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Report of the JARE-54 and BELARE 2012-2013 joint expedition to collect meteorites on the Nansen Ice Field, Antarctica

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This paper reports on a joint expedition (JARE-54 and BELARE 2012-2013) that conducted a search for meteorites on the Nansen Ice Field, Antarctica, in an area south of the Sør Rondane Mountains (72°30′⊖73°S, 23°⊖25°E; elevation 2900⊖3000 m). The expedition took place over a period of 39 days during the austral summer, between 26 December 2012 and 2 February 2013. The team consisted of ten members: three researchers and one field assistant from the 54th Japanese Antarctic Research Expedition (JARE-54), and five researchers and one field assistant from the Belgian Antarctic Expedition (BELARE) 2012⊖2013. Previously, this area had only been searched by JARE-29. The team collected 424 meteorites, which had a total weight of about 70 kg. The search tracks of the ten members of the expedition were recorded using hand-held GPS units, and this allowed the distribution of meteorites within the searched area to be mapped. The resultant data will be useful for planning future expeditions and can be used to clarify the meteorite concentration mechanism on the ice field. This paper focuses on the activities of JARE-54 during the joint expedition.
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38 N. Imae et al.
󰐸󰐸
Report
Report of the JARE-54 and BELARE 20122013 joint expedition to
collect meteorites on the Nansen Ice Field, Antarctica
Naoya Imae1, 2 *, Vinciane Debaille3, Yukihisa Akada4, Wendy Debouge3,
Steven Goderis5, Geneviève Hublet3, Takashi Mikouchi6, Nadia Van Roosbroek3,
Akira Yamaguchi1, 2, Harry Zekollari5, Philippe Claeys5 and Hideyasu Kojima1, 2
54  20122013 
󰋂
1, 2 *Vinciane Debaille34Wendy Debouge3
Steven Goderis5Geneviève Hublet3 6Nadia Van Roosbroek3
1, 2Harry Zekollari5Philippe Claeys51, 2
(Received July 29, 2013; Accepted January 19, 2015)
要旨: 54  4 6
10 󰋂2012 12  2013 2
 7230󰮍73 2325
29003000 m󰋂 2012 12
26  2013 22 39  29 
󰋂
424  70 kg 󰋂 GPS 
󰋂󰋂


Abstract:This paper reports on a joint expedition (JARE-54 and BELARE 2012
2013) that conducted a search for meteorites on the Nansen Ice Field, Antarctica, in an area
south of the Sr Rondane Mountains (7230󰮍73S, 2325E; elevation 29003000 m).
The expedition took place over a period of 39 days during the austral summer, between 26
1   National Institute of Polar Research, Research Organization of
Information and Systems, Midori-cho 103, Tachikawa, Tokyo 190-8518.
2 
Department of Polar Science, School of Multidisciplinary
Sciences, SOKENDAI (The Graduate University for Advanced Studies), Midori-cho 103, Tachikawa, Tokyo
190-8518.
3 
Université Libre de Bruxelles, Département des Sciences de la Terre et de lEnvironnement,
CP160/02, Ave. F.D. Roosevelt 50, 1050 Brussels, Belgium.
4  present affiliation
Ariake Alpine Guide Union, Aisome
118671, Ikeda, Nagano 399-8602.
5 
Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium.
6 
Department of Earth and Planetary Science, The University
of Tokyo, 7
3
1 Hongo, Bunkyo-ku, Tokyo 113-0033.
Corresponding author. E-mail: imae@nipr.ac.jp
Vol. 59No. 138722015
Nankyoku Shiryo
(Antarctic Record), Vol. 59, No. 1, 3872, 2015
󰽦 2015 National Institute of Polar Research
39Report of the JARE-54 and BELARE 20122013 joint expedition to collect meteorites
December 2012 and 2 February 2013. The team consisted of ten members: three
researchers and one field assistant from the 54th Japanese Antarctic Research Expedition
(JARE-54), and five researchers and one field assistant from the Belgian Antarctic
Expedition (BELARE) 20122013. Previously, this area had only been searched by JARE-
29. The team collected 424 meteorites, which had a total weight of about 70 kg. The
search tracks of the ten members of the expedition were recorded using hand-held GPS
units, and this allowed the distribution of meteorites within the searched area to be mapped.
The resultant data will be useful for planning future expeditions and can be used to clarify
the meteorite concentration mechanism on the ice field. This paper focuses on the
activities of JARE-54 during the joint expedition.
1.Introduction
Many meteorites have been recovered from the bare ice fields of inland Antarctica.
The earliest finds were by the 10th Japanese Antarctic Research Expedition (JARE-10),
which collected nine meteorites from the bare ice field around the Yamato Mountains
(Yoshida et al., 1971). Since then, more than 17000 meteorites have been recovered by
JARE.
The only previous meteorite collection expeditions on the Nansen Ice Field (Fig. 1; 72
30󰮍73S, 2325E; elevation 29003000 m; 100140 km south of the Sør Rondane
Mountains) were those of JARE-29 (Naraoka et al., 1990; Yanai, 1993) and the Belgian
Antarctic Expedition (BELARE) of 20102011 (Goderis et al., 2011). The meteorites
collected around the Sør Rondane Mountains, mainly from the Nansen and Balchen Ice
Fields, are known as the Asuka meteorites (Kaiden et al., 2010; Tsuchiya et al., 2012; Yanai,
1993; Yanai et al., 1993). The JARE-29 winter party collected about 2000 Asuka
meteorites, including one huge specimen (46 kg; A-87251 LL6) and many rare meteorites,
including an angrite (Asuka (A)-881371), a lunar gabbro (A-881757), unique carbonaceous
chondrites of CH3 (A-881020, A-881541, and A-881691), a Rumuruti (A-881988), and
three mesosiderites (A-87106, A-881154, and A-882023). The first two joint meteorite
search projects conducted by JARE and BELARE recovered 678 Asuka 09 meteorites
(about 13 kg total weight) in 2009, and 230 Asuka 10 meteorites (about 6 kg total weight) in
2010 (Goderis et al., 2011; Tsuchiya et al., 2012). The number of collected meteorites
normally includes a few terrestrial rocks for each expedition and this is clarified during the
classification in the laboratory. In the paper, we use the collected number throughout the
paper.
Here, we report on the third joint expedition by JARE-54 and BELARE, which took
place in 20122013 with the aim of collecting Asuka meteorites, and has been preliminary
reported on by Imae et al. (2013) and Debaille et al. (2013). The meteorites were collected
from the Nansen Ice Field, and 424 meteorites (total weight about 70 kg) were collected,
including a large ordinary chondrite (about 18 kg), carbonaceous chondrites, and
achondrites. They are referred to as Asuka 12 meteorites. The average weight of the
meteorites was about 180 g, much heavier than those collected during the two previous joint
expeditions in the 20092011 and 20102011 austral summer seasons. Each of the
meteorites with a mass greater than 50 g will be halved and shared between Japan and
Belgium, as specified in the Memorandum of Understanding (MoU) contained in the plan
made for JARE-51 (51st Japanese Antarctic Research Expedition, 2009). The MoU
40 N. Imae et al.
between Japan and Belgium covering the processing of Asuka 12 meteorites, and other
collaborations on Antarctic meteorites, was updated in Brussels on 24 May 2013.
2.Team members and their roles for JARE
All joint expedition team members are listed in Table 1, and the roles of JARE team
members are listed in Table 2. Although all members of the joint expedition worked
together during the fieldwork, the Japanese and Belgian base camps were separate; the two
teams had a group dinner about once a week.
3.Pre-expedition preparation
Preparation for this expedition was mainly conducted by members of JARE-54. The
detailed plan was described by 54th Japanese Antarctic Research Expedition (2012) and
was summarized by Imae et al. (2012). The sequence of important components of the
preparation phase is listed in Table 3.
3.1.Safety training
Pre-expedition safety training for JARE-54 team members is summarized in Table 3.
Table 1. Team members consisting of four JARE members and six BELARE members.
41Report of the JARE-54 and BELARE 20122013 joint expedition to collect meteorites
3.2.Pre-expedition meetings of JARE and BELARE
3.2.1.In Brussels
Between 30 May and 1 June 2012, JARE members (NI and AY; see Table 1 for names)
met several times with the scientists and logistics staff of BELARE to discuss the length of
the expeditions stay on the Nansen Ice Field and the logistical support required. Meetings
were held on 30 May and 1 June at both Vrije Universiteit Brussel and Université Libre de
Bruxelles (ULB), and on 31 May at International Polar Foundation (IPF). Especially, the
time required for the meteorite search on the Nansen Ice Field was determined by taking
into consideration the area of the ice field and discussions with Alain Hubert of the IPF.
