Introduction and Explanatory Notes

Buffler, R.T; Schlager, W.; Pisciotto, K.A.

doi:10.2973/odp.proc.ir.101.101.1986

Cited by 8 publications

(2 citation statements)

References 23 publications

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“…In CLQ20 these laminae are mostly made by clay particles (Figures 6b, 6e, 7b, 7c, 7f, 8d, 8e, and 8f), but also some silt particles (Figures 8a and 8d) or biogenic particles, such as rare Thalassionema specimens (Figure 6c), or other species (Figure 8d). Coscinodiscus laminae: in this paper we use the definition “ Coscinosdiscus lamina” to indicate a diatomite (a hard pelagic sediment made by >30% of skeletal remains of diatoms and <30% silt and clay, as defined by Palmer et al., 1986) where Coscinodiscus (possibly Coscinodiscus asteromphalus; Table 1) is the dominant genus (>90%; Figures 4b, 4e, 5b, 5f, 5g, 5i, 5k, 5m, 8a, 8c, and 8g). Other rare components of these laminae are Actinocyclus octonarius (Table 1) specimens (Figure 4f), Thalassionema specimens (Figure 8b; Table 1) and rare terrigenous particles (Figure 4e).…”

Section: Resultsmentioning

confidence: 99%

Paleoceanographic Implications of Diatom Seasonal Laminations in the Upper Miocene Pisco Formation (Ica Desert, Peru) and Their Clues on the Development of the Pisco Fossil‐Lagerstätte

Gariboldi

Pike

Malinverno

et al. 2023

Paleoceanog and Paleoclimatol

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The detailed study of diatom laminations conducted by means of backscattered electron imaging serves as tool to unravel details of past ocean dynamics. In this paper we apply this method to the analysis of the diatomites of Cerro Los Quesos, Upper Miocene Pisco Fm, Peru. Numerous studies have been conducted on the Pisco Fm; however, a focus on its paleoceanographic significance is still lacking. In this work, we provide information on the oceanographic setting in the area at the time of diatomites deposition. The high abundance of deep‐living Coscinodiscus laminae, proceeded by either a mixed lamina or a terrigenous one, let us hypothesize a deep position of the thermocline during the deposition of the Pisco diatomites; together with the scarcity of Chaetoceros Hyalochaete spp. resting spores, this evidence confutes the belief that equals high biogenic silica content in marine sediments with enhanced upwelling. Conversely, the depositional setting of the Pisco Fm diatomites is more similar to what is known as “permanent El Niño” (or “El Padre”) state, meaning a constant weakened upwelling (or upwelling of nutrients‐poor waters). Climate modeling warns that an increase in atmospheric CO2 may lead to this mean state in the near future. Thanks to this study we also obtained refined information on the diatomites sedimentations rates. The comparison of the Pisco diatomites sedimentation rates with those of Quaternary diatomites gave strength to the hypothesis that the formation of the vertebrate Lagerstätte may have been enhanced, among others, by the so‐called “impact‐burial” mechanism.

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Section: Resultsmentioning

confidence: 99%

Paleoceanographic Implications of Diatom Seasonal Laminations in the Upper Miocene Pisco Formation (Ica Desert, Peru) and Their Clues on the Development of the Pisco Fossil‐Lagerstätte

Gariboldi

Pike

Malinverno

et al. 2023

Paleoceanog and Paleoclimatol

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“…6); these are probably fragments and spines of orosphaerid radiolarians (F. M. Maurrasse, pers, comm., 1987), although at least some objects may be sponge debris (Palmer, this volume). Sponge fragments usually have a hollow axial canal that can be used to distinguish them from radiolarian fragments; these canals are sometimes (but not [21][22][23][24][25][26][27][28][29][30][31][32][122][123][124][46][47][48][20][21][22][20][21][22][20][21][22][60][61][62][20][21][22] Palmer, Austin, and Schlager, 1986, for key to symbols), radiolarian abundance, radiolarian preservation, and radiolarian zones. B = barren; R = rare; F = frequent; C = common; A = abundant; P = poor; M = moderate; G = good.…”

Section: Site 628mentioning

confidence: 99%

Cenozoic Radiolarians from Ocean Drilling Program Leg 101, Bahamas (Sites 627 and 628) and Surrounding Region

Palmer¹

1988

Proceedings of the Ocean Drilling Program

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Radiolarians from two sites north of Little Bahama Bank (Sites 627 and 628) are correlated with assemblages from sites on the southeastern U.S. coastal plain and continental shelf and from DSDP Sites 391 and 534 in the Blake-Bahama Basin. Results show that deposition of biogenic silica-rich sediments occurred in this region from the late Oligocene through middle Miocene, although the record is interrupted by unconformities. Radiolarians help constrain the age of a mass-transported deposit at Site 627 that appears to be coeval with the Great Abaco Member of the Blake Ridge Formation. INTRODUCTION Radiolarians occur at only two sites on the Little Bahama Bank transect occupied during Leg 101, yet provide valuable information about regional Oligocene-Miocene depositional history when considered with results from nearby sites. In addition to examining material from Sites 627 and 628 (see Table 1), samples were examined from South Carolina coastal plain localities

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Historical pollution trends in a disturbed, estuarine sedimentary environment, SW Sweden

Brack

Stevens

2001

Environmental Geology

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Introduction and Explanatory Notes

Cited by 8 publications

References 23 publications

Paleoceanographic Implications of Diatom Seasonal Laminations in the Upper Miocene Pisco Formation (Ica Desert, Peru) and Their Clues on the Development of the Pisco Fossil‐Lagerstätte

Paleoceanographic Implications of Diatom Seasonal Laminations in the Upper Miocene Pisco Formation (Ica Desert, Peru) and Their Clues on the Development of the Pisco Fossil‐Lagerstätte

Cenozoic Radiolarians from Ocean Drilling Program Leg 101, Bahamas (Sites 627 and 628) and Surrounding Region

Historical pollution trends in a disturbed, estuarine sedimentary environment, SW Sweden

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