Paleontological Sites of the Middle Devonian of Floresta, Boyacá

Description

5°51'35.36"N; 72°55'7.78"O (Floresta Municipality)

5°52'13.21"N;  72°56'57.22"O (Quebrada Monticelo)

5°48'41.55"N; 72°53'50.96"W (Quebrada Las Pilas)

5°49'41.29"N; 72°55'35.67"W (Potrero Rincón)

The Paleontological Sites of the Middle Devonian of Floresta, Boyacá comprise four distinct localities with a primary focus on paleontological exploration. These sites have garnered significant attention due to the discovery of well-preserved specimens of various marine invertebrates, including brachiopods, trilobites, bivalves, bryozoans, cephalopods, corals, crinoids, gastropods, and crustaceans from the Middle Devonian in Colombia.

Situated in the Altiplano Cundiboyacense within the Tundama province of the department of Boyacá, Colombia, specifically within the municipality of Floresta, these four localities offer a unique window into the ancient marine ecosystems of the Middle Devonian. The diversity of fossils found in this region provides valuable insights for researchers and paleontologists studying the evolution and dynamics of marine life during this geological period. The significance of these paleontological localities lies in their ability to contribute to our understanding of past environments, aiding in the reconstruction of the ecosystems that thrived in the Middle Devonian in Colombia.

The fossils found in this region are situated within the geological unit known as the Floresta Formation (Mojica & Villarroel, 1984^[1], Ulloa et al., 2003^[2]). The dating of this formation to the Middle Devonian has been established through taxonomic analyses, more precisely, the Formation has been dated to the late Emsian through the Givetian period based on further taxonomic studies of brachiopods and trilobites (Caster, 1939^[3]; Morzadec et al., 2015^[4]).

The intrinsic characteristics that distinguish this paleontological site encompass both its remarkable fossiliferous abundance and the exceptional degree of preservation exhibited by a multitude of associated fossil remains. This invaluable paleontological resource has facilitated the documentation of numerous specimens belonging to a diverse array of marine invertebrates, including brachiopods, trilobites, bivalves, bryozoans, cephalopods, corals, crinoids, gastropods, and crustaceans from the Middle Devonian period (Caster, 1939).

The rocks of the Floresta Formation are exposed within the Floresta Massif, situated in the Eastern Cordillera of Boyacá, Colombia. This geological structure is geographically confined, bordered to the west by the Boyacá Fault and to the east by the Soápaga Fault. These faults, exhibiting a reverse type and oriented in a NNE-SSW direction, played a crucial role in controlling the sedimentation and preservation of Paleozoic and Triassic-Jurassic units within the region (Kammer, 1996^[5]; Mojica & Villarroel, 1984; Ulloa et al., 2003).

The Floresta Massif itself is characterized by a central crystalline core, comprising rocks subjected to regional metamorphism and Paleozoic-age granitic intrusions (Botero, 1946^[6]; Cediel, 1976^[7]). Overlying this core is the Devonian sedimentary succession, encompassing the Tibet Formation, Floresta Formation, and Cuche Formation. The Tibet Formation is identified by intercalations of granodecrescent sequences, featuring medium-grained sandstones and mudstone levels indicative of a Lower Devonian meandering river depositional environment. The Floresta Formation, covering the Early Devonian to Middle Devonian period (Emsian-Givetian), is succeeded by the Cuche Formation, characterized by mudstones and fine-grained sandstones representative of coastal depositional environments and extending from the Upper Devonian to the Carboniferous. The geological succession within the Floresta Massif concludes with the Cuche Formation, which discordantly underlies the Jurassic Girón Formation (Botero, 1946; Cediel, 1976).

The Floresta Formation, situated within the Floresta Massif on Plancha 172 Paz de Río, exhibits a substantial thickness, reaching approximately 700 meters. It covers an expansive area of about 60 km² (Ulloa et al., 2003). The Floresta Formation is characterized by three distinct segments. The basal segment consists of medium-grained sandstones, followed by an intermediate segment featuring intercalations of fossiliferous gray mudstones, micaceous siltstones, and claystones. The upper segment is composed of black fissile mudstones (Mojica & Villarroel, 1984). These lithological characteristics are indicative of marine depositional environments, with distinct marine cycles marked by representative maximum flooding zones identified through the presence of brachiopod ortids. Additionally, the formation represents coastal environments, portraying a siliciclastic transgressive platform with storm effects, this variation reflects a transition from offshore to lower shoreface, contributing to the overall understanding of the geological and paleoenvironmental context of the region (Pastor, 2020^[8]).

