Late Oligocene–Early Miocene paleosols of distal fluvial systems, Ebro Basin, Spain

Hamer, Jessica M. M.; Sheldon, Nathan D.; Nichols, Gary; Collinson, Margaret E.

doi:10.1016/j.palaeo.2006.10.016

Cited by 62 publications

(37 citation statements)

References 34 publications

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“…Here, we turn to comparison between the quantitative MAP values and paleobotanical estimates of MAP for the study area. The paleobotanical assessment follows other workers who have used paleobotany to evaluate the validity of paleoprecipitation calculated from paleosol weathering indices (e.g., Sheldon et al, 2002;Hamer et al, 2007). The paleosol MAP values all are derived from the Nordt and Driese (2010) method and have the standard error for that technique.…”

Section: Comparison To Other Precipitation Proxiesmentioning

confidence: 99%

Evaluating the use of weathering indices for determining mean annual precipitation in the ancient stratigraphic record

Adams

Kraus

Wing

2011

Palaeogeography, Palaeoclimatology, Palaeoecology

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Section: Comparison To Other Precipitation Proxiesmentioning

confidence: 99%

Evaluating the use of weathering indices for determining mean annual precipitation in the ancient stratigraphic record

Adams

Kraus

Wing

2011

Palaeogeography, Palaeoclimatology, Palaeoecology

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“…Patchiness in C 4 distribution and expansion even during times of climatic quiescence during the Miocene suggests that local and regional factors such as fire regime, biodiversity, topography, and seasonality, which affect modern grassland distribution, were also important factors in historic grassland expansion and distribution. Ant nest trace fossil (e.g., Hasiotis, 2004;Hamer et al, 2007). Phytolith-isotope sample offsets are for readability purposes; they are derived from the same samples and horizons.…”

Section: Discussionmentioning

confidence: 99%

“…2C), but were generally present as kerogenized organic rootlets. A large ant nest trace fossil (e.g., Hasiotis, 2004;Hamer et al, 2007) was also found in the caprock ( Fig. 2D; Hamer, 2009) and in a low bluff stratigraphically below the main section.…”

Section: Trace Fossilsmentioning

confidence: 95%

Regional-scale variability in the spread of grasslands in the late Miocene

Chen

Smith

Sheldon

et al. 2015

Palaeogeography, Palaeoclimatology, Palaeoecology

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Highlights• C 3 and C 4 plant abundances are reconstructed using phytoliths and δ 13 C org values • Penecontemporaneous sites from the same region show different temporal patterns • Expansion of C 4 in the Northern Rocky Mts. does not match the global pattern • Elevation places a primary control on C 4 abundance Abstract A new paleovegetation reconstruction based on both phytolith and paleosol carbon isotopic data is presented for the middle-late Miocene (11.2-9.5 Ma) of southwestern Montana. Both sources of data indicate an open-habitat, C 3 grassland ecosystem with a small C 4 component (<10%).However, while a penecontemporaneous record from further south within the same region indicated significant spatial and temporal variability in C 4 abundance, the new record indicates relatively little change either in space or in time. Because paleoclimatic conditions reconstructed at these two sites are the same, we hypothesize that other ecological factors controlled C 4 abundance across the region. The relative abundance of C 3 and C 4 plants in the Miocene is the same as in modern environments at both sites, suggesting that their distribution was likely established by the middle-late Miocene. This is consistent with the idea that paleoelevation was also similar, which agrees with independent constraints on the regional tectonic history. TheMontana records indicate a more limited distribution of C 4 vegetation than is observed in the Great Plains and elsewhere globally, as well as variable timing in the shift to C 4 dominance in ecosystems. Taken together, this local, regional, and global variability during a time of little or no climate change suggests that C 4 distribution and expansion was driven by local, rather than global, environmental factors.

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“…Unfortunately, paleosols are not well developed in the studied outcrops 596 (Nichols and Hirst, 1998;Hamer et al, 2007b), and when present they do not generate 597 prominent features, often remaining buried under debris or covered by vegetation. Thus, the 598 scarce paleosol exposures found in the outcrops are not laterally continuous enough to allow 599 us to calculate well-constrained planes from them.…”

Section: Such a Parallel Relationship With All The Horizons Of An Outmentioning

confidence: 99%

Unlocking the correlation in fluvial outcrops by using a DOM-derived virtual datum: Method description and field tests in the Huesca fluvial fan, Ebro Basin (Spain)

Calvo

Ramos

2015

Geosphere

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8Adequate characterization of depositional architecture is of great importance when 9 studying fluvial outcrops as reservoir analogs. The complex three-dimensional (3D) 10 distribution and lateral/vertical relationships of sandstone bodies require a high degree of 11 stratigraphic control in order to make a proper assessment of the distribution and connectivity 12 of the reservoir facies. This demands the use of reliable correlation datums. Unfortunately, 13 clear marker beds (e.g., ash/coal layers and paleosols) are not always available in fluvial 14 outcrops, and when present they are often covered by vegetation or debris that prevents their 15 tracking over long distances. 16A new method to achieve highly accurate and semiautomatic correlations within 17 fluvial DOMs (Digital Outcrop Model) is presented in response to the need for further 18 correlation procedures, especially in the absence of suitable datums. The method is based on 19 the hypothesis that the average depositional paleosurface of a sedimentary system can be 20represented by a plane at outcrop scale. If this assumption is valid, this plane can be used as a 21Virtual Datum to identify along the DOM the sediments that were deposited simultaneously. 22The method was tested and applied successfully within two kilometer-scale outcrops 23 of the Huesca Fluvial Fan (Early Miocene, N Spain), where the Virtual Datum provided 24 accurate correlations regardless of stratigraphic or topographical complexities. Moreover, the 25 entire sedimentary successions were automatically subdivided into the desired stratigraphic 26 intervals by only moving the Virtual Datum vertically. These intervals can be subsequently 27 isolated to facilitate the detection of subtle variations and trends of their fluvial properties. 28

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Late Oligocene–Early Miocene paleosols of distal fluvial systems, Ebro Basin, Spain

Cited by 62 publications

References 34 publications

Evaluating the use of weathering indices for determining mean annual precipitation in the ancient stratigraphic record

Evaluating the use of weathering indices for determining mean annual precipitation in the ancient stratigraphic record

Regional-scale variability in the spread of grasslands in the late Miocene

Unlocking the correlation in fluvial outcrops by using a DOM-derived virtual datum: Method description and field tests in the Huesca fluvial fan, Ebro Basin (Spain)

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