3.2.2.At National Institute of Polar Research (NIPR)
Meetings at NIPR included discussions of geoscience matters on 9 May and 16
October 2012 (see Chapter 1 of 54th Japanese Antarctic Research Expeditions (2012)
expedition plan), and discussions of safety issues on 29 October 2012 (see Chapter 3 of 54th
Japanese Antarctic Research Expeditions (2012) expedition plan).
Table 2. Roles of JARE-54 team members.
42 N. Imae et al.
Table 3. Summary of preparation and training for 20122013 meteorite search.
43Report of the JARE-54 and BELARE 20122013 joint expedition to collect meteorites
3.2.3.Dronning Maud Land Air Network (DROMLAN) flight schedules
Prof. Yoichi Motoyoshi of NIPR arranged schedules for outgoing (and return) flights
from Cape Town to Novolazarevskaya Air Base (Ilyushin-76) and then to Princess Elisabeth
Station (PES) (Basler Turbo) at the meetings with DROMLAN in April 2012 (St.
Petersburg, Russia) and July 2012 (Portland, Oregon, USA).
3.3.Planned itinerary
The Japanese and Belgian teams were to fly independently by commercial airlines to
Cape Town, South Africa, in early December 2012, from where DROMLAN operates
flights to and from Antarctica (Fig. 1a). The main supplies and equipment (food and
clothing; about 1000 kg) for the Japanese team would be sent in advance to the Cape Town
warehouse of the Antarctic Logistics Centre International (ALCI). Arrival of the joint
expedition team at the Russian Novolazarevskaya Air Base (Fig. 1a) on an Ilyushin-76
aircraft was scheduled for 6 December 2012, followed by feeder flights (Basler Turbo) to
PES on the same day (Fig. 1b and c). At PES, we were to prepare for our main meteorite
search and carry out a micrometeorite search in the Sør Rondane Mountains close to PES,
with logistical support from Belgium (Principal Investigator, Steven Goderis). The Belgian
support team was to set up base camp 1 (BC1; Fig. 1d) by using up to three large snow
vehicles (Prinoth snow tractors) to carry extra snowmobiles (Ski-Doo, BRP), fuel, foods,
sledges, and living quarters. After setting up BC1 (7253󰮍S, 2418󰮍E), the Belgian support
team was to return to PES with the snow tractors. We planned to spend about 23 days at
BC1 searching for meteorites within area B (Fig. 1d). We then planned to move to base
camp 2 (BC2; 7247󰮍S, 2451󰮍E), travelling by snowmobile with the Belgian logistics
support team. About 20 days were scheduled for our stay at BC2 to search for meteorites
within area C (Fig. 1d).
After completion of our meteorite search, we planned to return by retracing our
outward journey: from PES to Novolazarevskaya Air Base on 8 February 2013, and from
Novolazarevskaya to Cape Town on 9 February 2013. The arrival of the Japanese team in
Japan was planned for 14 February 2013.
3.4.Scientific matters
3.4.1.Definition, division, and subdivision of search areas
For convenience, three areas were defined for the meteorite searches on the Nansen Ice
Field: areas A, B, and C (Fig. 1d). Area A was previously searched by JARE-29 and
BELARE 20102011. Areas B and C had only been searched during JARE-29, and were
searched again by the current expedition after a gap of quarter of a century. Twelve daily
search areas (112) were defined in area B, and nine (19) in area C (Fig. 2). The size of
the search areas was chosen on the basis of the areas covered per day in area A during the
BELARE 20102011 expedition.
3.4.2.Logistics and the procedure for meteorite collection
We prepared 0.08-mm-thick ziplock polyethylene sample bags (UNIPACK,
SEISANNIPPONSHA Ltd.) of various sizes to store the collected meteorites: size A (70
50 mm), size C (10070 mm), size E (140100 mm), size F (170120 mm), and size K
(400280 mm). We also used 0.05-mm-thick powder-free polyethylene bags: 4060 cm
size and 20 of 100120 cm size (MZ series, ADY Co., Ltd.). Other equipment included
44 N. Imae et al.
Fig. 1.
Maps (from Google Earth) showing the route from Cape Town to the Nansen
Ice Field and areas searched. (a) Cape Town ( Cape on map) to
Novolazarevskaya Air Base ( Novo). The area within the rectangle is
enlarged in (b). (b) Novolazarevskaya to Princess Elisabeth Station (PES).
SS indicates Syowa Station. The area within the rectangle is enlarged in (c).
(c) Sør Rondane Mountains and the Nansen Ice Field, about 600 km west
of Syowa Station. The routes to and from the Nansen Ice Field are shown
as a blue line. (d) The Nansen Ice Field divided into three search areas (A,
B, and C). The planned (smaller dots) and actual positions (larger dots) of
BC1 and BC2 are also shown.
45Report of the JARE-54 and BELARE 20122013 joint expedition to collect meteorites
marker pens, measuring scales, digital cameras, and hand-held GPS units (Garmin
GPSMAP 62S; mounted on each snowmobile).
On finding a meteorite: (1) the field sample number was written with a marker pen on
the ice near the meteorite and a scale placed beside it; (2) photos of the meteorite (and scale)
were then taken from various viewpoints; (3) the meteorite was picked up using the ziplock
polyethylene bag to avoid direct contact with gloves, then sealed in the ziplock bag and
stored in the field bag; and (4) the position of the meteorite find was recorded by the GPS
unit.
3.4.3.Expected number of meteorite finds
The searches by JARE-29 in 19871989 collected 573 meteorites from area A, 698
from area B, and 311 from area C (Naraoka et al., 1990), and the searches by BELARE
20102011 collected 218 meteorites from area A (Goderis et al., 2011). Assuming the
similar condition of each expedition, the relationship among the three areas in terms of
meteorites found (i.e., 573:698:311218:x:y) could be satisfied, where x and y gave the
number of meteorites that we expected to collect from areas B and C, respectively.
Therefore, the number of meteorites that we expected to recover from area B (x) was about
270, and from area C (y) was about 120, giving a total of 390.
3.4.4.Storage and transport of meteorites
AY and NI asked JET8 Cargo Co. Ltd. (Japan) to transport the collected meteorites
(frozen) from the ALCI warehouse in Cape Town to NIPR in Tokyo.
Fig. 2. Subdivisions of areas B and C for daily meteorite searches.
46 N. Imae et al.
3.5.Logistics
3.5.1.Snowmobiles
We planned to use snowmobiles (Tundra Ski-Doo as used by JARE-49, -50, and -51)
for the meteorite searches. The fuel requirements (supplied from PES) were estimated to be
twenty 200-L drums (total 4000 L) based on the following assumptions: 10 snowmobiles
travelling 50 km per day for 40 days with a fuel consumption of 5 km/L. The two field
assistants used larger snowmobiles (S7 Ski-Doo supplied by BELARE) than the rest of the
team so that they could tow rescue sledges.
3.5.2.Supplies and equipment
The total weight of supplies and equipment sent by air to the ALCI warehouse in Cape
Town in advance of the expedition party (food, clothing, medicine, communication
equipment, and generators; Fig. 3a) was 965 kg (Table 4). The Material Safety Data Sheets
(MSDS) and certificates of non-applicability (of import restrictions) required for personal
notebook computers, used generators, UHF and HF radio equipment, and batteries were
prepared by the Toyo Trans Company, which arranged shipment of these items from the
NIPR warehouse on 3 November, arriving at the ALCI warehouse on 4 November. Two
cartons containing generators and other supplies were transported to the ALCI warehouse
by Singapore Airlines, arriving on 6 November.
3.5.3.Food
Freeze-dried (FD) food, mainly for the JARE-54 teams evening meals (Fig. 3b), was
prepared during early July 2012 by the Nihon Freeze Dry Co. (an Asahi group company) in
Azumino, Nagano Prefecture. Sufficient FD food was prepared for a 55-day expedition,
plus emergency rations for an additional 20 days. There were 20 kinds of FD food sets.
The daily calorie requirement per person was estimated to be at least 3000 kcal. There were
three choices for breakfast: pasta, FD rice, and Chinese noodles. The total weight of the
food was 357 kg, and it was packed into 33 plastic boxes that comprised 20 boxes of main
meals including FD and breakfast, 3 boxes of portable rations (sausage, salami, candy, and
sweet jellied adzuki-bean paste), and 10 boxes of soup, drinks, and emergency foods.
Frozen food for the BELARE team was prepared at PES.
The JARE team used heat from the generator in module B to melt snow to produce
drinking water: a plastic box filled with snow was set beside the generator. The volume of
water consumed each day was 2030 L.