^[1] Mojica, J., & Villarroel, C. (1984). Contribution to the knowledge of the Paleozoic units of the Floresta area (Eastern Colombian Cordillera; Department of Boyacá) and especially to that of the Cuche Formation. Colombian Geology, 13, 55-79.

^[2] Ulloa, C., Rodríguez, E., & Rodríguez, G. (2003). Geology of the 172 Paz de Río plate. Ingeominas, Bogotá.

^[3] Caster, K. (1939). A Devonian Fauna from Colombia. Bulletin of American Paleontology: Vol. XXIV (Número 83, pp. 107-219).

^[4] Morzadec, P., Mergl, M., Villarroel, C., Janvier, P., y Racheboeuf, P. R. (2015). Trilobites and inarticulate brachiopods from the devonian floresta formation of Colombia: A review. Bulletin of Geosciences, 90(2), 331–358. https://doi.org/10.3140/bull.geosci.1515

^[5] Kammer, A. (1996). Structures and deformation of the eastern edge of the Floresta Massif. Colombian Geology (Vol. 21).

^[6] Botero, G. (1946). Geological survey of the area of Belén, Cerinza, Corrales, Floresta, Nobsa and Santa Rosa de Viterbo in the Department of Boyacá. National Geological Service.

^[7] Cediel, F. (1976). Geology of the Floresta Massif. I Colombian Congress of Geology Proceedings, 17-29.

^[8] Pastor, A. F. (2020). Sedimentology and characterization as hydrocarbon source rock of the Floresta Formation, Floresta Massif, Colombia. National University of Colombia.

Justification of Outstanding Universal Value

The Paleontological Sites of the Middle Devonian of Floresta, Boyacá, distinguish themselves from other Devonian rock exposures worldwide by encompassing not just a single location but a remarkable cluster of four distinct localities. This collection spans a considerable stratigraphic range, extending from the Emsian to the Givetian stages, thereby covering the entire Middle Devonian stratigraphic sequence.

What sets these localities apart is their comprehensive geological representation. Beginning at the base and overlying rocks of the Lower Devonian Tibet Formation, the sites progress through the Middle Devonian sequence and conclude at the top, underlain by rocks of the Upper Devonian Cuche Formation. This broad coverage provides a unique opportunity for researchers and geologists to study the entire spectrum of Middle Devonian geological and paleontological features within a specific region, setting the Paleontological Localities of the Middle Devonian of Floresta apart as an exceptional and comprehensive resource in the global context of Devonian rock exposures.

Also, the Paleontological Sites of the Middle Devonian of Floresta, Boyacá, serves as a prominent reference for documenting faunal diversity. It makes significant contributions to the fields of taxonomy, phylogeny, biostratigraphy, and paleogeography within the Middle Devonian (Moreno-Sánchez et al., 2020^[1]), not only on a national scale in Colombia but also internationally. This distinction is attributed to the reported occurrences, the definition of new species, localities and type horizons. These aspects collectively establish that these sites are a crucial biostratigraphic and paleobiogeographic control point for the south american region.

The fossil record of marine invertebrates at these sites are particularly extensive, encompassing reports on more than 120 genera and 70 species (Caster, 1939; Mc Nair, 1940^[2]; Royo y Gómez, 1941^[3]; Herrera, 1951^[4]; Morzadec et al., 2015; Gómez et al., 2019^[5]; Patarroyo et al., 2019^[6]; Beltrán-Rondón et al., 2020^[7]; Moreno-Sánchez et al., 2020). Notably, it includes the first documentation of three subfamilies, two families, 15 genera, and 54 species. Furthermore, these sites have yielded the identification of 54 holotypes, and 37 paratypes.

Within this notable paleontological deposit, two distinct localities and their corresponding type horizons serve to temporally define the rock formations of the Floresta Formation. The first locality, situated in Quebrada Monticelo (Monticelo Creek), stands as the type locality for the trilobite species Colombianaspis carvalhoae (Morzadec et al., 2015), concurrently establishing a type horizon within the late Emsian for the lower segment of the Floresta Formation (Morzadec et al., 2015).

Moreover, another locality, situated along Quebrada Las Pilas (Las Pilas Creek), boasts the documentation of a novel species—an inarticulate brachiopod named Schizobolus pilasiensis (Morzadec et al., 2015). This locality not only serves as the holotype and paratype site for this species but also delineates a type horizon within the Givetian for the upper segment of the Floresta Formation (Morzadec et al., 2015). The establishment of these specific localities and type horizons significantly contributes to our nuanced understanding of the temporal framework and geological evolution encapsulated within the Floresta Formation.

