Late Miocene climate and life on land in Oregon within a context of Neogene global change

Retallack, Gregory J.

doi:10.1016/j.palaeo.2004.07.024

Cited by 21 publications

(8 citation statements)

References 70 publications

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“…Most proxy records in the western US for the Neogene warm periods indicate wetter than modern with the exception of Thompson (1991) and Retallack (2004), which suggest drier conditions in the Pacific Northwest in the late Pliocene. The simulated response of precipitation to permanent El Niño-like SSTs captures the wetter-than-present conditions inferred from the proxy data.…”

Section: Model Proxy Comparisonmentioning

confidence: 99%

“…The simulated response of precipitation to permanent El Niño-like SSTs captures the wetter-than-present conditions inferred from the proxy data. The regional model simulates more wide-spread moistening in the western and central US than the global model, and the drier conditions over the Pacific Northwest indicated by Thompson (1991) and Retallack (2004) are resolved in the regional model, but not in the global model (Fig. 1).…”

Section: Model Proxy Comparisonmentioning

confidence: 99%

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Implications of the permanent El Niño teleconnection "blueprint" for past global and North American hydroclimatology

Goldner¹,

Huber²,

Diffenbaugh

et al. 2011

Clim. Past

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Abstract. Substantial evidence exists for wetter-thanmodern continental conditions in North America during the pre-Quaternary warm climate intervals. This is in apparent conflict with the robust global prediction for future climate change of a northward expansion of the subtropical dry zones that should drive aridification of many semiarid regions. Indeed, areas of expected future aridification include much of western North America, where extensive paleoenvironmental records are documented to have been much wetter before the onset of Quaternary ice ages. It has also been proposed that climates previous to the Quaternary may have been characterized as being in a state with warmer-than-modern eastern equatorial sea surface temperatures (SSTs). Because equatorial Pacific SSTs exert strong controls on midlatitude atmospheric circulation and the global hydrologic cycle, the teleconnected response from this permanent El Niño-like mean state has been proposed as a useful analogue model, or "blueprint", for understanding global climatological anomalies in the past. The present study quantitatively explores the implications of this blueprint for past climates with a specific focus on the Miocene and Pliocene, using a global climate model (CAM3.0) and a nested high-resolution climate model (RegCM3) to study the hydrologic impacts on global and North American climate of a change in mean SSTs resembling that which occurs during modern El Niño events. We find that the global circulation response to a permanent El Niño resembles a large, long El Niño event. This state also exhibits equatorial super-rotation, which would represent a fundamental change to the tropical circulations. We also find a southward shift in winter storm tracks in the Pacific and Atlantic, which affects precipitation and temperature over the mid-latitudes. In addition, summertime precipitation increases over the majority of the continental UnitedCorrespondence to: A. Goldner (agoldner@purdue.edu)States. These increases in precipitation are controlled by shifts in the subtropical jet and secondary atmospheric feedbacks. Based on these results and the data proxy comparison, we conclude that a permanent El Niño like state is one potential explanation of wetter-than-modern conditions observed in paleoclimate-proxy records, particularly over the western United States.

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Section: Model Proxy Comparisonmentioning

confidence: 99%

Section: Model Proxy Comparisonmentioning

confidence: 99%

Implications of the permanent El Niño teleconnection "blueprint" for past global and North American hydroclimatology

Goldner¹,

Huber²,

Diffenbaugh

et al. 2011

Clim. Past

View full text Add to dashboard Cite

show abstract

“…The moist air moving inland across the Pacific Northwest from over the Pacific Ocean would not have been obstructed by these mountain ranges; that would have contributed to the wet and humid climates that were present in these now-arid regions. Dillhoff et al (2014) proposed that the warm and mild climate of the Pacific Northwest during the Miocene acted as a climatic refugium for some taxa amidst the increasing seasonality and cooling temperatures of the late Miocene, which ultimately led to the emergence of grasslands throughout the interior of North America (Retallack et al, 2002;Retallack, 2004;Strömberg, 2005;Retallack, 2007;Harris et al, 2017).…”

Section: Discussionmentioning

confidence: 99%

The Miocene Red Lake macroflora of the Deadman River Formation (Chilcotin Group), Interior Plateau, British Columbia, Canada