3.5.4.Communications
The JARE team communicated with Syowa Station (SS) daily between 1900 and 1930
LT (Belgium time: GMT1 at PES; GMT3 at SS) using either an HF radio (JSB-20K at
4540.0 KHz) set up in module B, or an Iridium satellite phone set up in module A. The joint
expedition members used Belgium time at PES and on the Nansen Ice Field. The Iridium
satellite phone was used mainly for communication with SS as backup for the HF radio, but
also for communication with team members families in Japan. There were also two
additional Iridium satellite phones for backup. VHF portable radios (Motorola GP340
supplied from PES) were used for communication among the 10 team members during
meteorite searches, and between the JARE and BELARE living quarters. The UHF radios
(icom, IC-UH37CTM) were used mainly for communication between JARE modules.
3.5.5.Clothing
JARE members prepared outer clothing in the field: a down jacket and trousers (Mont-
47Report of the JARE-54 and BELARE 20122013 joint expedition to collect meteorites
Bell Co.), snow boots (Baffin), and a pair of polarized pink double anti-fog lensed goggles
with a silver mirror coating (SWANS, Model HELI-MPDH). Tent shoes (North Face) were
worn in the living quarters. For more details see 54th Japanese Antarctic Research
Expedition (2012).
Fig. 3. (a) Supplies in the Antarctic Ligistics Centre International (ALCI)
warehouse in Cape Town. (b) Packing freeze-dried food into plastic
boxes in the freezer at NIPR.
48 N. Imae et al.
3.5.6.Emergency procedures
The BELARE team was responsible for medical evacuation (MEDEVAC) in the event
of serious injury or illness on the Nansen Ice Field. In the event of an emergency on the
Nansen Ice Field, the trip from PES to the base camps could be completed in 34 hours by
snowmobile. A medical doctor (also a field assistant), Jacques Richon, accompanied the
joint expedition team members on the Nansen Ice Field until 2 January, when he returned to
PES.
In an emergency, a call would be made to PES by Iridium phone, and SS would also be
informed of the situation by Iridium phone or HF radio from the Nansen Ice Field or PES.
If necessary, SS, PES, or NIPR would inform the ALCI office in Cape Town to request a
DROMLAN flight for rescue. SS would inform the head of JARE-54 (Prof. Kentaro
Watanabe) on the icebreaker Shirase, and the head of the Antarctic Operation Center (Prof.
Yoichi Motoyoshi) at NIPR in Tokyo. The communication sequence at the first stage is
summarized in Fig. 4 (Any emergent situation has not occurred at the present expedition.).
4.Expedition log
The duration of the JARE-54 expedition, from departure on 1 December 2012 to return
on 14 February 2013, was 76 days (Table 5). The team spent 65 days in Antarctica (6
December 2012 to 8 February 2013), including 39 days on the Nansen Ice Field (26
December to 2 February; Table 5). The daily schedule on the Nansen Ice Field is shown in
Table 6.
The JARE members checked the supplies transported earlier from NIPR to the ALCI
warehouse at Cape Town Airport at 1000 LT on 4 December 2012. The supplies (excluding
emergency kits, which were carried by team members) were in 68 parcels with a total
weight of 935 kg. We attended a briefing in the ALCI office on 5 December 2012, just
before our departure for Antarctica on a DROMLAN flight.
The members of both teams departed Cape Town Airport at 2315 LT on 5 December
2012 and arrived at Novolazarevskaya Air Base at 0330 LT on 6 December. During a three-
Table 4. Supplies sent in advance by air to ALCI warehouse.
49Report of the JARE-54 and BELARE 20122013 joint expedition to collect meteorites
night stay at Novolazarevskaya, the JARE team met the head of the air base to discuss the
transport of meteorites from Antarctica under frozen conditions. He suggested the
meteorites could be stored in an ice cave at Novolazarevskaya Air Base, if needed, even
though this had not been necessary at Novolazarevskaya Air Base because of the very short
transit as be described in Section 7.2. After a three-night delay due to bad weather at PES,
the JARE team left the air base at 1100 LT on 9 December and arrived at PES at 1330 LT.
The BELARE team left Novolazarevskaya for PES one day earlier than the JARE team.
After the expedition, the JARE (four members) and BELARE (six members) teams left
PES at 1100 LT on 8 February 2013, arrived at Novolazarevskaya at 1200 LT, and then
departed Novolazarevskaya at 1430 LT, arriving at Cape Town Airport at 2030 LT.
5.Preparations at PES
We spent 17 days at PES (Fig. 5a) before our departure for the Nansen Ice Field.
During this period, we prepared for departure and undertook field training as follows.
(1) Snowmobile training: driving, daily maintenance procedures, fuel supply, how to use
hand warmer and grip cover, and repairs (JARE and BELARE).
(2) Crampon training (BELARE only).
(3) Rescue training (JARE and BELARE).
(4) Safe handling of heavy parcels (supplies and equipment; JARE only).
(5) Crevasse rescue (Fig. 5b; JARE and BELARE).
(6) Building emergency shelters (JARE and BELARE).
Fig. 4. Communication diagram for emergency situations.
50 N. Imae et al.
We held several meetings at PES to discuss the following matters related to fieldwork
on the Nansen Ice Field.
(1) Logistics (by Alain Hubert).
(2) How to recognize meteorites and appropriate handling of them (by AY and VD).
Table 5. Daily log for the joint expedition to collect meteorites from the Nansen Ice Field. (1/2)
51Report of the JARE-54 and BELARE 20122013 joint expedition to collect meteorites
(3) Schedule of activities on the Nansen Ice Field (by NI).
(4) Risks of working in cold conditions and at high altitude; avoiding illness and injury (by
Jacques Richon).
Table 5. Daily log for the joint expedition to collect meteorites from the Nansen Ice Field. (2/2)
52 N. Imae et al.
At PES, the JARE members stayed in the living quarters that would later be
transported to the Nansen Ice Field, to become accustomed to them and test their facilities.
The JARE quarters included a kitchen and dining space in module A, and a diesel generator
(100 V) and toilet (Wrappon, Nihon-safety Co., Ltd.) were placed at the entrance of module
B. A 200 V generator housed in one of the BELARE containers was used as a cooking
heater and to charge the VHF portable radios. The JARE team therefore used compatible
portable VHF radios (Motorola) from PES on the Nansen Ice Field. Propane gas was used
in the kitchen of the BELARE quarters.
6.Nansen Ice Field
6.1.Meteorite search in area B
Our search focused on the southwestern Nansen Ice Field until the middle of January,
during which time we stayed at BC1 (7252󰮍19.6󰮎S, 2420󰮍28.0󰮎E; 2909 m elevation). The
Belgian support team (Alain Hubert, Kristof Soete, and Erik Verhagen) left PES on 24
December (two days before the expedition scientists) to set up BC1 in preparation for the
expedition party, who travelled on three Prinoth snow tractors towing sledges carrying the
JARE and BELARE living quarters, as well as fuel and food supplies (Fig. 6a). The
expedition members travelled from PES to the Nansen Ice Field (BC1) on 26 December on
eleven snowmobiles (Fig. 6b) and were accompanied by Jacques Richon, who was also the
navigator on the journey to the ice field. The trip to BC1 took about seven hours, passing
the base camp used during the 20102011 expedition to area A and arriving at BC1 at about
1400 LT. Several problems arose during the trip: the snowmobile driven by the field
assistant with BELARE overheated at the start of the journey, a sledge was overturned
Table 6. Daily schedule on Nansen Ice Field.
53Report of the JARE-54 and BELARE 20122013 joint expedition to collect meteorites
during the trip, goggles became fogged at times, and some of the group suffered mild frost
bite on their faces and fingers. Weather conditions deteriorated when we arrived on the
plateau, where we experienced strong winds, snow drifts, and poor visibility.
The location of BC1 (about 2 km north of the planned location) was determined by
Alain Hubert during his reconnaissance trip. At BC1, the JARE and BELARE living
quarters were about 30 m apart (Fig. 7a and b) and were connected by electric cables.
Snowmobiles were parked about 100 m west of the living quarters, and the Lehman sledge
used to store fuel and food was south of the JARE living quarters (Fig. 7b). Snow drifts
that developed at the camp site are clearly visible in Fig. 7a.
Weather observations (twice daily at 0900 and 1930 LT) using a potable type (Kestrel
4500, NIELSEN-KELLERMAN) by the JARE team during the time spent in area B provided
the following data. Temperatures ranged from 22.4 to 14.4 (average 18.2),
wind speeds were 2.118.0 m/s (average 10.1 m/s), and atmospheric pressure was 671.9
688.7 hPa (average 682.4 hPa; see Table 7 and Fig. 8). Weather conditions were good
Fig. 5. (a) Princess Elisabeth Station (PES). (b) Crevasse rescue training.
54 N. Imae et al.
during our stay in area B (26 December to 15 January). Of the 21 days working from BC1,
15 days were devoted either to meteorite searches or camp moves.
During our meteorite searches, we drove the ten snowmobiles in V-formation, with a
field assistant (YA or CB) at the apex of the V (Figs. 9 and 10a). Our speed in formation
was usually less than 10 km/h. Small mobile GPS units mounted on the snowmobiles (Fig.