Certainly, one of the most distinctive and emblematic features of these sites are situated in the locality of Quebrada Las Pilas, Potreritos Village. Here, a prominent outcrop reveals a succession of layers that, when traversed along their course, showcase fully preserved fossils of marine invertebrates. The strategic stratigraphic positioning of these layers ensures that the fossils are not only completely exposed but also boast a remarkable degree of preservation and abundance. This locality is also particular because the entire sequence of the Floresta Formation is exposed from its base to the top. This unique geological characteristic enhances the significance of Quebrada Las Pilas as a key site within the deposit, allowing for an unparalleled glimpse into the rich marine invertebrate fauna of the region.

The region encompassing the localities along the road connecting the towns of Santa Rosa de Viterbo, Floresta, and Corrales, as well as their surroundings, has been a focal point of study since 1939 and continues to be of significant interest. This area features a series of outcrops that have yielded pivotal insights into the marine invertebrate fauna of the Floresta Formation. Notably, comprehensive taxonomic reports conducted from 1939 to the present have documented three subfamilies, two families, 14 genera, and 55 species, including 52 holotypes and 36 paratypes. This rich diversity predominantly comprises brachiopods and bryozoans (Caster, 1939; Mc Nair, 1940).

Furthermore, in the locality of Potrero Rincón, notable findings include a report of brachiopods belonging to Composita sp. This discovery not only contributes to our understanding of the fossiliferous nature of the area but also establishes a temporal horizon within the Frasnian for the uppermost segment of the Floresta Formation at this specific point (Moreno-Sánchez et al., 2020).

Not to mention, the meticulous taxonomic study conducted in these geological sites has positioned them as significant references, both on a national and international scale. Nationally, these sites stand out as unique locations where new species have been formally reported for the Middle Devonian period in Colombia. This distinction underscores their pivotal role in advancing the understanding of the country's paleontological landscape.

Internationally, these sites contribute valuable insights to the broader field by serving as inputs for the reconstruction of Middle Devonian paleogeography. The faunal affinities observed in these sites, particularly with the faunal province of Eastern America, make them integral to the global context. This international relevance emphasizes the broader impact of these geological sites and their role in enhancing our understanding of the Middle Devonian on a global scale.

Finally in terms of the state of preservation of the marine invertebrate fossils, the majority exhibit an outstanding level of preservation. Notably, complete trilobite exoskeletons, brachiopod and bivalve shells preserved from their original material, and instances where the rock matrix retains the calcareous cements are frequently encountered. The fossils include organisms in life position, fragments of bryozoans and crinoids, as well as well-preserved sedimentary structures. Additionally, various associated stratigraphic elements further enhance the scientific significance of these fossils, providing a comprehensive view of the paleontological landscape within the Floresta Formation.

The fauna that inhabited northern South America around 387 million years ago offers a unique glimpse into the early stages of life, showcasing an astonishing diversity and abundance of invertebrate organisms. This ancient ecosystem not only provides insight into the evolutionary processes at play during that era but also highlights the influence of specific environmental conditions shaped by the tectonic configuration of the time. The fauna's development is intricately tied to the distinct conditions present in the Colombian territory during the Devonian period.

This historical information holds significant value in a contemporary context, particularly as Floresta stands out as one of the most diverse and well-preserved analogues of this ancient ecosystem. Its excellent preservation allows for a comprehensive understanding of the sectoral diversification of the Devonian fauna, contributing valuable insights to our broader comprehension of evolutionary patterns.

The extraordinary richness of the Floresta fauna stands out prominently, particularly due to its diverse fossil groups. Notably, the representation of various marine invertebrates allows for the delineation of specific Ages/Stages within the Devonian period. The Emsian Age/Stage, dating back approximately 393 million years, the Givetian Age/Stage, spanning over 387 million years ago, and the final segment of the Floresta Formation aligning with the Frasnian Age/Stage at around 382 million years ago, collectively form a comprehensive stratigraphic and paleontological record. This record encapsulates all the Middle Devonian Ages/Stages for northern South America.

What further accentuates the uniqueness of the Floresta Formation is the presence of species exclusive to this region, found nowhere else in the world. This not only underscores the distinctiveness of the ecosystem but also contributes significantly to our understanding of evolutionary patterns and biogeography.

Furthermore, the scientific tradition associated with Floresta has roots dating back to 1939, establishing it as a cornerstone reference site for the acquisition of knowledge and presenting invaluable opportunities for ongoing research endeavors.

