Ancient ocean floor surrounds Earth’s core, seismic imaging reveals

Published

2 years ago

April 17, 2023

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A massive ocean floor lurks near Earth’s core. Now, seismic imaging has revealed that it likely surrounds much — if not all — of the core.

This thin, dense layer is lodged roughly 2,000 miles (3,200 kilometers) below Earth’s surface, between the core and the planet’s middle layer, called the mantle. And it might encompass the entire core-mantle boundary, according to a study published April 5 in the journal Science Advances (opens in new tab) .

To study Earth’s interior, seismologists measure earthquake waves that zoom through the planet and then back out to Earth’s surface. By seeing how these waves change after passing through the different structures inside Earth, researchers can create a map of what Earth’s innards look like. Past research identified a handful of isolated pockets of dense ocean crust near the core. These pockets are called ultra-low-velocity-zone structures (ULVZs) because seismic waves travel very slowly through them.

“Only [approximately] 20% of the core-mantle boundary has been previously investigated for ULVZs, which have not been identified in all of these locations,” lead study author Samantha Hansen (opens in new tab) , an associate professor of geological sciences at The University of Alabama, told Live Science in an email. “It is possible that this anomalous material covers the entire core.”

In the new study, scientists placed seismic equipment at 15 stations located across Antarctica and collected data for three years.

Related: 450-mile-wide solid metal ball forms Earth’s innermost core, earthquake waves reveal

This study marks the first time that high-resolution imaging of the core-mantle boundary was made using data from the Southern Hemisphere. The layer itself is razor-thin compared with the core, which is 450 miles (724 km) across, and the mantle, which is roughly 1,800 miles (2,900 km) thick.

“The thickness does vary, depending on location,” Hansen said, with some spots measuring about 3.1 miles (5 km) thick and others 31 miles (50 km) in thickness.

This ancient ocean layer likely developed when Earth’s tectonic plates shifted, causing oceanic material to be carried into the planet’s interior at subduction zones, the areas where two plates collide and force one to dip beneath the other. Over time, “accumulations of subducted oceanic material collect along the core-mantle boundary and are pushed by the slowly flowing rock in the mantle,” according to a statement (opens in new tab) .

Researchers think the newly detected ULVZs are essentially “underground mountains” that allow heat to escape from Earth’s molten core, according to the statement.

“The presence of this layer could buffer heat flow across the core-mantle boundary, which is important because the temperature conditions in this portion of the Earth have been shown to strongly impact the planet’s magnetic field,” Hansen said.RELATED STORIES—’Completely new’ type of magnetic wave found surging through Earth’s core

—Rare primordial gas may be leaking out of Earth’s core

—Earth’s mantle has a gooey layer we never knew about

Chunks of this hidden ocean floor may also get swept up into mantle plumes — hot, upwelling jets of molten rock that fuel volcanic hotspots at the surface, such as in Hawaii, Hansen suggested.

“Further, since mantle plumes are largely controlled by the thermal conditions near the core-mantle boundary, the temperature influence of ULVZs may help dictate where plumes form,” Hansen said.

The research team plans to expand their study by examining data collected from all available seismic stations in Antarctica.

Business

Energy bills to rise again from January but spring falls to come, research firm Cornwall Insight forecasts

Published

28 mins ago

November 18, 2024

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Energy bills to rise again from January but spring falls to come, research firm Cornwall Insight forecasts

Energy bills are to rise again next year, according to a respected forecaster.

Costs from January to March are projected to rise another 1% to £1,736 a year for the average user, according to research firm Cornwall Insight.

The energy price cap, which sets a limit on how much companies can charge per unit of electricity, is also expected to rise, costing typical households an extra £19 a year.

It’s a further increase after energy costs rose 10% from October.

After the latest hike, there were hopes of a fall in the new year, but volatile wholesale gas and electricity markets are still above historic average costs.

Money blog: Supermarket-own champagne beats expensive brands in taste test

Prices have gone up due to supply concerns arising from Russia‘s war in Ukraine, and maintenance of Norwegian gas infrastructure.

But spring is expected to herald a reduction as is October 2025, Cornwall Insight said.

Every three months energy regulator Ofgem revises the cap based on wholesale costs.

The official January price cap announcement will be made on Friday.

It comes as millions of pensioners lost their automatic winter fuel allowance payment after the government means-tested the benefit.

Meanwhile, Cornwall Insight’s principal consultant Dr Craig Lowrey warned “millions” of households won’t heat their homes to “recommended temperatures, risking serious health consequences” with bills on the rise.

“With it being widely accepted that high prices are here to stay, we need to see action,” he said, suggesting options like cheaper rates for low-income homes, benefit restructuring, or other targeted support for the vulnerable “must be seriously considered”.

The energy price cap system is being reviewed by Ofgem with possible changes to the standing charge coming over the next year.

The long-lasting solution to high energy bills is the transition to UK-produced renewable power, the firm said.