10b) were used for navigation, as well as to record the routes followed during the search
and the locations of the meteorites found. These data were used to map the meteorite
distribution on the ice field (Figs. 11 and 12).
Most of the search tracks of the expedition members show closely spaced lines,
reflecting the V-formation used during the search. Single tracks indicate areas where the
Fig. 6. (a) Departure of the IPF support team to the Nansen Ice Field. (b) Departure
of expedition members for a meteorite search on the Nansen Ice Field.
55Report of the JARE-54 and BELARE 20122013 joint expedition to collect meteorites
expedition team travelled in single file because snow conditions were bad or because there
were crevasses in the area. Some GPS data were not recovered, which explains why there
are fewer than ten tracks in some areas where the snowmobiles were travelling in
Fig. 7. Photos and plan views of BC1 and BC2. (a) BC1 viewed from the northwest. (b) and (c) Plan views of
BC1and BC2, respectively. (d) BC2 viewed from the west.
56 N. Imae et al.
V-formation (Figs. 11 and 12).
Typical field occurrences of meteorites found in area B are shown in Fig. 10c. The
highest concentration of meteorites was found in search area 3 of area B (Figs. 2, 11, and
12); the lowest concentration was in search area 12 (Figs. 2, 11, and 12). The weights (and
dates found) of the seven largest meteorites from area B were as follows: 6.6 kg (10
January), 2.6 kg (4 January), 2.2 kg (10 January), 1.6 kg (3 January), 1.3 kg (6 January), 1.2
kg (3 January), and 1.1 kg (6 January), all of which were ordinary chondrites. In total, 368
meteorites were collected in area B (Table 5).
Table 7. Detailed weather
57Report of the JARE-54 and BELARE 20122013 joint expedition to collect meteorites
The schedule for a typical day (Table 6) was as follows. There was a pre-search
briefing at 0930 LT. If weather conditions were good, we left BC at 1200 LT and spent 4 to
6.5 hours searching. On our return to BC, we refueled the snowmobiles for the next day.
Gasoline drums were stored on a Lehman sledge, and the snowmobile gas tanks were filled
using a high-speed pump. The JARE snowmobiles (Tundra Ski-Doo) usually required 10
20 L on a daily basis, but the larger BELARE snowmobiles (S7 Ski-Doo) required 2030 L.
The distance travelled is shown on Table 8.
After AY and TM checked the meteorites collected that day, they were stored in plastic
observations. (1/3)
58 N. Imae et al.
boxes outside the living quarters. We made our daily radio contact with PES (2000 LT) and
SS (1950 LT), and reported the number of meteorites found. At 2030 LT, there was an
evening briefing to plan the next days search. The field guides then prepared the route to be
followed, which was designed to maximize the area covered without exceeding a total travel
distance of 48 km (Table 8), thus avoiding a long day in the harsh environment.
As health and safety matters at BC1, some team members suffered facial frostbite during
the journey from PES to BC1, and there were several falls from snowmobiles in areas of
sastrugi development, which were caused by the poor visibility and lack of visual contrast
Table 7. Detailed weather
59Report of the JARE-54 and BELARE 20122013 joint expedition to collect meteorites
during snow drifts or cloudy weather. There was only one (minor) injury related to these
falls. One member of the BELARE team suffered shoulder pain after a fall and required
one day of rest (13 January).
On the morning of 14 January, the step at the entrance to JARE module A was
completely buried by a snow drift; it took about four hours to uncover the step. The weather
was too bad for fieldwork, so meteorites ready for transport were packed and our move to
area C was considered. The decision was made to give priority to the northern part of area
C, because a previous search (JARE-29) indicated it to be the most promising area. New
observations. (2/3)
60 N. Imae et al.
route coordinates were sent to PES, and the revised search plan was agreed by Alain Hubert.
The rest of the day was spent packing and preparing for the move to area C. At 0400 LT on
15 January, Alain Hubert, Kristof Soete, and David Rigotti arrived at BC1 with two Prinoth
snow tractors, having travelled overnight from PES. At around 0900 LT on 15 January, the
clearing of snow dunes around the camp by the snow tractors began. The members left
BC1 on ten snowmobiles at 1130 LT (about one hour before the snow tractors departure),
for a final two hours of meteorite searching in area B (search area 1, no meteorites found),
before moving on to area C.
Weather conditions deteriorated in the afternoon, with increasing snow drifts and wind.
Table 7. Detailed weather
61Report of the JARE-54 and BELARE 20122013 joint expedition to collect meteorites
The trip from BC1 to BC2 took 5.5 hours (route shown in Fig. 1c). There was a technical
problem with one of the snowmobiles (driven by YA), which we were able to fix (see also
Section 6.4.4), and the ten members arrived at BC2 at 1630 LT. Visibility had deteriorated
to about 5 m by the time we reached BC2, and the wind was strong, so an emergency tent
was set up for shelter while we waited for the support team to arrive with the snow tractors,
about 20 minutes later. The JARE and BELARE living quarters were ready by 1730 and
1830 LT, respectively, and the weather continued to deteriorate.
observations. (3/3)
62 N. Imae et al.
Fig. 8. Temperature, wind speed, and atmospheric pressure observed daily
at 0900 and 1930 LT from 12 December 2012 to 2 February 2013.
The raw data are shown in Table 7.
63Report of the JARE-54 and BELARE 20122013 joint expedition to collect meteorites
6.2.Meteorite search in area C
The remainder of our time on the ice field was meteorite search in area C staying at
BC2 (7242󰮍04.3󰮎S, 2446󰮍40.3󰮎E; 2841 m elevation) in the northeastern Nansen Ice Field
(Fig. 1d). As it had been decided to focus on the northern part of area C, BC2 was set up
about 10 km north of the planned position (Fig. 1d). However, after we had set up at BC2
(Fig. 7c and d), blizzard conditions persisted for 12 consecutive days. During the worst
period, visibility was less than 5 m, severely restricting outdoor activities. Even though the
JARE and BELARE living quarters were separated by only 30 m (Fig. 7c), movement of
team members between them was kept to a minimum during this period. The arrangement
of living quarters at BC2 (Fig. 7c) was the reverse of that at BC1 (Fig. 7b); JARE modules
at BC2 were on the northern side of the site rather than the southern side, as at BC1. The
Lehman sledge used for storage of fuel and food was west of the JARE modules (Fig. 7c),
and was completely buried by a snow drift for the 12 days of the blizzard (Fig. 7d). The
sledge had to be uncovered for access to food, fuel for the generator and snowmobiles, and
stored meteorites. The sledge was eventually pulled out by one of the Prinoth snow tractors
at the end of our stay at BC2. The extent of the snow drifts after the blizzard at BC2 is
shown in Fig. 7c. Snowmobiles were parked about 100 m north of the living quarters (Fig.
7c) and were not seriously affected by snow drifts.

Twice daily weather observations by the JARE team at BC2 provided the following data
(Table 7 and Fig. 8). Temperatures were between 27.1 and 18.2 (average 21.9),
Fig. 9. Schematic plan view of the V formation of snowmobiles (circles) during meteorite
searches. The arrow shows the direction of movement. Initials of expedition
members (see Table 1) are marked beside their position in the formation.
64 N. Imae et al.
wind speeds were 0.015.8 m/s (average 10.6 m/s), and atmospheric pressure was 672.8
687.3 hPa (average 680.6 hPa). During our stay at BC2 (15 January to 2 February), the
weather conditions were very bad. Outside work was possible on only four days: three days
of meteorite searches and one day to return to PES. JARE and BELARE team members
had dinner together more often than the once-a-week average during this period of bad
Fig. 10. Photos taken on the Nansen Ice Field expedition. (a) Photo during the meteorite search. (b) Hand-held
GPS unit (within a circle) for navigation mounted on snowmobiles. (c) Preparing to photograph a
chondritic meteorite found by TM on 1 January. (d) The largest meteorite found during the expedition
(28 January), an ordinary chondrite weighing about 18 kg. (e) Dirty ice band bearing a volcanic ash
deposit in area C.
65Report of the JARE-54 and BELARE 20122013 joint expedition to collect meteorites
weather. The low temperature and blizzard conditions caused technical problems with two
snowmobiles, which required us to use the two backup snowmobiles thereafter. During the
stay at BC2, snow drifts accumulated regularly at the entrance to JARE module B,
obstructing the door and blocking the flow of exhaust gases from the generator. It was often
necessary to shovel snow away from the entrance to the module.
In total, 56 meteorites were collected in area C (Figs. 11 and 12). The largest meteorite
collected during the entire expedition was from area C (about 18 kg; Fig. 10d). The second
largest meteorite from area C weighed 4.1 kg (found on 29 January). However, the
concentration of meteorites in area C was considerably lower than that in area B. The
detailed tracks of the snowmobiles and the locations of the meteorites are shown in Figs. 11
and 12.