^[1] Moreno-Sánchez, M., Gómez-Cruz, A., y Buitrago-Hincapié, J. (2020). Paleozoic of Colombian Andes: New Paleontological Data and Regional Stratigraphic Review. En J. Gómez y D. Mateus–Zabala (Eds.), The Geology of Colombia (p. 37). https://doi.org/10.32685/pub.esp.35.2019.09

^[2] Mc Nair, A. H. (1940). Devonian Bryozoa from Colombia. Bulletins of American Paleontology Vol. 25. (pp. 153–198).

^[3] Royo y Gómez, J. (1941). Devonian fossils from Floresta (Department of Boyacá). Ministry of Mines and Petroleum. Number 95-41.

^[4] Herrera, E. (1951). Study on some Devonian and Cretaceous fossils from the department of Boyacá. Servicio Geológico Nacional: Vol. Report No. 788.

^[5] Gómez, A. d. J., Moreno-Sánchez, M., Lemus Restrepo, A., Vivas, D., Benjumea, S., Martínez, L. F., & Alzate, M. (2019). Favosites Sp, Corales Biohermales De La Formación Floresta. XVII Colombian Geology Congress Proceedings, 880.

^[6] Patarroyo, P., Obregón, L., & Pastor, A. (2019). CEPHALOPODS FROM THE PALEOZOIC OF COLOMBIA. XVII Colombian Congress of Geology Proceedings, 869-870.

^[7] Beltrán-Rondón, J, Reyes-Abril, J., and Tchegliakova, N. (2020). Preliminary morphotaxonomy of bivalves from the Floresta Formation, Middle Devonian, Floresta Massif Boyacá. I Colombian Congress of Paleontology.

Statements of authenticity and/or integrity

The rocks constituting the Floresta Formation, housing these invaluable fossils, are predominantly comprised of weathered and exposed mudstones and claystones. Despite their inherent fragility, the exposed conditions of these rocks in various paleontological localities prove to be conducive to scientific research and educational outreach. This is attributable to the ability to observe the most pertinent characteristics of each rock formation.

It's noteworthy that a significant number of fossils collected from these sites are accessible to the public through local museums, including the Museo de la Vida in Floresta, Boyacá, the Museo de los Andes in Socha, Boyacá, and the Museo de Ingeniería Geológica at the Universidad Pedagógica y Tecnológica de Colombia in Sogamoso, Boyacá. These museums serve as valuable repositories, enabling wider public engagement and education regarding the rich paleontological heritage of the Floresta Formation.

Furthermore, despite past extraction activities of fossil pieces, the sites retain substantial fossiliferous potential. This underscores the importance of future prospective efforts in systematically exploring the stratigraphic intervals across the Floresta sites. Continued research and exploration are essential for uncovering new insights, expanding our understanding of the region's paleontological significance, and ensuring the preservation of this valuable scientific and educational resource.

Within the Land Management Scheme (Esquema de Ordenamiento Territorial, EOT) of the municipality of Floresta, Boyacá, this instrument refers to the geological and fossiliferous wealth of the region with the approach of project 18.2 focused on geological tourism through the Eco-Geo-Archaeo-Routes, a Paleontological Museum and Ecological Tourism. Additionally, by means of Agreement N. 011 of the Floresta Municipal Council, it declares and recognizes the paleontological, geological and archaeological findings of the municipality of Floresta Boyacá, as assets of cultural interest, part of the municipal heritage and orders to advance procedures and actions to ensure their protection, conservation, rehabilitation, dissemination and good management; in addition to declaring the municipality of Floresta as municipal geological heritage given its national and international scientific importance.This state documents allow the paleontological richness of these sites to be recognized for its conservation.

The initiatives aimed at conserving and protecting this valuable paleontological heritage are a testament to the proactive involvement of the community. These conservation efforts, now formalized through agreements with state entities, have roots in the community's own commitment to safeguarding and preserving its patrimony. The collaborative endeavor for the study, recognition, protection, and conservation of this deposit has been a shared undertaking involving national, governmental, and municipal authorities, as well as active participation from the local community.

The Colombian Geological Survey (Servicio Geológico Colombiano) plays a crucial role in collective endeavors to preserve invaluable paleontological sites. The collaboration among the community and government support underscores a commendable synergy aimed at ensuring the sustainable conservation of these significant paleontological locations.

Within this framework, the Integral Management System for the Geological and Paleontological Heritage of the Nation has been implemented. Developed in coordination with local communities and national and regional authorities, this initiative seeks to guarantee the preservation of the paleontological deposit.

As part of this comprehensive commitment, the Colombian Geological Survey has provided support to collections and museums housing paleontological material from this deposit. Additionally, specific actions have been taken to protect the paleontological heritage, including the preparation of a national declaratory dossier and the assessment of possibilities for establishing suitable protection measures.