Greenwood

West

Basinger

2020

Acta Palaeobotanica

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Despite early interest in Neogene floras, primarily Miocene sites associated with Mio–Pliocene volcanic deposits of the Interior Plateau of British Columbia, few systematic accounts of the Miocene macrofloras of British Columbia – or elsewhere in non-Arctic Canada – have been published since the pioneering studies of J.W. Dawson and his contemporaries in the late 19th century. In this report, the Red Lake macroflora from sediments of the middle Miocene Deadman River Formation exposed in the Red Lake diatomite mine north of Kamloops, British Columbia, is illustrated, and a preliminary assessment presented, along with a brief review of Miocene floras from British Columbia and the U.S. Pacific Northwest. The Red Lake macroflora contains rare Ginkgo leaves, shoots of Cupressaceae (Cupressinocladus, Metasequoia, Taxodium) and shoots and seeds of Pinaceae (Pseudotsuga, Tsuga), maple (Acer) seeds and leaves, Liquidambar (fruit), Trochodendraceae (Zizyphoides auriculata leaves, Nordenskioeldia interglacialis fruits), leaves of 4 species of red and white oaks (Quercus columbiana, Q. prelobata, Q. pseudolyrata, Quercus sp.), leaves of an alder (Alnus harneyana) and birch (Betula thor), chestnut (Castanea spokanensis), beech (Fagus pacifica), sycamore (Platanus dissecta), elm (Ulmus speciosa), leaves of unidentified taxa, fruits of Tilia pedunculata (Malvaceae) and fruits and inflorescences of other unidentified taxa, and leaves of a reed or rush (indet. monocot). The Red Lake middle Miocene climate reconstructed from leaf physiognomy was temperate and mesic, with mean annual temperature ~11–13°C, mild winters (coldest month mean temperature ~3°C), mean annual precipitation 170 −51/+73 cm/yr, and growing season precipitation ~92 cm, with moderate seasonality of precipitation (three wettest months ~51 cm vs. three driest months ~25 cm). The Red Lake flora shows similarities to middle to late Miocene floras from the U.S. Pacific Northwest (i.e., richness in oaks) but is of much lower diversity and lacks key elements common to many of the contemporaneous U.S. Miocene floras (e.g., foliage of Pinaceae esp. Pinus), and is missing taxa detected in the microflora, a pattern likely due to sampling effectiveness at the Red Lake Mine and sampling of different lithofacies for macro- and microfloras.

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“…The western US has received substantial attention by climate scientists and geologists because of its susceptibility to large-scale droughts (Cook et al, 2004;Cole et al, 2002). Most proxy records in the western US for the Neogene warm periods indicate wetter than modern with the exception of Thompson (1991) and Retallack (2004), which suggest drier conditions in the Pacific Northwest in the late Pliocene. The simulated response of precipitation to permanent El Niñolike SSTs captures the wetter-than-present conditions inferred from the proxy data.…”

Section: Model Proxy Comparisonmentioning

confidence: 99%

“…The simulated response of precipitation to permanent El Niñolike SSTs captures the wetter-than-present conditions inferred from the proxy data. The regional model simulates more wide-spread moistening in the western and central US than the global model, and the drier conditions over the Pacific Northwest indicated by Thompson (1991) and Retallack (2004) are resolved in the regional model, but not in the global model (Fig. 1).…”

Section: Model Proxy Comparisonmentioning

confidence: 99%

Implications of the permanent El Niño teleconnection "blueprint" for past global and North American hydroclimatology

Goldner¹,

Huber²,

Diffenbaugh³

et al. 2011

Preprint

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Abstract. Substantial evidence exists for wetter-than-modern continental conditions in past warm climates. This is in apparent conflict with the robust global prediction for future climate change of a northward expansion of the subtropical dry zones that should drive aridification of many semiarid regions. Areas of expected aridification include much of Western North America, where extensive paleoenvironmental records from North America point to wetter conditions before the onset of Quaternary ice ages. It has been proposed that climates previous to the early Pliocene may have been characterized as being in a state with warmer-than-modern eastern equatorial sea surface temperatures (SSTs). Because Equatorial Pacific SSTs exert strong controls on midlatitude atmospheric circulation and the global hydrologic cycle, the teleconnected response from this permanent El Niño-like mean state has been proposed as a useful analogue model, or "blueprint", for understanding global climatological and hydrological anomalies in the past. The present study quantitatively explores the implications of this blueprint for past climates, using a global climate model (CAM3.0) and a nested high-resolution climate model (RegCM3) to study the hydrologic impacts of a permanent El Niño on global and North American climate. We find that the global circulation response to a permanent El Niño resembles a large, long El Niño event. However, this state also exhibits equatorial super-rotation, which would represent a fundamental change to the tropical circulations. We also find intensification and southward drift in winter storm tracks in the Pacific, which affects precipitation and temperature over the mid-latitudes via large shifts in atmospheric circulation. In addition, summertime precipitation increases over the majority of the continental United States, with these increases likely controlled by shifts in the subtropical jet and secondary atmospheric feedbacks. Based on these results, we conclude that a permanent El Niño is a good explanation of the Pre-Quaternary wetter-than-modern conditions observed in paleo proxy records, particularly over the Western United States.

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Late Miocene climate and life on land in Oregon within a context of Neogene global change

Cited by 21 publications

References 70 publications

Implications of the permanent El Niño teleconnection "blueprint" for past global and North American hydroclimatology

Implications of the permanent El Niño teleconnection "blueprint" for past global and North American hydroclimatology

The Miocene Red Lake macroflora of the Deadman River Formation (Chilcotin Group), Interior Plateau, British Columbia, Canada

Implications of the permanent El Niño teleconnection "blueprint" for past global and North American hydroclimatology

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Late Miocene climate and life on land in Oregon within a context of Neogene global change

Cited by 21 publications

References 70 publications

Implications of the permanent El Niño teleconnection &quot;blueprint&quot; for past global and North American hydroclimatology

Implications of the permanent El Niño teleconnection &quot;blueprint&quot; for past global and North American hydroclimatology

The Miocene Red Lake macroflora of the Deadman River Formation (Chilcotin Group), Interior Plateau, British Columbia, Canada

Implications of the permanent El Niño teleconnection &quot;blueprint&quot; for past global and North American hydroclimatology

Contact Info

Product

Resources

About

Implications of the permanent El Niño teleconnection "blueprint" for past global and North American hydroclimatology

Implications of the permanent El Niño teleconnection "blueprint" for past global and North American hydroclimatology

Implications of the permanent El Niño teleconnection "blueprint" for past global and North American hydroclimatology