After completion of the meteorite search on 30 January, a band of dirty ice was
sampled (Figs. 10e, 11, and 12). Naraoka et al. (1991) sampled ice at many locations on the
Nansen Ice Field and concluded that most of the dirty layers represented volcanic ash
deposits. A few kilograms of dirty ice were collected, which can be used for further study
Fig. 11. Map (Google Earth) showing snowmobile routes (blue line) and locations of meteorites (red points)
found in areas B and C. Sampling locations of ice bearing volcanic ash (black dotted circles) in
area C are also indicated. The close-up views of the rectangular areas are shown in Fig. 12.
66 N. Imae et al.
when required.
We prepared for our return to PES on 31 January and 1 February. The most important
tasks were to pack the meteorites, check the list of samples, and remove snow from the fuel
sledge, which was completely buried by snow. We returned to PES, in very good weather,
on 2 February. The trip took 4.5 hours, and one meteorite was found along the way.
Fig. 12. Close-up view of area B and C in Fig. 11. The recovered 412 points among collected 424 in total
meteorites are plotted. Map (Google Earth) showing snowmobile routes (blue line) and locations
of meteorites (red points) found in areas B and C. Individual snowmobile routes are also indicated.
67Report of the JARE-54 and BELARE 20122013 joint expedition to collect meteorites
6.3.Summary: meteorites found and weather conditions on the Nansen Ice Field
We estimated that we would recover 270 meteorites from area B, but actually collected
368. However, for area C we estimated finding 120 meteorites but collected only 56, and
this was because we were unable to search the southern part of the area. The final number
Table 8. Daily distances (km) driven by snowmobiles.
68 N. Imae et al.
of meteorites collected was 424, which is close to the pre-expedition estimate of about 390
given in Section 3.4.3. The total weight of meteorites recovered was about 70 kg, which
was much greater than the amount recovered by previous expeditions to area A in 2010
2011 (ca. 6 kg) and to the Balchen Ice Field in 20092010 (ca. 13 kg). The tracks and
locations of meteorites obtained by hand-held GPS will be useful for planning future
expeditions and provide basic data that will help to clarify the meteorite concentration
mechanism.
The minimum temperature during the expedition was 31, which was an
unscheduled temperature reading made with a digital temperature meter in the early
morning of 31 January (therefore not shown in Table 7 and Fig. 8). The same temperature
was also recorded (unscheduled) by the Kestrel 4500 instrument at around midnight on
January 30. The temperature decreased considerably after the middle of January, and during
the bad weather of 1526 January, wind speeds were very high and visibility was very poor.
6.4.Problems encountered during the expedition
6.4.1.Snowmobiles
There were several snowmobile breakdowns during the course of the expedition. On 2
January, JARE snowmobile no. 49-4 (used by a BELARE team member) had to be towed
back to BC1 by another snowmobile to repair a broken sprocket. Following the blizzard at
BC2 (28 January onwards), several snowmobiles could not be driven, and it took several
days to repair them. Three snowmobiles broke down over a short period of time during the
meteorite search on 28 January. The V-belts were removed and the drive pulleys were
released from these snowmobiles so they could be towed back to BC2 by the other
snowmobiles.
6.4.2.Heaters in JARE modules
Two sets of diesel-fuelled heaters (a Webasto FF heater of an Air Top Evo 3900 type)
were used in each JARE module. At BC1, one heater in each module broke down, probably
because of their use at an elevation above 2200 m (not guaranteed by the manufacturer). At
BC2, all of the JARE heaters failed. Fortunately, BELARE was able to provide a spare
heater (a 3.3 kW STANLEY stove) for JARE. Without this spare heater, the failure of the
JARE heaters would have been a very serious problem.
6.4.3.Other problems in JARE modules
Significant frost in the bedrooms of both JARE modules was problematic. An increase
in the concentration of carbon monoxide (up to 52 ppm) was detected by the sensor when
the JARE members used the cassette gas stove instead of the electric hot plate.
6.4.4.Danger caused by periods of poor visibility
The weather and visibility deteriorated during the move from BC1 to BC2. During the
trip, a metal component of the caterpillar track of a snowmobile (S7 Ski-Doo, driver YA)
broke, and this snowmobile was towing a rescue sledge in the last position of the convoy.
This damaged snowmobile (S7 Ski-Doo) was left behind, having checked the position with
a hand-held GPS. (The abandoned snowmobile was later picked up by the support team.)
The rescue sledge was then transferred to another snowmobile (Ski-Doo JARE 51-8, driver
NI), and YA rode with HZ on the snowmobile (Ski-Doo JARE 49-4). The snowmobile
(Ski-Doo JARE 51-8), now towing the rescue sledge, was in the second to last position of
the convoy. The last snowmobile (Ski-Doo JARE 49-4 with YA and HZ) in the convoy
69Report of the JARE-54 and BELARE 20122013 joint expedition to collect meteorites
contacted NI by radio, and informed them of the problem that a pin connecting the towing
sledge was disconnected with the snowmobile (JARE 51-8) due to the accidentally released
pin.
During the recovery operation, NI called the field assistant (CB) leading the convoy
and CB stopped the convoy and drove back to assist. During this period, three members
(YA, NI, and HZ) were separated from the main party by about 12 km. Visibility at the
time was less than 10 m. Following snowmobile tracks would have been difficult because
there were no clear snowmobile tracks on the bare ice area. However, CB had entered his
position in his GPS before leaving the main party, so the three members were able to re-join
the main party. This was a very important learning experience regarding the dangers of bad
visibility.
6.4.5.Medical matters
Many of the expedition team members suffered minor frostbite during the expedition,
mainly on the cheeks and fingertips. Several instances of frostbite on the face were
experienced by BELARE members because they wore helmets that were not suitable for
this type of weather; i.e., they were not fully closed and did not protect the face from cold
winds. The affected team members made a full recovery after leaving Antarctica. On a few
occasions, snowmobile rollovers occurred during meteorite searches in areas of sastrugi.
On 27 January at BC2, a team member suffered an asthma attack as clearing snow from a
snowmobile while facing into the strong wind, but recovered after taking medication. The
effects of undertaking strenuous activity in a breathtaking wind should not be
underestimated.
7.Post-expedition activities
7.1.Retrieval of living quarters
After the expedition team returned to PES, Alain Hubert and Kristof Soete of the IPF
support team departed for the ice field to collect the living quarters, returning two days later.
Expedition members then cleaned the living quarters and prepared inventories of their
contents.
7.2.Shipment of meteorites to NIPR
It was essential that the meteorites remained frozen during transport to NIPR. This
was achieved as follows. On the Nansen Ice Field, meteorites were packed into
polyethylene and cloth bags, and stored with refrigerants in three cool boxes (Fig. 13a and
13b), each of which was covered with expanded polystyrene and then placed in a corrugated
cardboard box. The total weight of the three parcels (excluding cool boxes) was 74.1 kg
(#1, 14.4 kg; #2, 16.4 kg; #3, 43.3 kg). Subtracting the weights of polyethylene and cloth
bags, the approximate total mass of the collected meteorites was thus estimated to be about
70 kg. The meteorites were transported from the Nansen Ice Field to PES by Lehman
sledge (Fig. 13c). During the days before departure from PES (2 to 8 February), the cool
boxes were stored in a freezer. They were removed from the freezer immediately before the
1.5 hour flight to Novolazarevskaya Air Base on 8 February. Within 30 minutes of arrival at
Novolazarevskaya, the meteorites were loaded onto a DROMLAN (Ilyushin-76) flight to
70 N. Imae et al.
Cape Town. Only two of the three cool boxes were placed in a freezer in the Ilyushin
warehouse due to the limited capacity. And the one was stored in the usual warehouse. At
Cape Town Airport (on 8 February), they were immediately transferred to a freezer in the
ALCI warehouse.
The JET8 cargo company transported the meteorites from Cape Town to NIPR. Before
departure, they removed the meteorites from the cool boxes used thus far and placed them
in three 5-cm-thick insulated cardboard boxes (internal dimensions 790400340 mm,
107 L) lined with solid carbon dioxide. The meteorites arrived at NIPR on 5 March, after
the supply of additional solid carbon dioxide at Narita airport on 28 February.
At NIPR, we found that the dirty ice samples stored with the collected meteorites had
not melted at all, indicating that the samples were frozen throughout their transport from the
Nansen Ice Field to the freezer in NIPR. After defrosting the collected meteorites under
low-pressure conditions, the classification and curation of the meteorites began in the
laboratory at NIPR.
7.3.Return of other supplies and equipment
Approximately 500 kg of material was sent by surface shipment from the ALCI
warehouse in Cape Town to Tokyo, and this arrived at the NIPR on 9 May.
