| 1. |
- Pujalte, Victoriano, et al.
(author)
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Integrative stratigraphy and climatic events of a new lower paleogene reference section from the betic cordillera : Río gor, Granada province, se Spain
- 2017
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In: Spanish Journal of Paleontology. - 2255-0550. ; 32:1, s. 185-206
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Journal article (peer-reviewed)abstract
- Research interest in the early Paleogene was greatly enhanced after the recognition of several short-lived warming events in that period (hyperthermals), considered ancient analogues of the ongoing warming of the Earth climate. In the Caravaca and Alamedilla sections, the previously most studied lower Paleogene sections of the Subbetic Zone (Betic Cordillera), only the most prominent of these hyperthermals had been located, the so-called Paleocene/Eocene Thermal Maximum. The Río Gor section, though less studied, is found to comprise a lower Paleogene succession that is more expanded and complete than Caravaca and Alamedilla; it contains record of the Early Late Paleocene and Paleocene/Eocene Thermal Events, and at least one additional Eocene hyperthermal, thus offering an excellent opportunity to study these climatic events in the Subbetic Zone. Study of the Río Gor section is still in progress, this paper summarizing the state-of-the art of ongoing research.
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| 2. |
- Pujalte, Victoriano, et al.
(author)
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Microcodium-rich turbidites in hemipelagic sediments during the Paleocene–Eocene Thermal Maximum : Evidence for extreme precipitation events in a Mediterranean climate (Río Gor section, southern Spain)
- 2019
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In: Global and Planetary Change. - : Elsevier BV. - 0921-8181. ; 178, s. 153-167
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Journal article (peer-reviewed)abstract
- An expanded record (~14 m)of the Paleocene–Eocene Thermal Maximum (PETM), a transient period of extreme global warming that occurred ~56 million years ago, has been found based on calcareous nannofossil and foraminifera stratigraphy in the deep marine Río Gor section, Subbetic Zone, SE Spain. During the early Palaeogene the Subbetic Zone was situated at a mid-palaeolatitude (~32° N), in the NW margin of the Tethyan Ocean. The most prominent features of the studied PETM interval are a significant increase in the proportion of palygorskite, a concurrent decrease in kaolinite and a high content in resedimented Microcodium remains, all of which imply arid/semiarid conditions, one of the distinctive features of the Mediterranean climate. The analysis of the event therefore provides new insights on the hydrological changes induced by the PETM in this climate. Microcodium remains mainly occur at Río Gor in ~450 thin-bedded turbidites, but also occurs redistributed by bioturbation throughout the entire PETM interval, and several centimetres below and above it. Microcodium has a very negative δ 13 C carbon isotope composition (from −8‰ to −20.7‰), and therefore distorts the global carbon isotopic signature of this thermal event at Río Gor. The increase in palygorskite indicates an intensification of aridity in the study area during the PETM. The Microcodium formed in or around roots of plants growing in subaerially exposed, uplifted massifs of Jurassic carbonates adjacent to the Río Gor area. The resedimentation in the deep sea as turbidites required major runoff episodes after heavy rainfalls. The concurrence of increased aridity and frequent episodes of precipitation extremes demonstrates that the PETM greatly enhanced the typical seasonal contrast of the Mediterranean climate in the Subbetic Zone.
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| 3. |
- Schmitz, Birger, et al.
(author)
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The Global Stratotype Sections and Points for the bases of the Selandian (Middle Paleocene) and Thanetian (Upper Paleocene) stages at Zumaia, Spain
- 2011
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In: Episodes. - 0705-3797. ; 34:4, s. 220-243
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Journal article (peer-reviewed)abstract
- The global stratotype sections and points for the bases of the Selandian (Middle Paleocene) and Thanetian (Upper Paleocene) stages have been defined in the coastal cliff along the Itzurun Beach at the town of Zumaia in the Basque Country, northern Spain. In the hemipelagic section exposed at Zumaia the base of the Selandian Stage has been placed at the base of the Itzurun Formation, ca. 49 m above the Cretaceous/Paleogene boundary. At the base of the Selandian, marls replace the succession of Danian red limestone and limestone-marl couplets. The best marine, global correlation criterion for the basal Selandian is the second radiation of the important calcareous nannofossil group, the fasciculiths. Species such as Fasciculithus ulii, F. billii, F. janii, F. involutus, F. pileatus and F. tympaniformis have their first appearance in the interval from a few decimetres below up to 1.1 m above the base of the Selandian. The marker species for nannofossil Zone NP5, F. tympaniformis, first occurs 1.1 m above the base. Excellent cyclostratigraphy and magnetostratigraphy in the section creates farther correlation potential, with the base of the Selandiatz occuring 30 precession cycles (630 kyr) above the top of magnetochron C27n. Profound changes in sedimentology related to a major sea-level fall characterize the Danian-Selandian transition in sections along the margins of the North Atlantic. The base of the Thanetian Stage is placed in the same section ca. 78 m above the Cretaceous/Paleogene boundary. It is defined at a level 2.8 m or eight precession cycles above the base of the core of the distinct clay-rich interval associated with the Mid-Paleocene Biotic Event, and it corresponds to the base of magnetochron C26n in the section. The base of the Thanetian is not associated with any significant change in marine micro-fauna or flora. The calcareous nannofossil Zone NP6, marked by the first occurrence of Heliolithus kleinpelli starts ca. 6.5 m below the base of the Thanetian. The definitions of the global stratotype points for the bases of the Selandian and Thanetian stages are in good agreements with the definitions in the historical stratotype sections in Denmark and England, respectively.
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