Geology of the Walla Walla Area: Geology of the Walla Walla Area Dr. John D Winter
Department of Geology The French use the term “Terroir” to describe the complex interplay of temperature, sunshine, rainfall, soil, bedrock, viticultural practice, and other physical factors that influence the character and quality of wine
Slide2: Defined by elevation contour on S and E, and by lines approximating drainage divide on the N
Revised effective April 27, 2001
VAs defined by US Bureau of Alcohol, Tobacco, and Firearms- define by geography
Appelations of France defined in terms of wine characteristics
The Modern Plates: The Modern Plates
Three types of plate boundaries: Three types of plate boundaries
Three types of plate boundaries: Three types of plate boundaries
Age of the ocean crust: Age of the ocean crust
Hot Spots : Hot Spots
Hot Spots : Hot Spots
Convergent boundary: Convergent boundary Three sub-types
Ocean-Continent
Ocean-Ocean
Continent-Continent
Can you name an example of each?
Plate Tectonics in the Pacific Northwest: Plate Tectonics in the Pacific Northwest
Igneous Processes: Igneous Processes
The Edge of the North American Craton: The Edge of the North American Craton Mantle has low Rb which 87Sr over time, so low 87/86
Old continental crust has high Rb so high 87/86
Terranes of NE Oregon: Terranes of NE Oregon
Terranes of NE Oregon: Terranes of NE Oregon
Terranes of NE Oregon: Terranes of NE Oregon
Terranes of NE Oregon: Terranes of NE Oregon
Filling of the Columbia Embayment: Filling of the Columbia Embayment Westward roll-back of subduction
Fills Columbia Embayment
Stabilized near present location for ~ 40 Ma
Cascade range:
Uplift affects climate on east side
Volcanoes supply ash to winds and area
The Columbia River Basalts: The Columbia River Basalts
The Columbia River Basalts: The Columbia River Basalts
The Columbia River Basalts: The Columbia River Basalts Aerial extent of the N2 Grande Ronde flow unit (approximately 21 flows).
The Columbia River Basalts: The Columbia River Basalts Location of the exposed feeder dikes red) and vents (blue V's) of the southeastern portion of the Columbia River Basalts.
Slide22: WW CRBs probably result from SRP-Yellowstone hot-spot- difficult to explain northward deflection
The Columbia River Basalts: The Columbia River Basalts Basalts yield excellent soils in Hawaii and other tropical areas where rainfall is high and the climate is warm
Our soils in WW are not derived from the underlying basalts-an unusual feature
Continental Glaciation ~ 125,000 until 13,000 years ago: Continental Glaciation ~ 125,000 until 13,000 years ago
Continental Glaciation Wind-blown Loess deposits: Continental Glaciation Wind-blown Loess deposits
Continental Glaciation Wind-blown Loess deposits: Continental Glaciation Wind-blown Loess deposits Palouse Hills to north of WW: > 10,000 km2 and up to 75m thick (depends on sub-loess topography)
The Great Floods ~ 12,000 years ago: The Great Floods ~ 12,000 years ago Ice dam founders and releases up to 2500 km3 of water out across the plateau
The Great Floods ~ 12,000 years ago: The Great Floods ~ 12,000 years ago J Harlan Bretz in 1930’s- a controversial proposal
The Great Floods ~ 12,000 years ago: The Great Floods ~ 12,000 years ago
The Great Floods ~ 12,000 years ago: The Great Floods ~ 12,000 years ago
The Great Floods ~ 12,000 years ago- Burlingame Canyon: The Great Floods ~ 12,000 years ago- Burlingame Canyon Suggests up to 90 individual floods
WW received silts as “slackwater” deposits
Sediments range from gravels near Wallula to massive silts and sands toward Blue Mts
Winds continue to redistribute loess, silts, ash, etc.
Uplift of Blue Mts. Erosion by river system: Uplift of Blue Mts. Erosion by river system Mill Creek, Cottonwood, Birch Creek...Walla Walla River
Valley erosion in Blues ® floodplain sediments in WW valley
Walla Walla River Floodplain: Walla Walla River Floodplain Note Horse Heaven Hills- anticline of folded CRBs
Surface geological units : Surface geological units Note old WWVA boundaries- pre-2000 vineyards are in black
Strong correlation between units and elevation (also climate)
Basalts at highest elevations and where erosion exposes them
Loess at higher elevations than slackwater deposits (north and on Blues-Horse Heaven Hills)- mostly silt
Slackwater deposits: mostly sand and silt in WWVA
Loess and slackwater silts are glacial- derived from Canada- qtz-feldspar..not basaltic
Floodplain at lowest elevation-locally cobbles, gravel, sand, silt, clay- highly variable From Meinert and Busacca, 2000. Geoscience Canada, 27, 149-170.