7.4.Food supplies remaining after the expedition
Twelve plastic boxes of FD food (including five plastic boxes of emergency rations)
Fig. 13. (a) and (b) Packing meteorites into cool boxes for transport from the Nansen Ice Field to the ALCI
warehouse in Cape Town. (c) Cool boxes with outer insulation layer.
71Report of the JARE-54 and BELARE 20122013 joint expedition to collect meteorites
remained after the expedition. FD food was consumed for a total of 47 days and we had
prepared food for 55 days plus 20 days for emergencies. As we had a lot of spare time
during the bad weather, especially the 12 days from 16 to 27 January, the JARE team often
used the ingredients instead of the routine FD food. The only portable food carried during
meteorite searches was candies, because of the difficulty of eating other types of food
without taking off gloves and goggles, which was inadvisable in the cold and often windy
field conditions. Thus, two boxes of portable rations (sausage, salami, candy, and sweet
jellied adzuki-bean paste) were also left over, as were some condiments and powder for
making drinks. All remaining food (except FD food) was left in a container at PES for the
next expedition.
8.Summary
1. We collected 424 meteorites with a total weight of about 70 kg. The heaviest meteorite
was an ordinary chondrite weighing about 18 kg.
2. The number of meteorites collected was close to the forecast based on previous
expeditions.
3.
The meteorites collected during this expedition will be referred to as Asuka 12 meteorites.
4. The snowmobile tracks recorded by hand-held GPS units provide a clear picture of the
areas searched and the distribution of meteorites found on the Nansen Ice Field.
Acknowledgments
We are grateful to the logistics support team at PES, especially the head of PES, Alain
Hubert, his deputy Jacques Richon, and field guide Christophe Berclaz, for their strong
support and guidance. We also thank Mirella Krueger and Vasily Kaliazin of ALCI for their
support with transportation for our expedition. The JARE members are grateful to the
Antarctic Operation Center, especially Yoichi Motoyoshi and Tsuyoshi Nagaki, for their
support. The JARE members also thank the following people; Mikio Abe (Kyokusyoku)
for preparing freeze-dried food, the NIPR geoscience group for providing information on
field conditions in Antarctica, Yusuke Suganuma and Hiroshi Kaiden, who advised on the
basis of their experiences on a recent expedition in the area of the Sør Rondane Mountains,
the main JARE-54 members in the Syowa Station for providing the weather information
and the news through routine radio communication every day, Eisuke Koizumi and Aya
Yamamoto in RESTEC for instruction on the use of the GPS units, and Tomoko Ojima and
Terumi Takami for their support of the preparation. We are also grateful to the Editorial
Board of Antarctic Record for the constructive review. The production of this paper was
supported by the NIPR publication subsidy.
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... The JARE-51, with the participation of a Belgian scientist and the logistic support of PEA, collected 635 meteorites from the Mount Balchen area during the 2009-2010 field season (Kaiden et al., 2010;Tsuchiya et al., 2012). Subsequently, joint JARE and BELARE (Belgian Antarctic Research Expedition) missions were organized on the Nansen BIA by systematic searches on snowmobiles, yielding a total of 974 meteorites in the 2010-2011, 2012-2013 and 2019-2020 seasons (Goderis et al., 2011;Goderis et al., 2021;Imae et al., 2015). Following the successful searches of the Nansen BIA (see Goderis et al., 2021, for an overview), the BELARE 2022-2023 expedition was intended as a reconnaissance field mission to evaluate the meteorite potential of other BIAs in the surrounding of PEA with the main goal to identify new DCAs for future missions. ...
... On blue ice, systematic searches by snowmobiles were performed in a V-shape (Imae et al., 2015), with the field guide at the front and two scientists on each side, separated by ~20 m. The search was divided into two parts, located south and north of the Maquetknausane moraine. ...
... Meteorites were collected and packed into polyethylene bags, avoiding direct contact with hand whenever possible. Provisional naming included the initial of the last name of the finder, then year, month, day, and number of the day, as in the previous expeditions (Goderis et al., 2011;Goderis et al., 2021;Imae et al., 2015). The name was written directly on the ice with a permanent marker, or using a white dive slate and pencil in moraine areas. ...
Article
We provide a comprehensive overview of a reconnaissance expedition aimed at identifying new possible meteorite stranding zones in the surrounding of the Belgian Princess Elisabeth Antarctica (PEA) station in the Sør Rondane Mountains during the BELARE 2022-2023 field season. The team was composed of four scientists and one field guide. Several areas of interest were identified and daily searches occurred in two phases, first from a base camp and then from PEA. The first phase was in the Nils Larsenfjellet area, and a camp, accessible from the H.E. Hansenbreen (S72° 13.260' E22° 37.779'; altitude 1640 m), was set up from December 21 to 27, 2022. Systematic searches were performed in moraines and on blue ice areas (BIAs) during day trips, including the Verheyefjellet BIA, several BIAs surrounding an alignment of nunataks south of PEA, centered on S72° 18.403' E23° 13.191', and the Røysane nunatak at the eastern edge of Nils Larsenfjellet. Four meteorites were recovered during the first phase of the expedition, and another one in the second phase, also in the Nils Larsenfjellet area. In addition, nine surface ice samples and 18 kg of micrometeorite-bearing sediments were collected. Preliminary classification, performed on-site using magnetic susceptibility, tentatively indicated H and L chondrites. The recovered meteorites were transported in frozen state to the Royal Belgian Institute of Natural Sciences in Brussels to be thawed in vacuum conditions and classified based on their mineralogy. The Nils Larsenfjellet is identified as a potential new Dense Collection Area.
... Balchen area . By systematically searching various sections of Nansen Ice Fields, the JARE and Belgian Antarctic Expedition (BELARE) joint expeditions recovered a total of 908 Asuka meteorites in the 2010⊖2011 and 2011⊖2012 seasons (Goderis et al., 2011;Tsuchiya et al., 2012;Imae et al., 2015). The Asuka meteorites include several large specimens such as A 87251 (46 kg) and A 12389 (18 kg), rare meteorites such as angrites (A 881371, A 12209), a lunar meteorite (A 881757), a shergottite (A 12325), unique carbonaceous chondrites (CH3: A 881020, A 881541, A 881691), a Rumuruti chondrite (A 881988), mesosiderites (A 87106, A 881154, and A 882023), 19 diogenites, 11 ureilites, 2 acapulcoites, and 2 ungrouped carbonaceous chondrites. ...
... The first BELAM 2019⊖2020 team meeting was organized in Cape Town, South Africa on 6 January 2020, after the arrival of all the scientific team members on 5 January. During various meetings in the following days, the schedule of the expedition was discussed after studying the targeted blue ice area of Nansen C (Figure 1-d) and considering the details presented by Imae et al. (2015). The main objective of recovering meteorites and sampling blue ice to better constrain the meteorite concentration mechanisms of the Nansen Ice Fields as a whole was discussed in great detail. ...
... The expedition by JARE-29 in 1987⊖1989 collected 573 meteorites from area A, 698 from area B, and 311 from area C (Naraoka et al., 1990;Imae et al., 2012). During the BELARE 2010⊖2011, 218 meteorites were collected from area A (Goderis et al., 2011), while 368 meteorites were recovered from area B and 56 from area C during JARE-54/ BELARE 2012⊖2013 (Debaille et al., 2013;Imae et al., 2015). Assuming similar blue ice conditions and extraction efficiencies for each expedition, an approximate number of meteorites to be recovered was estimated based on the following ratios between the different areas and expeditions (i.e., 573:698:311=218:368:x), where x was the expected number of meteorites to be recovered from area C during the 2019⊖2020 season. ...
Article
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This report summarizes the Belgian Antarctic Expedition (BELARE) 2019-2020 meteorite search and recovery expedition near the Sør Rondane Mountains of East Antarctica during the 2019-2020 field season. This expedition took place from 15 January to 6 February 2020 within the area defined as "C" of the Nansen Ice Fields (S72°38'−72°48'S, 24°35'−25°06'E). The expedition team consisted of four scientists and two field guides, who systematically searched the ice field area and collected 66 meteorites. The total weight of the meteorites was determined to be ~8 kg. In addition to meteorites, blue ice samples, volcanic ash layers, and wind-blown terrestrial rock fragments were collected from the area to study in detail the nature of the mechanisms concentrating meteorites on the Nansen Ice Fields. The recovered meteorites were transported in a frozen state to the National Institute of Polar Research, Japan for dry-thawing and subsequent classification.
... At present, decisions on which areas to visit are largely made according to the availability of logistical support and national government science priorities 7 . In the field, meteorites are often found by human visual identification during grid searches, conducted either on foot or by snow mobile 8 . To increase retrieval rates of such labour-intensive operations, we suggest a major international effort to revisit known sites or access unexplored sites with larger searching teams over the next 10-15 years. ...