“While there will be upfront costs, this shift is essential to building a sustainable and secure energy system for the future.”

UK

Masked burglars ‘raid’ Windsor Castle grounds ‘while William, Kate and children slept at home on estate’

Published

28 mins ago

November 18, 2024

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Masked burglars 'raid' Windsor Castle grounds 'while William, Kate and children slept at home on estate'

Masked burglars have stolen farm vehicles from the Windsor Castle estate while members of the Royal Family are believed to have been asleep nearby.

Two men scaled a 6ft fence on the night of 13 October and used a stolen truck to break through a security gate, The Sun first reported.

The pair then fled with a pick-up and a quad bike that were stored in a barn.

The King and Queen were not in residence.

But the Prince and Princess of Wales, along with their three children George, 11, Charlotte, nine, and six-year-old Louis were believed to have been in their home, Adelaide Cottage, on the estate, according to The Sun.

The family moved there in 2022.

In a statement, Thames Valley Police said: “At around 11.45pm on Sunday 13 October, we received a report of burglary at a property on Crown Estate land near to the A308 in Windsor.

“Offenders entered a farm building and made off with a black Isuzu pick-up and a red quad bike. They then made off towards the Old Windsor/Datchet area.

“No arrests have been made at this stage and an investigation is ongoing.”

On Christmas Day 2021, a man climbed a fence at Windsor Castle armed with a crossbow and claimed he wanted to kill Queen Elizabeth II.

Jaswant Singh Chail was handed a nine-year custodial sentence for treason, possession of an offensive weapon and making threats to kill.

UK

UK told to expect ‘disruptive snow’ as warnings cover large parts of country

Published

28 mins ago

November 18, 2024

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UK told to expect 'disruptive snow' as warnings cover large parts of country

The UK is braced for “disruptive snow” as yellow weather warnings cover large parts of the country until Tuesday – with the Met Office saying there is the “potential” for the alerts to be “escalated”.

The forecaster has warned up to 20cm of snow may accumulate in the worst affected areas as the country experiences its “first taste of winter”.

The Met Office has also told people to expect ice, cold temperatures and wintry showers this week.

Check the forecast in your area

A yellow warning for snow and ice is in place for much of the north of the country – covering areas in the East Midlands, Yorkshire, Wales and the north of England – from 7pm on Monday night to 10am on Tuesday morning.

Those in the impacted areas have been told power cuts are possible and mobile phone coverage might be affected.

The Met Office has said there is a “slight chance” some rural communities could be cut off and that bus and train services may be delayed or cancelled.

People are also warned to be careful not to slip or fall on icy surfaces.

The Met Office has said there will be bright spells across northern and eastern areas throughout today, but rain in the south and west will gradually spread northeastwards and turn to snow over northern hills.

Tom Morgan, Met Office meteorologist, said: “We could see some disruptive snow in the Pennine regions, in particular, the Peak District as well, especially Monday night, but we could well see some impacts lasting on until Tuesday morning’s rush hour.

“Even down to lower levels, we could well see some snow as well, so quite a bit of disruption possible by Tuesday morning, and then the week ahead is likely to stay cold nationwide, a windy day on Tuesday, and then winter showers through the week ahead.”

Mr Morgan said that despite a “mild” start to the month, the cold conditions are more typical of “mid-winter to late-winter”.

“What we can say is that it’s going to be very cold for the time of year, there will be widespread overnight frosts, and a few locations where there’s snow on the ground,” he continued.

Meanwhile, a yellow snow and ice weather warning that came into force at 4pm on Sunday will end at 11am this morning.

The warning covers the northern tip of Scotland and people there have been told there may be icy patches on some untreated roads, pavements and cycle paths.

The Met Office has said there is “potential” for both yellow warnings to be “escalated”.

In southern England, a typical maximum temperature for this time of year is 11C (52F), but daytime highs for the week ahead are forecast to be around 5C (41F), while some parts of Scotland will reach “only just above freezing”, Mr Morgan said.

The meteorologist said the public can best prepare for the wintry weather by checking their cars are suitable for icy and potentially snowy conditions and to take extra supplies including food, blankets and a fully charged mobile phone with them on journeys.

He added there were “likely” to be changes to the weather warnings in the coming days, and that “winter flurries” could be seen in the south of England later in the week.

Despite the cold conditions, the “whole of the UK” will enjoy more sunshine this week, the meteorologist added.

He said: “There’ll be some snow showers in the peripheries of the UK, particularly northern Scotland, and down the east and the west coast, but if you live inland and you live in the south, there’ll be lots of sparkly blue skies on the most days through Tuesday to Friday.”

It comes as a cold weather alert issued by the UK Health Security Agency, which was introduced at 9am on Sunday, will be in place until 9am on Thursday.

It covers a large area of England, north of Northhampton. The alert is triggered when there is a risk that healthcare services might face extra pressure and is designed to prepare those who are “particularly vulnerable” and “likely to struggle to cope”.