This strategy reflects a holistic approach that goes beyond scientific research, addressing the safeguarding of the cultural and environmental richness associated with these paleontological sites. The close collaboration between the Colombian Geological Survey, local communities, and authorities underscores the importance of effective coordination to ensure the long-term conservation of this invaluable geological and paleontological heritage.

Comparison with other similar properties

In the worldwide panorama of paleontological sites, various locations stand out for their significant contribution to the understanding of life during the Devonian period. Among them, Miguasha National Park in Canada, recognized as a UNESCO World Heritage site, stands out as the epicenter of sarcopterygians, the precursors to tetrapods. Germany, with the Hunsrück site, reveals exceptionally preserved marine fossils, while in Scotland, the Rhynie Chert site provides a unique glimpse into the early terrestrial plants and arthropods. Australia, with the Gogo site, presents a notable diversity of Devonian fishes, including Materpiscis, the oldest vertebrate with parental care. In the United States, the Red Hill site in Pennsylvania plays a crucial role in the study of the fish-to-tetrapod transition, housing fossils such as Hynerpeton and Hyneria. Finally, the Chengjiang site in China stands out as one of the oldest and most diverse, preserving a wide range of Devonian organisms with soft tissues. In this global context, the Floresta Boyacá site in Colombia will be examined for its potential nomination as a UNESCO World Heritage site, considering the significance of the uniqueness and diversity of the fauna represented in this deposit.

The Floresta Formation, situated in the Eastern Cordillera of the Andes in Boyacá, Colombia, offers an unparalleled window into the remote past of our planet, providing a valuable perspective on the evolution of life in South America during the Devonian.

With stratigraphic variability ranging from the Pragian to the Givetian, the Floresta Formation is characterized by the presence of a diverse marine fauna, including brachiopods, bryozoans, gastropods, trilobites, corals, pelecypods, ostracods, plant remains, and fishes (Barret, 1988)^[1]. These fossils, meticulously studied by Caster (1939), McNair (1941)^[2], and Moreno (2004), not only reveal exceptional biological richness but also the existence of endemic species previously unknown to science.

Highlighting the singularity of the Floresta Formation, in the first study conducted, Caster (1939) identified 49 species and varieties of brachiopods, assigned to 37 genera, of which 5 genera and 23 species were cataloged as new. This unique contribution to the global paleontological heritage emphasizes the importance of this deposit as a natural laboratory for understanding Devonian biodiversity and initiates a rich geoscientific tradition that has attracted multiple researchers worldwide for 85 years.

From a comparative perspective, the Floresta Formation shows notable similarities with the Appalachian Basins in North America and locations in Europe (Barret, 1988). This biogeographic connection suggests significant evolutionary links and supports the idea that, during the Late Devonian, South America experienced a period of transition towards greater faunal integration with other regions of the world.

The Colombia subprovince, according to Boucot (1988)^[3], is a testament to the biogeographic connections of Colombia with Venezuela and neighboring subprovinces of the Eastern American Domain. Defined by the presence of brachiopods and trilobites, this subprovince underscores the singularity of the Floresta Formation as a focal point in the biogeographic evolution of the region.

The Late Devonian in the Floresta Formation reveals a transition towards reduced provincialization, as immigrant species from the Old World and Malvinocaffric Domains become incorporated into the local fauna (Barret, 1988). This phenomenon, accompanied by climatic and ecological disturbances, highlights the evolutionary dynamics of the region.

The Floresta Formation, with its paleontological richness, not only provides a unique window into biological evolution but also sparks interest in paleogeography. The connection between northern South America and Laurasia, evidenced by similarities with the Appalachian Basins, suggests the existence of continental corridors during the Devonian, challenging models proposing extensive oceans between these land masses.

In conclusion, the Floresta Formation in Boyacá, Colombia, goes beyond being a mere paleontological site; it is a tangible testimony of life in the Devonian and a fundamental piece in the puzzle of the evolution of the South American continent. Its nomination for UNESCO World Heritage not only consecrates its scientific value but also underscores its crucial role in understanding the geological and biological history of planet Earth.

^[1] Barret, S. F. (1988). The devonian system in Colombia. Canadian Society of Petroleum Geologists. Memoria 14, 705-717 p.

^[2] McNAIR (1940): Devonian Bryozoa from Colombia. Bulletins of American Paleontology Vol. 25. New York.

^[3] Boucot, A. J. (1988) Devonian biogeography: An update. Canadian Society of Petroleum Geologists & Department of Zoology, Oregon State University. Memoria 14 211-227 p.