... For the lower bound, we did not consider any newly appearing meteorite stranding zones with respect to the reference year 2020. The physical understanding of the meteorite concentration mechanism indicates that there is temporally asymmetric behaviour regarding the (dis) appearance of meteorites (accumulating meteorites takes thousands of years, while they can be lost in a matter of years) 5,8,18 . However, for the upper estimate of the number of meteorites on the continent, we did not discard the limited number of newly appearing meteorites in existing blue ice areas and their near vicinity 9,39 . ...
Article
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More than 60% of meteorite finds on Earth originate from Antarctica. Using a data-driven analysis that identifies meteorite-rich sites in Antarctica, we show climate warming causes many extraterrestrial rocks to be lost from the surface by melting into the ice sheet. At present, approximately 5,000 meteorites become inaccessible per year (versus ~1,000 finds per year) and, independent of the emissions scenario, ~24% will be lost by 2050, potentially rising to ∼76% by 2100 under a high-emissions scenario.
... Black dots represent meteorites. The picture of a meteorite and a folding rule for scale was taken during the JARE-54 (Japanese Antarctic Research Expedition)/BELARE (Belgian Antarctic Research Expedition) 2012-2013 expedition to the Nansen blue ice field(60). ...
Article
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Meteorites provide a unique view into the origin and evolution of the Solar System. Antarctica is the most productive region for recovering meteorites, where these extraterrestrial rocks concentrate at meteorite stranding zones. To date, meteorite-bearing blue ice areas are mostly identified by serendipity and through costly reconnaissance missions. Here, we identify meteorite-rich areas by combining state-of-the-art datasets in a machine learning algorithm and provide continent-wide estimates of the probability to find meteorites at any given location. The resulting set of ca. 600 meteorite stranding zones, with an estimated accuracy of over 80%, reveals the existence of unexplored zones, some of which are located close to research stations. Our analyses suggest that less than 15% of all meteorites at the surface of the Antarctic ice sheet have been recovered to date. The data-driven approach will greatly facilitate the quest to collect the remaining meteorites in a coordinated and cost-effective manner.
... Ice sheet surfaces reach an elevation of about 1000 meter above sea level (masl) north of the SRM and rise to 2500 masl to the South (Suganuma et al., 2014). The region surrounding the Belgian Princess Elisabeth Antarctica (PEA) station was studied using satellite images and geological maps before the start of the 2012-2013 field campaign (Imae et al., 2015). Based on descriptions of the TAM traps (e.g., Rochette et al., 2008;Suavet et al., 2009), erosional and eolian sediment, expected to contain significant extraterrestrial contributions, was subsequently sampled from exposed cracked and fissured surfaces at windexposed, high altitude (>2000 masl) granitoid summits in the western part of the SRM (Figs. 1 and 2). ...
Article
A newly discovered sedimentary accumulation of micrometeorites in the Sor Rondane Mountains of East Antarctica, close to the Wideroefjellet summit at similar to 2750 m above sea level, is characterized in this work. The focus here lies on 2099 melted cosmic spherules larger than 200 mu m, extracted from 3.2 kg of sampled sediment. Although the Wideroefjellet deposit shares similarities to the micrometeorite traps encountered in the Transantarctic Mountains, both subtle and more distinct differences in the physicochemical properties of the retrieved extraterrestrial particles and sedimentary host deposits are discernable (e.g., types of bedrock, degree of wind exposure, abundance of metal-rich particles). Unlike the Frontier Mountain and Miller Butte sedimentary traps, the size fraction below 240 mu m indicates some degree of sorting at Wideroefjellet, potentially through the redistribution by wind, preferential alteration of smaller particles, or processing biases. However, the cosmic spherules larger than 300 mu m appear largely unbiased following their size distribution, frequency by textural type, and bulk chemical compositions. Based on the available bedrock exposure ages for the Sor Rondane Mountains, extraterrestrial dust is estimated to have accumulated over a time span of similar to 1-3 Ma at Wideroefjellet. Consequently, the Wideroefjellet collection reflects a substantial reservoir to sample the micrometeorite influx over this time interval. Petrographic observations and 3D microscopic CT imaging are combined with chemical and triple-oxygen isotopic analyses of silicate-rich cosmic spherules larger than 325 mu m. The major element composition of 49 cosmic spherules confirms their principally chondritic parentage. For 18 glassy, 15 barred olivine, and 11 cryptocrystalline cosmic spherules, trace element concentrations are also reported on. Based on comparison with evaporation experiments reported in literature and accounting for siderophile and chalcophile element losses during high-density phase segregation and ejection, the observed compositional sequence largely reflects progressive heating and evaporation during atmospheric passage accompanied by significant redox shifts, although the influence of (refractory) chondrite mineral constituents and terrestrial alteration cannot be excluded in all cases. Twenty-eight cosmic spherules larger than 325 mu m analyzed for triple-oxygen isotope ratios confirm inheritance from mostly carbonaceous chondritic precursor materials (similar to 55% of the particles). Yet, similar to 30% of the measured cosmic spherules and similar to 50% of all glassy cosmic spherules are characterized by oxygen isotope ratios above the terrestrial fractionation line, implying genetic links to ordinary chondrites and parent bodies currently unsampled by meteorites. The structural, textural, chemical, and isotopic characteristics of the cosmic spherules from the Sor Rondane Mountains, and particularly the high proportion of Mg-rich glass particles contained therein, imply a well-preserved and representative new sedimentary micrometeorite collection from a previously unstudied region in East Antarctica characterized by distinct geological and exposure histories.
Article
Upon passage through Earth's atmosphere, micrometeorites undergo variable degrees of melting and evaporation. Among the various textural and chemical groups recognized among cosmic spherules, that is, melted micrometeorites, a subset of particles may indicate anomalously high degrees of vaporization based on their chemical and isotopic properties. Here, a selection of such refractory element‐enriched cosmic spherules from Widerøefjellet (Sør Rondane Mountains, East Antarctica) is characterized for their petrographic features, major and trace element concentrations ( N = 35), and oxygen isotopic compositions ( N = 23). Following chemical classification, the highly vaporized particles can be assigned to either the “CAT‐like” or the “High Ca‐Al” cosmic spherule groups. However, through the combination of major and trace element concentrations and oxygen isotopic data, a larger diversity of processes and precursor materials are identified that lead to the final compositions of refractory element‐enriched particles. These include fragmentation, disproportional sampling of specific mineral constituents, differential melting, metal bead extraction, redox shifts, and evaporation. Based on specific element concentrations (e.g., Sc, Zr, Eu, Tm) and ratios (e.g., Fe/Mg, CaO + Al 2 O 3 /Sc + Y + Zr + Hf), and variations of O isotope compositions, “CAT‐like” and “High Ca‐Al” cosmic spherules likely represent a continuum between mineral endmembers from both primitive and differentiated parent bodies that experienced variable degrees of evaporation.
Article
Asuka (A) 12325 is the first poikilitic shergottite having a depleted pattern in light rare earth elements (REE). Compared with known poikilitic shergottites, A 12325 has smaller but more abundant pyroxene oikocrysts with remarkable Fe‐rich pigeonite rims, indicating that A 12325 cooled relatively faster at a shallower part of the crust. The redox condition (log f O 2 = IW + 0.6‐IW + 1.7) and Fe‐rich chemical compositions of each mineral in A 12325 are close to enriched shergottites. The intermediate shergottites could not form by a simple mixing between parent magmas of A 12325 and enriched shergottites. Although A 12325 contains various high‐pressure minerals such as majorite and ringwoodite, plagioclase is only partly maskelynitized. Therefore, the maximum shock pressure may be within 17–22 GPa. Thermal conduction and ringwoodite growth calculation around a shock vein revealed that the shock dwell time of A 12325 is at least 40 ms. The weaker shock pressure and longer shock dwell time in A 12325 may be attained by an impact event similar to those of nakhlites and Northwest Africa (NWA) 8159. Such a weak shock ejection event may be as common on Mars as a severe shock event recorded in shergottites. Alteration of sulfide observed in A 12325 may imply the presence of magmatic fluid in its reservoir on Mars. A 12325 expands a chemical variety of Martian rocks and has a unique shock history among poikilitic shergottites while A 12325 also implies that poikilitic shergottites are common rocks on Mars regardless of their sources.
