mentioned methodology on 21 volcanoes, randomly chosen from Mexico to Patagonia, to show how it may contribute to detect geomorphological similarities and differences among them. As such, both its descriptive and graphical abilities may be a useful complement to future volcanological studies. [ABSTRACT FROM AUTHOR]

The state of Oaxaca is one of the most geologically complex and diverse in Mexico. It comprises five tectonostratigraphic terranes of contrasting nature that form a sort of tectonic collage where several magmatic pulses were developed. The different lithological assemblages of Oaxaca favored the generation of a variety of ore deposit types, some of which have been a prime source of several commodities for centuries. This paper addresses the time-space relationship between ore deposits and tectono-magmatic events, based upon the available descriptions and radiometric ages. Most Meso-to Neoproterozoic ore deposits of Mexico occur in this region, and were formed during the regional granulite-facies metamorphic stage(s) recorded in the Oaxacan Complex. Such deposits are rare element-bearing pegmatites, nelsonites (ilmenite-apatite rich rocks), Ti-rich anorthosites, and pegmatites. The Oaxacan Complex also hosts a number of orogenic gold lodes that were likely formed in more than a single metamorphic episode and still require additional research to clarify their age and geological affiliation. The onset of arc-related magmatism in the Late Carboniferous-Permian is recorded by the intrusion of the calc-alkaline Zaniza, Cuanana and Honduras batholiths, along with several minor deformed and undeformed bodies enclosed in the Oaxacan Complex. Little is known about the metallogeny associated with such magmatism. Although supra-subduction magmatism re-initiated in the Jurassic and is probably responsible for the San Juan Mazatlán Cu porphyry, most of the metallogeny of Oaxaca is tightly linked to the Sierra Madre del Sur (SMS) igneous province, which began in Jalisco by the Late Cretaceous and migrated to the SE until it reached the Isthmus of Tehuantepec by the Middle Miocene. In Oaxaca, the Oligocene-Miocene coastal belt of granitic-granodioritic intrusions accounts for some IOCG deposits, especially in its easternmost portion, which then continues to the Coastal Chiapanecan Neogene batholithic belt. In W-NW Oaxaca, the intracontinental igneous province of the SMS marked the beginning of Cenozoic magmatism and is represented by thick volcanic-hypabyssal successions along with minor intrusions, with which copious magmatic-hydrothermal deposits are associated. Early Eocene and mid-Oligocene volcanism is restricted to the western half of the state, where basic-to intermediate-composition effusive products occur in the Mixteca and western Oaxaca tectonostratigraphic terranes. During this time span, many low-to intermediate-sulfidation epithermal, Fe-rich (IOCG) and polymetallic skarn deposits were produced. However, the "boom" in magmatic-hydrothermal mineralizations occurred during the terminal pulses of the SMS volcanism (Miocene), which comprise profuse intermediate volcanic rocks capped by the outburst of silicic magmatism. The early-to mid-Miocene event constitutes the most prominent in terms of metal endowment and diversity of ore deposit types, accounting for about 250 deposits and occurrences in the central and near-eastern portions of the state, which are ascribed to low-to intermediate-sulfidation epithermal, sulfide skarns, IOCG "clan" and Cu(–Mo) porphyry types. Among these, epithermal deposits are, by far, the most abundant type. Recent Ti-rich beach deposits and Au alluvial placers are present in southern and easternmost Oaxaca, respectively. In addition, supergene enrichment zones and uneconomic laterites occurrences are found in some localities. Oaxacan ore deposits can be grouped into five major metallogenic epochs: 1) Meso-Neoproterozoic REE-Th-U-Ti deposits and, possibly, orogenic gold lodes during the Olmecan-Zapotecan events (assembly of Rodinia); 2) feasible late Carboniferous-Permian (?) orogenic gold deposits; 3) early Eocene Ag–Au–Pb–Zn–Fe deposits during the onset of the SMS volcanic activity; 4) mid-Oligocene Ag–Pb–Zn–Sb–Hg–Fe(-Au) deposits during effusive-dominated pulses of the SMS volcanism; and 5) early-to mid-Miocene Au–Ag–Pb–Zn–Cu–Fe(-Mo-Sb) deposits during the termination of the SMS magmatism. The existence of a wealth of ore deposits with varying features underlines the economic potential of metallogenetic provinces and epochs in Oaxaca and exalts the necessity to expand the knowledge regarding the tectonic-magmatic-metallogenic evolution of the state. • The state of Oaxaca records a complex geological and metallogenic history. • Ore deposits in Oaxaca are magmatic-hydrothermal, orthomagmatic, metamorphic and sedimentary. • Oaxacan ore deposits comprise different typologies with contrasting natures and ages. • The boom in deposit formation is coeval with the Sierra Madre del Sur magmatism. • Basement-related deposits are mostly linked to the evolution of the Oaxacan Complex. [ABSTRACT FROM AUTHOR]

This paper dates the El Chango Lagerstätte (Chiapas, SE Mexico), known for its exceptionally well-preserved marine fishes, plant remains, crustaceans, insects and mollusks, based on ammonite biostratigraphy. The age of the El Chango fauna is imprecisely assigned to either the late Albian or Cenomanian. We document here an ammonite assemblage comprising Graysonites and ? Metengonoceras . Graysonites, which gives a lowermost early Cenomanian age, Cintalapa Formation pro parte . We noticed that the terminology of lithostratigraphic units in the studied area is confusing and varies considerably depending on the author, therefore proposing the use of Cintalapa Formation for the El Chango section and the Sierra Madre as a group that includes it. [ABSTRACT FROM AUTHOR]

Well-adapted to high-standard science at the time, Carl Burckhardt made a relevant contribution to stratigraphy in Mexico, providing the guidelines for subsequent research. A revision of his pervasive influence focuses in the interpretation of the ammonite genus Kossmatia Uhlig, with reference to Burckhardt's interpretations between 1906 and 1930, and to those made by subsequent authors. The historical revision of interpretations made at the species- and genus-level reveals a rather "blind follow-up" of Burckhardt's biostratigraphy during the majority of the 20th century. The resulting slowing-down in knowledge was forced by the common discontinuity in ammonite records, unfavorable preservation, relative rarity of ammonite-rich horizons, endemism, and especially by sampling procedures and unnoticed clues in Burckhardt's papers that would have served as guidelines to drive a more appropriate progress. Only since the nineties of 20 th century, interpretations of Mexican Kossmatia benefited from application of horizon-biostratigraphy, and complementary information derived from calpionellids. Aside from mere morphologic grounds, precise biostratigraphy and the favored paleobiogeographic model dynamics support the formal proposal of two new taxa of genus level to replace the use of the taxon-name Kossmatia for Mexican ammonites. The new taxa Burckhardtieia and Aguilerites are endemic and inconclusively known because of selective preservation favoring phragmocones against body-chambers. The new taxonomic proposal helps to identify a local fauna that distributed across the southern north-American plate during middle-to-late Early Tithonian (two-fold division) to Lower and early-Middle Berriasian times, while its origin can only be tentatively interpreted at present. • Carl Burckhardt (1912) first used Kossmatia for Latest Jurassic ammonites in Mexico. • Gaps in ammonite records, preservation, and sampling, hampered fine biostratigraphy. • Horizon-biostratigraphy as the tipping-point for revisions in the past nineties. • Updated revision of Kossmatia literature precludes its application in Mexico. • Bidding two new Mexican taxa fits revisions of Kossmatia literature, recent data, and updated interpretations. [ABSTRACT FROM AUTHOR]