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                                                                EXHIBIT 10.12(j)


                             SUPPLEMENTAL AGREEMENT



         This Supplemental Agreement dated April 2, 2000, by and between UNION
PACIFIC RESOURCES GROUP, INC., a Utah corporation (the "Company"), and George
Lindahl III (the "Executive") (the "Supplemental Agreement") is intended to (1)
provide the Executive, subject to the occurrence of contingency stated below,
with certain enhanced rights and benefits supplemental to those the Executive is
currently entitled to receive pursuant to the Executive's Agreement with the
Company dated on or about _________ __, 19__ dealing with a Change in Control of
the Company (the "Agreement") and (2) clarify the relationship between a certain
provision of the Agreement and a similar provision in the Company's Supplemental
Pension Plan.

         WHEREAS, the Board of Directors of the Company, at a meeting held on
March 30, 2000, approved of the Company's entering into formal merger
negotiations with Anadarko Petroleum Corporation ("Expansion");

         WHEREAS, the merger, if consummated, would result in the Company's
becoming a wholly-owned subsidiary of Expansion and would cause a Change of
Control of the Company, as such term is defined in the Agreement (the "Subject
Merger");

         WHEREAS, the Board believes it to be in the best interests of the
Company that if the Company enters into the Subject Merger, the Executive should
be afforded certain enhanced change-of-control benefits which, when added to his
current benefits under the Agreement, would bring the total of such benefits
into relative parity with those change-of-control benefits afforded similarly
situated executives of Expansion;

         NOW THEREFORE, in consideration of the premises and the mutual
covenants herein contained, the Company and the Executive hereby agree as
follows:


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         1. DEFINED TERMS. Each capitalized term used herein has the same
meaning assigned to such term in the Agreement, except as may be otherwise
provided herein.

         2. SUPPLEMENTAL BENEFITS. All rights and benefits afforded to and all
duties and obligations imposed upon Executive under the Agreement shall remain
in full force and effect except as otherwise enhanced or supplemented below:

                  2.1 With respect to Section 6.1(A) of the Agreement, the lump
sum severance payment described therein shall equal (a) a multiplier of at least
3 times base salary; plus (b) 3 times a bonus factor based on the greater of (i)
the highest annual bonus earned by the Executive during the three-year period
preceding the Change of Control or (ii) the annual bonus paid or payable to the
Executive for the year immediately preceding the Executive's year of
termination, in each case, including any bonus or portion thereof which has been
earned but deferred (and annualized for any fiscal year consisting of less than
twelve full months or during which the Executive was employed for less than
twelve full months); plus (c) a pro rata bonus based on the number of months in
the short fiscal year ending immediately prior to the Change of Control
determined on the basis of the greater of the amount described in Section
2.1(b)(i) or Section 2.1(b)(ii).

                  2.2 With respect to Section 6.1(C) of the Agreement, for
purposes of calculating the Executive's benefit under the Company's Supplemental
Pension Plan, the Executive's age at Date of Termination shall be advanced by
three years.

                  2.3 With respect to the last sentence of Section 6.1 of the
Agreement, if the Executive terminates employment with the Company by means of a
Discretionary Termination, he shall, instead of being entitled to 50% of the
Severance Benefits set forth in Section 6.1(A)-(F) of the Agreement, be entitled
to 100% of such Severance Benefits.


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                  2.4 The Company shall, at its sole expense as incurred,
provide the Executive with (a) financial planning services until the third
anniversary of the Date of Termination as provided immediately prior to the Date
of Termination at a cost not to exceed $7,500 annually, and (b) outplacement
services at a cost to the Company not to exceed $100,000, the scope and provider
of which shall be selected by the Executive in the Executive's sole discretion.

         3. EFFECT ON OTHER BENEFITS. The Executive, by executing this
Supplemental Agreement, acknowledges and agrees that, in consideration for the
opportunity to receive the benefit enhancements and supplements provided herein,
the Agreement and, if applicable, the Supplemental Agreement, provide the sole
change-of-control benefits owing to the Executive upon a Change of Control and
that the change-of-control benefit described in Section 3.6 of the Company's
Supplemental Pension Plan and any other change-of-control benefit which may be
described in any other plan adopted and maintained by the Company prior to the
execution of the

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Agreement does not apply to the Executive as long as he is covered by the
Agreement and, if applicable, the Supplemental Agreement.

         4. DEEMED AMENDMENT OF SUPPLEMENTAL AGREEMENT. In the event that on or
after the date of execution of this Supplemental Agreement, Expansion amends or
modifies any of its agreements or arrangements applicable to any employee of
Expansion who is in a position comparable to Executive or directly or indirectly
provides an enhanced benefit to such an Expansion employee,or it is discovered
that Expansion took such action prior to the date of execution of this
Supplemental Agreement which action was not fully disclosed to the Company until
after the date of execution of this Agreement, in any case in connection with
the Subject Merger, this Supplemental Agreement shall be deemed to be amended to
include, mutatis mutandis, an additional benefit to the Executive in a form and
of value equivalent to the enhanced benefit provided to such Expansion employee;
provided, however, that the additional benefit contemplated by this Section 4
shall be payable to the Executive only under such circumstances as the enhanced
benefit would be payable to such Expansion employee.

         5. EFFECTIVE DATE. The Supplemental Benefits set forth in Sections 2
and 4 hereof shall become effective if, and only if, the Executive meets his/her
obligations under Section 4 of the Summary of the Union Pacific Resources Group,
Inc. Change in Control Agreement applicable to the Executive.

                                 UNION PACIFIC RESOURCES GROUP, INC.

                                 By:
                                    --------------------------------------------

                                 EXECUTIVE

                                 By:
                                    --------------------------------------------
                                              George Lindahl III



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