Article
Mineralogy of fine-grained matrix (FGM), fine-grained rim (FGR), chondrule rim, and altered mesostasis of a chondrule from the Asuka (A) 12169 CM3.0 chondrite was investigated by field emission scanning electron microscopy (FE-SEM), synchrotron radiation-based X-ray nano-tomography (SR-XCT), and transmission electron microscopy (TEM). SR-XCT and TEM observations revealed that both FGM and FGR contain abundant amorphous silicate embedding nano-inclusions (most are Fe–Ni sulfide). Although the amorphous silicate is more or less hydrated based on the analysis of the X-ray linear attenuation coefficients in SR-XCT, there are no areas filled by abundant phyllosilicate even in three dimensions. However, FGM and FGR contain ~2-10 μm-sized aggregates composed of tochilinite, nano-inclusions of possible magnetite, and poorly crystalline serpentine without sharp boundaries with the surroundings. It is unlikely that the heterogeneity resulted from brecciation and mixing of materials that experienced different degrees of aqueous alteration, but more likely from a very early stage of aqueous alteration that proceeded heterogeneously depending on locally different chemistry. Chondrule mesostasis near the surface of a chondrule was altered to saponite with tochilinite-rich aggregates. These observations indicate that the degree aqueous alteration of A 12169 is very low and that it is comparable with that of Acfer 094, ALH 77307, and the least altered areas of Paris.
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Following their fall to Earth, meteorites experience weathering. In this systematic study, we evaluate the trace element composition of ordinary chondrites from the Antarctic cold desert, and Atacama (Chile) and Lut (Iran) hot deserts, with an emphasis on rare earth elements (REE). Our data confirms that terrestrial weathering of meteorites in hot deserts changes their trace element (Sr, Ba, REE, Hf, Th, and U) concentrations. However, weathering effects in majority of Antarctic samples are limited to slight Ba, REE, Hf, and Th depletions and in some case to U enrichment. In comparison to the Antarctic meteorites, hot desert samples show greater disturbances and REE fractionation relative to the average fall values. We measured the Sm-Nd isotopic composition of the hot desert meteorites that have heavily affected REE compositions. Our Sm-Nd isotopic data show a significant effect of terrestrial weathering evidenced by non-CHUR 147Sm/144Nd and 143Nd/144Nd ratios. Measurements show a higher variation and lower values of 147Sm/144Nd for the Atacama samples than those from the Lut Desert. Deviations from CHUR 147Sm/144Nd value are in positive accordance with the degree of La/Lu fractionation caused by weathering. The ɛNd values of Atacama and Lut deserts meteorites range from -2.20 to +1.61, which is wider than the -1.07 to +0.64 range for falls. We suggest that disturbance of primary Sm/Nd ratios resulting from mixing with terrestrial components originating from soil during weathering is responsible for lower 147Sm/144Nd ratio in these meteorites. The majority of the Atacama meteorites regardless of their weathering degrees have their REE compositions and ɛNd affected by terrestrial contamination. Both 147Sm/144Nd ratio and ɛNd values show no straightforward relationship with weathering degree. However, in both cases the samples with the highest negative isotopic disturbances are H chondrites from the Atacama and Lut deserts. In addition, Ba concentration shows a negative correlation with 147Sm/144Nd ratio. Care must be taken into account while dealing with samples collected from hot deserts, even fresh-looking ones.
Article
CM chondrites (CMs) are the most abundant group of carbonaceous chondrites. CMs experienced varying degrees of secondary aqueous alteration and heating that modified or destroyed their primitive features. We have studied three chondrites, Asuka (A) 12085, A 12169, and A 12236. Their modal compositions, chondrule size distributions, and bulk composition indicate that they are CMs. However, the common occurrence of melilite in CAIs and glass in chondrules, abundant Fe–Ni metal, the absence of tochilinite-cronstedtite intergrowths, and almost no phyllosilicates, all suggest that these chondrites, especially A 12169, experienced only minimal aqueous alteration. The textures and compositions of metal and sulfides, the lack of ferroan rims on AOA olivines, the compositional distribution of ferroan olivine, and the Raman spectra of their matrices, indicate that these chondrites experienced neither significant heating nor dehydration. These chondrites, especially A 12169, are the most primitive CMs so far reported. The degree of the alteration increases from A 12169, through A 12236, to A 12085. We propose the criteria for subtypes of 3.0–2.8 for CMs. A 12169, A 12236, and A 12085 are classified as subtype 3.0, 2.9, and 2.8, respectively. The oxygen isotopic composition of the Asuka CMs is consistent with these samples having experienced only a limited degree of aqueous alteration. The CM and CO groups are probably not derived from a single heterogeneous parent body. These chondrites are also of particular significance in view of the imminent return of sample material from the asteroids Ryugu and Bennu.
Article
Earth science-related field activities, involving geology, geomorphology and meteorite searches, were carried out in the Sor Rondane Mountains, Eastern Dronning Maud Land, during the 2009-2010 summer season as a part of the 51st Japanese Antarctic Research Expedition (JARE-51), in collaboration with the Belgian Antarctic Research Expedition (BELARE). Geology and geomorphology parties accessed the Sør Rondane Mountains using the Dronning Maud Land Air Network (DROMLAN), and the meteorite search party to Antarctica on the maiden voyage by the new Japanese icebreaker Shirase. The geology party covered the entire area of the Sør Rondane Mountains, although with an emphasis on the eastern part. The geomorphology party carried out fieldwork in western and central parts of the mountains, and the meteorite search party performed a survey in the eastern part. All field activities were successfully carried out. Some of the geology members returned to Japan by DROMLAN, while others flew to Syowa Station from the Sør Rondane Mountains by DROMLAN, and then returned to Japan on board Shirase. This report provides a summary of the field operations, including logistics and weather records.
Article
1969年12月,第10次日本南極地域観測隊の内陸調査旅行のさい,筆者らはやまと山脈南東,南緯71°50',東経36°15'付近の裸氷斜面上で隕石を9箇発見,採集した.これは,隕石採集を主目的として,計画的になされたものではないので,隕石の分布ひんどはかなり高そうである.この付近の地域や,類似の氷床の構造のところでは,今後も発見できそうである.採集された隕石はエコンドライト1箇,コンドライト8箇で,岩質からみて,少なくとも6種類(コンドライト5種,エコンドライト1種)の隕石である.
Implementation planning sheet on the geological field survey in the Sør Rondane Mountains area by 51st Japanese Antarctic Research Expedition
References 51st Japanese Antarctic Research Expedition (2009): Implementation planning sheet on the geological field survey in the Sør Rondane Mountains area by 51st Japanese Antarctic Research Expedition. Tokyo, National Institute of Polar Research, 340 p. (in Japanese).
Implementation planning sheet on the meteorite search in the Sør Rondane Mountains area by 54th Japanese Antarctic Research Expedition
54th Japanese Antarctic Research Expedition (2012): Implementation planning sheet on the meteorite search in the Sør Rondane Mountains area by 54th Japanese Antarctic Research Expedition. Tokyo, National Institute of Polar Research, 187 p. (in Japanese).
  • V Debaille
  • N Imae
  • A Yamaguchi
  • S Goderis
  • T Mikouchi
  • W Debouge
  • G Hublet
  • N Van Roosbroek
  • H Zekollari
  • H Kojima
  • Claeys
Debaille, V., Imae, N., Yamaguchi, A., Goderis, S., Mikouchi, T., Debouge, W., Hublet, G., Van Roosbroek, N., Zekollari, H., Kojima, H. and Claeys. Ph. (2013): The 2012⊖2013 joint field campaign for collecting meteorites in Antarctica: an efficient collaboration between Japan and Belgium. Antarctic Meteorites XXXVI. Tokyo, 2013-11-14/15. National Institute of Polar Research, 11⊖12.
Belgian-Japanese search for Antarctic meteorites during the 2010⊖2011 field season
  • S Goderis
  • H Kaiden
  • V Debaille
  • H Kojima
  • Ph Claeys
Goderis, S., Kaiden, H., Debaille, V., Kojima, H. and Claeys, Ph. (2011): Belgian-Japanese search for Antarctic meteorites during the 2010⊖2011 field season. Antarctic Meteorites XXXIV. Tokyo, 2011-11-17/18. National Institute of Polar Research, 12.
The plan of the search for Antarctic meteorites on the Nansen Ice Field by the joint expedition between JARE-54 and BELARE 2012⊖2013
  • N Imae
  • Y Akada
  • Ph Claeys
  • V Debaille
  • S Goderis
  • G Hublet
  • H Kojima
  • C Martin
  • T Mikouchi
  • N Van Roosbroek
  • A Yamaguchi
  • H Zekollari
Imae, N., Akada, Y., Claeys, Ph., Debaille, V., Goderis, S., Hublet, G., Kojima, H., Martin, C., Mikouchi, T., Van Roosbroek, N., Yamaguchi, A. and Zekollari, H. (2012): The plan of the search for Antarctic meteorites on the Nansen Ice Field by the joint expedition between JARE-54 and BELARE 2012⊖2013. Antarctic Meteorites XXXV. Tokyo, 2012-11-29/30. National Institute of Polar Research, 22⊖23.