Slide36: Soil textural classes WW very low in clay except in some areas of the WW River floodplain
Soil Types : Soil Types From Meinert and Busacca, 2000. Geoscience Canada, 27, 149-170. ~75 soil types in WW Soil Survey, can lump into ~8 groups (remember strong elevation-rainfall gradient too)
1- Cobble-loam-silt of floodplains and terraces of WW River and tributaries: long used for orchards- most vineyards now on the terraces with thin loess
Well-drained, and low organics- permits good control of grape vigor by management of water and nutrients
2- Loamy to silty in same floodplain-terrace areas
Poorly-drained, saline and alkaline- good for onions- Three Rivers on a well-drained terrace close to these
3- Loess over slackwater deposits on dissected terraces and uplands
Well-drained and silty Woodward Canyon Vineyard
Where loess thin (<60 cm) and low elevation cost of water may be a problem
4- Similar to 3- Loess over slackwater on dissected terraces
Silty, uniform, low to mod organic matter- extensive vineyards
5- Excessively drained sandy soils of dunes with < 30 cm/yr rain some juice grapes
6- Silty soils of deep loess on uplands 20-38 cm/yr rainfall
7- Silty soils of deep loess on uplands 38-58 cm/yr rainfall- more organics
8- Loamy to cobbly well-drained soils on steep mountain slopes- Figgins Mill Creek Upland Vineyard is only one yet
Wind and rainfall patterns: Wind and rainfall patterns From Meinert and Busacca, 2000. Geoscience Canada, 27, 149-170.
SW-NE Cross Section : From Meinert and Busacca, 2000. Geoscience Canada, 27, 149-170. SW-NE Cross Section WW vineyards on four fundamentally different substrates: slackwater terrace, loess, river gravel, and floodplain silt
Majority are in loess, either thick over basalt or thin over slackwater silts (which in turn are on basalt)
Again, well-drained silts with low organics allow the vintner to manage moisture and nutrients
Overly fertile floodplain soils develop strong vegetal flavors
Good slopes allow good airflow too- colder air sinks away so fewer frost problems
Cristophe Baron’s Caillouxe – searched with Kevin Pogue for very cobbly floodplain area- Forces roots deep, heated cobbles radiate, calcic soils stress vines combine to -> very concentrated fruit
Some Examples: Some Examples From Meinert and Busacca, 2000. Geoscience Canada, 27, 149-170.
Examples: Examples Pepper Bridge cabernet on thin loess Vineyard-covered “island” of slackwater deposits on WW River floodplain Cottonwood Creek vineyard chardonnay grapes on floodplain silts over gravel From Meinert and Busacca, 2000. Geoscience Canada, 27, 149-170.
Examples: Examples Caillouxe vineyard syrah on floodplain gravels. E shows trench and deep roots. From Meinert and Busacca, 2000. Geoscience Canada, 27, 149-170.
Examples: From Meinert and Busacca, 2000. Geoscience Canada, 27, 149-170. Examples Seven Hills on 2 meters of loess (over slackwater deposits) Canyon-bottom floodplain soils are better for fruity wines, such as Biscuit Ridge Gewurtztraminer) Mill Creek Upland vineyard tries out the higher-elevation loess Generalizations:
Low-precipitation during growing season, low organics, well-drained silts allows the vintner to control moisture and nutrients to develop vigor and complexity (and yield)
Highest quality vineyards lower their yield to 2-3 tons/acre (compared to 4-5 ton statewide average)
W ® E variation in elevation & rainfall, plus variations in soils, drainage, organic content, water table level of loess, slackwater deposits, floodplain ® Rich diversity of Terroirs
Latitude affects summer sunlight and temperatures (day and night)
Unique geological and soil features in WW suggest that our wines “may develop flavor and quality characteristics that set them apart from other wine-producing areas”